Segui questo link per vedere altri tipi di pubblicazioni sul tema: Evolution (Biology) Adaptation (Biology) Insects.
Articoli di riviste sul tema "Evolution (Biology) Adaptation (Biology) Insects"
Cita una fonte nei formati APA, MLA, Chicago, Harvard e in molti altri stili
Vedi i top-50 articoli di riviste per l'attività di ricerca sul tema "Evolution (Biology) Adaptation (Biology) Insects".
Accanto a ogni fonte nell'elenco di riferimenti c'è un pulsante "Aggiungi alla bibliografia". Premilo e genereremo automaticamente la citazione bibliografica dell'opera scelta nello stile citazionale di cui hai bisogno: APA, MLA, Harvard, Chicago, Vancouver ecc.
Puoi anche scaricare il testo completo della pubblicazione scientifica nel formato .pdf e leggere online l'abstract (il sommario) dell'opera se è presente nei metadati.
Vedi gli articoli di riviste di molte aree scientifiche e compila una bibliografia corretta.
1
SMALL, ERNEST. "INSECT PESTS AND THE EVOLUTION OF DEFENSIVE GLANDULAR TRICHOMES IN ALFALFA". Canadian Journal of Plant Science 65, n. 3 (1 luglio 1985): 589–96. http://dx.doi.org/10.4141/cjps85-081.
Testo completoAbstract (sommario):
Glandular trichomes can defend (Medicago species from herbivores in a variety of insect orders. Wild alfalfas with high concentrations of glandular trichomes occur in a restricted portion of the geographical range of the species (Medicago saliva L. sensu lato), especially in the Caucasus, Ukraine, and adjacent areas of the USSR. These observations suggest that this adaptation was developed to defend the alfalfa against insect pests with similar geographical distribution. That M. sativa plants with pods covered with glandular hairs tend to have larger, if fewer, seeds than plants with pods lacking the hairs also suggests an adaptation against herbivores. Because the glandular trichomes occur primarily on the ovaries and pods, the pests likely feed on seeds. After considering the biology and geography of the major Soviet insect pests of cultivated alfalfa, it was concluded that the most likely insects responsible for the localized evolution of pod glandularity are species of Tychius (Coleoptera: Curculionidae).Key words: Alfalfa, Medicago sativa L., seed chalcid, Brachophagus, Tychius, glandular trichomes, pest resistance (immunity)
2
Yang, Lu, Nitin Ravikanthachari, Ricardo Mariño-Pérez, Riddhi Deshmukh, Mariana Wu, Adam Rosenstein, Krushnamegh Kunte, Hojun Song e Peter Andolfatto. "Predictability in the evolution of Orthopteran cardenolide insensitivity". Philosophical Transactions of the Royal Society B: Biological Sciences 374, n. 1777 (3 giugno 2019): 20180246. http://dx.doi.org/10.1098/rstb.2018.0246.
Testo completoAbstract (sommario):
The repeated evolutionary specialization of distantly related insects to cardenolide-containing host plants provides a stunning example of parallel adaptation. Hundreds of herbivorous insect species have independently evolved insensitivity to cardenolides, which are potent inhibitors of the alpha-subunit of Na + ,K + -ATPase (ATPα). Previous studies investigating ATPα-mediated cardenolide insensitivity in five insect orders have revealed remarkably high levels of parallelism in the evolution of this trait, including the frequent occurrence of parallel amino acid substitutions at two sites and recurrent episodes of duplication followed by neo-functionalization. Here we add data for a sixth insect order, Orthoptera, which includes an ancient group of highly aposematic cardenolide-sequestering grasshoppers in the family Pyrgomorphidae. We find that Orthopterans exhibit largely predictable patterns of evolution of insensitivity established by sampling other insect orders. Taken together the data lend further support to the proposal that negative pleiotropic constraints are a key determinant in the evolution of cardenolide insensitivity in insects. Furthermore, analysis of our expanded taxonomic survey implicates positive selection acting on site 111 of cardenolide-sequestering species with a single-copy of ATPα, and sites 115, 118 and 122 in lineages with neo-functionalized duplicate copies, all of which are sites of frequent parallel amino acid substitution. This article is part of the theme issue ‘Convergent evolution in the genomics era: new insights and directions’.
3
Dai, Xiangping, Takashi Kiuchi, Yanyan Zhou, Shunze Jia, Yusong Xu, Susumu Katsuma, Toru Shimada e Huabing Wang. "Horizontal Gene Transfer and Gene Duplication of β-Fructofuranosidase Confer Lepidopteran Insects Metabolic Benefits". Molecular Biology and Evolution 38, n. 7 (19 marzo 2021): 2897–914. http://dx.doi.org/10.1093/molbev/msab080.
Testo completoAbstract (sommario):
Abstract Horizontal gene transfer (HGT) is a potentially critical source of material for ecological adaptation and the evolution of novel genetic traits. However, reports on posttransfer duplication in organism genomes are lacking, and the evolutionary advantages conferred on the recipient are generally poorly understood. Sucrase plays an important role in insect physiological growth and development. Here, we performed a comprehensive analysis of the evolution of insect β-fructofuranosidase transferred from bacteria via HGT. We found that posttransfer duplications of β-fructofuranosidase were widespread in Lepidoptera and sporadic occurrences of β-fructofuranosidase were found in Coleoptera and Hymenoptera. β-fructofuranosidase genes often undergo modifications, such as gene duplication, differential gene loss, and changes in mutation rates. Lepidopteran β-fructofuranosidase gene (SUC) clusters showed marked divergence in gene expression patterns and enzymatic properties in Bombyx mori (moth) and Papilio xuthus (butterfly). We generated SUC1 mutations in B. mori using CRISPR/Cas9 to thoroughly examine the physiological function of SUC. BmSUC1 mutant larvae were viable but displayed delayed growth and reduced sucrase activities that included susceptibility to the sugar mimic alkaloid found in high concentrations in mulberry. BmSUC1 served as a critical sucrase and supported metabolic homeostasis in the larval midgut and silk gland, suggesting that gene transfer of β-fructofuranosidase enhanced the digestive and metabolic adaptation of lepidopteran insects. These findings highlight not only the universal function of β-fructofuranosidase with a link to the maintenance of carbohydrate metabolism but also an underexplored function in the silk gland. This study expands our knowledge of posttransfer duplication and subsequent functional diversification in the adaptive evolution and lineage-specific adaptation of organisms.
4
Fernández, Rosa, Marina Marcet-Houben, Fabrice Legeai, Gautier Richard, Stéphanie Robin, Valentin Wucher, Cinta Pegueroles, Toni Gabaldón e Denis Tagu. "Selection following Gene Duplication Shapes Recent Genome Evolution in the Pea Aphid Acyrthosiphon pisum". Molecular Biology and Evolution 37, n. 9 (2 maggio 2020): 2601–15. http://dx.doi.org/10.1093/molbev/msaa110.
Testo completoAbstract (sommario):
Abstract Ecology of insects is as wide as their diversity, which reflects their high capacity of adaptation in most of the environments of our planet. Aphids, with over 4,000 species, have developed a series of adaptations including a high phenotypic plasticity and the ability to feed on the phloem sap of plants, which is enriched in sugars derived from photosynthesis. Recent analyses of aphid genomes have indicated a high level of shared ancestral gene duplications that might represent a basis for genetic innovation and broad adaptations. In addition, there are a large number of recent, species-specific gene duplications whose role in adaptation remains poorly understood. Here, we tested whether duplicates specific to the pea aphid Acyrthosiphon pisum are related to genomic innovation by combining comparative genomics, transcriptomics, and chromatin accessibility analyses. Consistent with large levels of neofunctionalization, we found that most of the recent pairs of gene duplicates evolved asymmetrically, showing divergent patterns of positive selection and gene expression. Genes under selection involved a plethora of biological functions, suggesting that neofunctionalization and tissue specificity, among other evolutionary mechanisms, have orchestrated the evolution of recent paralogs in the pea aphid and may have facilitated host–symbiont cooperation. Our comprehensive phylogenomics analysis allowed us to tackle the history of duplicated genes to pave the road toward understanding the role of gene duplication in ecological adaptation.
5
Manni, Mosè, Felipe A. Simao, Hugh M. Robertson, Marco A. Gabaglio, Robert M. Waterhouse, Bernhard Misof, Oliver Niehuis, Nikolaus U. Szucsich e Evgeny M. Zdobnov. "The Genome of the Blind Soil-Dwelling and Ancestrally Wingless Dipluran Campodea augens: A Key Reference Hexapod for Studying the Emergence of Insect Innovations". Genome Biology and Evolution 12, n. 1 (3 dicembre 2019): 3534–49. http://dx.doi.org/10.1093/gbe/evz260.
Testo completoAbstract (sommario):
Abstract The dipluran two-pronged bristletail Campodea augens is a blind ancestrally wingless hexapod with the remarkable capacity to regenerate lost body appendages such as its long antennae. As sister group to Insecta (sensu stricto), Diplura are key to understanding the early evolution of hexapods and the origin and evolution of insects. Here we report the 1.2-Gb draft genome of C. augens and results from comparative genomic analyses with other arthropods. In C. augens, we uncovered the largest chemosensory gene repertoire of ionotropic receptors in the animal kingdom, a massive expansion that might compensate for the loss of vision. We found a paucity of photoreceptor genes mirroring at the genomic level the secondary loss of an ancestral external photoreceptor organ. Expansions of detoxification and carbohydrate metabolism gene families might reflect adaptations for foraging behavior, and duplicated apoptotic genes might underlie its high regenerative potential. The C. augens genome represents one of the key references for studying the emergence of genomic innovations in insects, the most diverse animal group, and opens up novel opportunities to study the under-explored biology of diplurans.
6
Denlinger, David L., Daniel A. Hahn, Christine Merlin, Christina M. Holzapfel e William E. Bradshaw. "Keeping time without a spine: what can the insect clock teach us about seasonal adaptation?" Philosophical Transactions of the Royal Society B: Biological Sciences 372, n. 1734 (9 ottobre 2017): 20160257. http://dx.doi.org/10.1098/rstb.2016.0257.
Testo completoAbstract (sommario):
Seasonal change in daylength (photoperiod) is widely used by insects to regulate temporal patterns of development and behaviour, including the timing of diapause (dormancy) and migration. Flexibility of the photoperiodic response is critical for rapid shifts to new hosts, survival in the face of global climate change and to reproductive isolation. At the same time, the daily circadian clock is also essential for development, diapause and multiple behaviours, including correct flight orientation during long-distance migration. Although studied for decades, how these two critical biological timing mechanisms are integrated is poorly understood, in part because the core circadian clock genes are all transcription factors or regulators that are able to exert multiple effects throughout the genome. In this chapter, we discuss clocks in the wild from the perspective of diverse insect groups across eco-geographic contexts from the Antarctic to the tropical regions of Earth. Application of the expanding tool box of molecular techniques will lead us to distinguish universal from unique mechanisms underlying the evolution of circadian and photoperiodic timing, and their interaction across taxonomic and ecological contexts represented by insects. This article is part of the themed issue ‘Wild clocks: integrating chronobiology and ecology to understand timekeeping in free-living animals’.
7
Glendinning, John I., Stephanie Domdom e Eliza Long. "Selective adaptation to noxious foods by a herbivorous insect". Journal of Experimental Biology 204, n. 19 (1 ottobre 2001): 3355–67. http://dx.doi.org/10.1242/jeb.204.19.3355.
Testo completoAbstract (sommario):
SUMMARYWhen animals repeatedly sample a noxious food over a period of 1–4 days, they can markedly reduce their aversive behavioral response to the diet’s unpleasant taste (e.g. ‘bitterness’) or toxic effects. This long-term adaptation process is selective, however, permitting insects to adapt physiologically to some but not all noxious foods. We hypothesized (i) that the selective nature of this adaptation process stems from the fact that some unpalatable foods are toxic while others are harmless and (ii) that insects have more difficulty adapting to foods that are both unpalatable and toxic. Our model system consisted of Manduca sexta caterpillars and two compounds that taste bitter to humans and elicit an aversive behavioral response in this insect (salicin and aristolochic acid). We found that 2 days of exposure to a salicin diet completely adapted the aversive response of the caterpillars to salicin, but that exposure to an aristolochic acid diet failed to adapt the aversive response to aristolochic acid. We determined that M. sexta could not adapt to the aristolochic acid diet because it lacked mechanisms for reducing the compound’s toxicity. In contrast, the salicin diet did not produce any apparent toxic effects, and the caterpillars adapted to its aversive taste within 12 h of exposure. We also found that the salicin adaptation phenomenon (i) was mediated by the central gustatory system, (ii) generalized to salicin concentrations that were twice those in the adapting diet and (iii) offset spontaneously when the caterpillar was transferred to a salicin-free diet. We propose that toxicity is a more significant barrier to dietary adaptation than ‘bitterness’ in this insect.
8
Büsse, Sebastian, Fabian Bäumler e Stanislav N. Gorb. "Functional morphology of the raptorial forelegs in Mantispa styriaca (Insecta: Neuroptera)". Zoomorphology 140, n. 2 (12 aprile 2021): 231–41. http://dx.doi.org/10.1007/s00435-021-00524-6.
Testo completoAbstract (sommario):
AbstractThe insect leg is a multifunctional device, varying tremendously in form and function within Insecta: from a common walking leg, to burrowing, swimming or jumping devices, up to spinning apparatuses or tools for prey capturing. Raptorial forelegs, as predatory striking and grasping devices, represent a prominent example for convergent evolution within insects showing strong morphological and behavioural adaptations for a lifestyle as an ambush predator. However, apart from praying mantises (Mantodea)—the most prominent example of this lifestyle—the knowledge on morphology, anatomy, and the functionality of insect raptorial forelegs, in general, is scarce. Here, we show a detailed morphological description of raptorial forelegs of Mantispa styriaca (Neuroptera), including musculature and the material composition in their cuticle; further, we will discuss the mechanism of the predatory strike. We could confirm all 15 muscles previously described for mantis lacewings, regarding extrinsic and intrinsic musculature, expanding it for one important new muscle—M24c. Combining the information from all of our results, we were able to identify a possible catapult mechanism (latch-mediated spring actuation system) as a driving force of the predatory strike, never proposed for mantis lacewings before. Our results lead to a better understanding of the biomechanical aspects of the predatory strike in Mantispidae. This study further represents a starting point for a comprehensive biomechanical investigation of the convergently evolved raptorial forelegs in insects.
9
Blanke, Alexander, Peter T. Rühr, Rajmund Mokso, Pablo Villanueva, Fabian Wilde, Marco Stampanoni, Kentaro Uesugi, Ryuichiro Machida e Bernhard Misof. "Structural mouthpart interaction evolved already in the earliest lineages of insects". Proceedings of the Royal Society B: Biological Sciences 282, n. 1812 (7 agosto 2015): 20151033. http://dx.doi.org/10.1098/rspb.2015.1033.
Testo completoAbstract (sommario):
In butterflies, bees, flies and true bugs specific mouthparts are in close contact or even fused to enable piercing, sucking or sponging of particular food sources. The common phenomenon behind these mouthpart types is a complex composed of several consecutive mouthparts which structurally interact during food uptake. The single mouthparts are thus only functional in conjunction with other adjacent mouthparts, which is fundamentally different to biting–chewing. It is, however, unclear when structural mouthpart interaction (SMI) evolved since this principle obviously occurred multiple times independently in several extant and extinct winged insect groups. Here, we report a new type of SMI in two of the earliest wingless hexapod lineages—Diplura and Collembola. We found that the mandible and maxilla interact with each other via an articulatory stud at the dorsal side of the maxillary stipes, and they are furthermore supported by structures of the hypopharynx and head capsule. These interactions are crucial stabilizing elements during food uptake. The presence of SMI in these ancestrally wingless insects, and its absence in those crustacean groups probably ancestral to insects, indicates that SMI is a groundplan apomorphy of insects. Our results thus contradict the currently established view of insect mouthpart evolution that biting–chewing mouthparts without any form of SMI are the ancestral configuration. Furthermore, SMIs occur in the earliest insects in a high anatomical variety. SMIs in stemgroup representatives of insects may have triggered efficient exploitation and fast adaptation to new terrestrial food sources much earlier than previously supposed.
10
Bai, Xiaodong, Jianhua Zhang, Adam Ewing, Sally A. Miller, Agnes Jancso Radek, Dmitriy V. Shevchenko, Kiryl Tsukerman et al. "Living with Genome Instability: the Adaptation of Phytoplasmas to Diverse Environments of Their Insect and Plant Hosts". Journal of Bacteriology 188, n. 10 (15 maggio 2006): 3682–96. http://dx.doi.org/10.1128/jb.188.10.3682-3696.2006.
Testo completoAbstract (sommario):
ABSTRACT Phytoplasmas (“Candidatus Phytoplasma,” class Mollicutes) cause disease in hundreds of economically important plants and are obligately transmitted by sap-feeding insects of the order Hemiptera, mainly leafhoppers and psyllids. The 706,569-bp chromosome and four plasmids of aster yellows phytoplasma strain witches' broom (AY-WB) were sequenced and compared to the onion yellows phytoplasma strain M (OY-M) genome. The phytoplasmas have small repeat-rich genomes. This comparative analysis revealed that the repeated DNAs are organized into large clusters of potential mobile units (PMUs), which contain tra5 insertion sequences (ISs) and genes for specialized sigma factors and membrane proteins. So far, these PMUs appear to be unique to phytoplasmas. Compared to mycoplasmas, phytoplasmas lack several recombination and DNA modification functions, and therefore, phytoplasmas may use different mechanisms of recombination, likely involving PMUs, for the creation of variability, allowing phytoplasmas to adjust to the diverse environments of plants and insects. The irregular GC skews and the presence of ISs and large repeated sequences in the AY-WB and OY-M genomes are indicative of high genomic plasticity. Nevertheless, segments of ∼250 kb located between the lplA and glnQ genes are syntenic between the two phytoplasmas and contain the majority of the metabolic genes and no ISs. AY-WB appears to be further along in the reductive evolution process than OY-M. The AY-WB genome is ∼154 kb smaller than the OY-M genome, primarily as a result of fewer multicopy sequences, including PMUs. Furthermore, AY-WB lacks genes that are truncated and are part of incomplete pathways in OY-M.
11
Danks, H. V. "How aquatic insects live in cold climates". Canadian Entomologist 139, n. 4 (agosto 2007): 443–71. http://dx.doi.org/10.4039/n06-100.
Testo completoAbstract (sommario):
AbstractIn cold climates most aquatic habitats are frozen for many months. Nevertheless, even in such regions the conditions in different types of habitat, in different parts of one habitat, and from one year to the next can vary considerably; some water bodies even allow winter growth. Winter cold and ice provide challenges for aquatic insects, but so do high spring flows, short, cool summers, and unpredictable conditions. General adaptations to cope with these constraints, depending on species and habitat, include the use of widely available foods, increased food range, prolonged development (including development lasting more than one year per generation), programmed life cycles with diapause and other responses to environmental cues (often enforcing strict univoltinism), and staggered development. Winter conditions may be anticipated not only by diapause and related responses but also by movement for the winter to terrestrial habitats, to less severe aquatic habitats, or to different parts of the same habitat, and by construction of shelters. Winter itself is met by various types of cold hardiness, including tolerance of freezing in at least some species, especially chironomid midges, and supercooling even when surrounded by ice in others. Special cocoons provide protection in some species. A few species move during winter or resist anoxia beneath ice. Spring challenges of high flows and ice scour may be withstood or avoided by wintering in less severe habitats, penetrating the substrate, or delaying activity until after peak flow. However, where possible species emerge early in the spring to compensate for the shortness of the summer season, a trait enhanced (at least in some lentic habitats) by choosing overwintering sites that warm up first in spring. Relatively low summer temperatures are offset by development at low temperatures, by selection of warm habitats and microhabitats, and in adults by thermoregulation and modified mating activity. Notwithstanding the many abiotic constraints in cold climates, aquatic communities are relatively diverse, though dominated by taxa that combine traits such as cold adaptation with use of the habitats and foods that are most widely available and most favourable. Consequently, except in the most severe habitats, food chains and community structure are complex even at high latitudes and elevations, including many links between aquatic and terrestrial habitats. Despite the complex involvement of aquatic insects in these cold-climate ecosystems, we know relatively little about the physiological and biochemical basis of their cold hardiness and its relationship to habitat conditions, especially compared with information about terrestrial species from the same regions.
12
Buckley, Thomas R., Dilini Attanayake e Sven Bradler. "Extreme convergence in stick insect evolution: phylogenetic placement of the Lord Howe Island tree lobster". Proceedings of the Royal Society B: Biological Sciences 276, n. 1659 (16 dicembre 2008): 1055–62. http://dx.doi.org/10.1098/rspb.2008.1552.
Testo completoAbstract (sommario):
The ‘tree lobsters’ are an enigmatic group of robust, ground-dwelling stick insects (order Phasmatodea) from the subfamily Eurycanthinae, distributed in New Guinea, New Caledonia and associated islands. Its most famous member is the Lord Howe Island stick insect Dryococelus australis (Montrouzier), which was believed to have become extinct but was rediscovered in 2001 and is considered to be one of the rarest insects in the world. To resolve the evolutionary position of Dryococelus , we constructed a phylogeny from approximately 2.4 kb of mitochondrial and nuclear sequence data from representatives of all major phasmatodean lineages. Our data placed Dryococelus and the New Caledonian tree lobsters outside the New Guinean Eurycanthinae as members of an unrelated Australasian stick insect clade, the Lanceocercata. These results suggest a convergent origin of the ‘tree lobster’ body form. Our reanalysis of tree lobster characters provides additional support for our hypothesis of convergent evolution. We conclude that the phenotypic traits leading to the traditional classification are convergent adaptations to ground-living behaviour. Our molecular dating analyses indicate an ancient divergence (more than 22 Myr ago) between Dryococelus and its Australian relatives. Hence, Dryococelus represents a long-standing separate evolutionary lineage within the stick insects and must be regarded as a key taxon to protect with respect to phasmatodean diversity.
13
Drès, Michele, e James Mallet. "Host races in plant–feeding insects and their importance in sympatric speciation". Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 357, n. 1420 (29 aprile 2002): 471–92. http://dx.doi.org/10.1098/rstb.2002.1059.
Testo completoAbstract (sommario):
The existence of a continuous array of sympatric biotypes—from polymorphisms, through ecological or host races with increasing reproductive isolation, to good species—can provide strong evidence for a continuous route to sympatric speciation via natural selection. Host races in plant–feeding insects, in particular, have often been used as evidence for the probability of sympatric speciation. Here, we provide verifiable criteria to distinguish host races from other biotypes: in brief, host races are genetically differentiated, sympatric populations of parasites that use different hosts and between which there is appreciable gene flow. We recognize host races as kinds of species that regularly exchange genes with other species at a rate of more than ca . 1% per generation, rather than as fundamentally distinct taxa. Host races provide a convenient, although admittedly somewhat arbitrary intermediate stage along the speciation continuum. They are a heuristic device to aid in evaluating the probability of speciation by natural selection, particularly in sympatry. Speciation is thereby envisaged as having two phases: (i) the evolution of host races from within polymorphic, panmictic populations; and (ii) further reduction of gene flow between host races until the diverging populations can become generally accepted as species. We apply this criterion to 21 putative host race systems. Of these, only three are unambiguously classified as host races, but a further eight are strong candidates that merely lack accurate information on rates of hybridization or gene flow. Thus, over one–half of the cases that we review are probably or certainly host races, under our definition. Our review of the data favours the idea of sympatric speciation via host shift for three major reasons: (i) the evolution of assortative mating as a pleiotropic by–product of adaptation to a new host seems likely, even in cases where mating occurs away from the host; (ii) stable genetic differences in half of the cases attest to the power of natural selection to maintain multilocus polymorphisms with substantial linkage disequilibrium, in spite of probable gene flow; and (iii) this linkage disequilibrium should permit additional host adaptation, leading to further reproductive isolation via pleiotropy, and also provides conditions suitable for adaptive evolution of mate choice (reinforcement) to cause still further reductions in gene flow. Current data are too sparse to rule out a cryptic discontinuity in the apparently stable sympatric route from host–associated polymorphism to host–associated species, but such a hiatus seems unlikely on present evidence. Finally, we discuss applications of an understanding of host races in conservation and in managing adaptation by pests to control strategies, including those involving biological control or transgenic parasite–resistant plants.
14
Danks, H. V. "The elements of seasonal adaptations in insects". Canadian Entomologist 139, n. 1 (febbraio 2007): 1–44. http://dx.doi.org/10.4039/n06-048.
Testo completoAbstract (sommario):
AbstractThe many components of seasonal adaptations in insects are reviewed, especially from the viewpoint of aspects that must be studied in order to understand the structure and purposes of the adaptations. Component responses include dispersal, habitat selection, habitat modification, resistance to cold, dryness, and food limitation, trade-offs, diapause, modifications of developmental rate, sensitivity to environmental signals, life-cycle patterns including multiple alternatives in one species, and types of variation in phenology and development. Spatial, temporal, and resource elements of the environment are also reviewed, as are environmental signals, supporting the conclusion that further understanding of all of these seasonal responses requires detailed simultaneous study of the natural environments that drive the patterns of response.
15
Engsontia, Patamarerk, Unitsa Sangket, Wilaiwan Chotigeat e Chutamas Satasook. "Molecular Evolution of the Odorant and Gustatory Receptor Genes in Lepidopteran Insects: Implications for Their Adaptation and Speciation". Journal of Molecular Evolution 79, n. 1-2 (20 luglio 2014): 21–39. http://dx.doi.org/10.1007/s00239-014-9633-0.
Testo completo
16
Rolff, Jens, Paul R. Johnston e Stuart Reynolds. "Complete metamorphosis of insects". Philosophical Transactions of the Royal Society B: Biological Sciences 374, n. 1783 (26 agosto 2019): 20190063. http://dx.doi.org/10.1098/rstb.2019.0063.
Testo completoAbstract (sommario):
The majority of described hexapod species are holometabolous insects, undergoing an extreme form of metamorphosis with an intercalated pupal stage between the larva and adult, in which organs and tissues are extensively remodelled and in some cases completely rebuilt. Here, we review how and why this developmental strategy has evolved. While there are many theories explaining the evolution of metamorphosis, many of which fit under the hypothesis of decoupling of life stages, there are few clear adaptive hypotheses on why complete metamorphosis evolved. We propose that the main adaptive benefit of complete metamorphosis is decoupling between growth and differentiation. This facilitates the exploitation of ephemeral resources and enhances the probability of the metamorphic transition escaping developmental size thresholds. The evolution of complete metamorphosis comes at the cost of exposure to predators, parasites and pathogens during pupal life and requires specific adaptations of the immune system at this time. Moreover, metamorphosis poses a challenge for the maintenance of symbionts and the gut microbiota, although it may also offer the benefit of allowing an extensive change in microbiota between the larval and adult stages. The regulation of metamorphosis by two main players, ecdysone and juvenile hormone, and the related signalling cascades are now relatively well understood. The mechanics of metamorphosis have recently been studied in detail because of the advent of micro-CT and research into the role of cell death in remodelling tissues and organs. We support the argument that the adult stage must necessarily have preceded the larval form of the insect. We do not resolve the still contentious question of whether the larva of insects in general originated through the modification of existing preadult forms or through heterochrony as a modified embryonic stage (pronymph), nor whether the holometabolous pupa arose as a modified hemimetabolous final stage larva. This article is part of the theme issue ‘The evolution of complete metamorphosis’.
17
Danks, H. V. "LONG LIFE CYCLES IN INSECTS". Canadian Entomologist 124, n. 1 (febbraio 1992): 167–87. http://dx.doi.org/10.4039/ent124167-1.
Testo completoAbstract (sommario):
AbstractSeveral insect species have life cycles that last more than 1 year, because of very slow growth, repeated or prolonged dormancies, or very long lived adults. These long life cycles are correlated with environmental adversities, such as cold or unpredictable temperatures, patchy, unreliable or low quality food supplies, and natural enemies, as well as with some other properties such as large size. Long life cycles are most prevalent when several of these factors are present simultaneously. Adversities tend to prolong the life cycle of all individuals in the population, whereas unpredictability tends to extend the life cycle of only some individuals. Extreme extensions, such as diapause for more than 10 years, usually affect only a very small fraction of the population. Modest extensions, such as development over 2 years, prolonged dormancy for one additional adverse season, cohort-splitting between 1- and 2-year life cycles, and oviposition over two seasons, are relatively common. Insects with long life cycles provide insights into the nature of adaptations to adverse and unpredictable conditions, and also provide useful material for the analysis of questions related to population and community structure.
18
Chen, Yolanda H., e Sean D. Schoville. "Editorial overview: Ecology: Ecological adaptation in agroecosystems: novel opportunities to integrate evolutionary biology and agricultural entomology". Current Opinion in Insect Science 26 (aprile 2018): iv—viii. http://dx.doi.org/10.1016/j.cois.2018.03.003.
Testo completo
19
Farisenkov, Sergey E., Nadejda A. Lapina, Pyotr N. Petrov e Alexey A. Polilov. "Extraordinary flight performance of the smallest beetles". Proceedings of the National Academy of Sciences 117, n. 40 (21 settembre 2020): 24643–45. http://dx.doi.org/10.1073/pnas.2012404117.
Testo completoAbstract (sommario):
Size is a key to locomotion. In insects, miniaturization leads to fundamental changes in wing structure and kinematics, making the study of flight in the smallest species important for basic biology and physics, and, potentially, for applied disciplines. However, the flight efficiency of miniature insects has never been studied, and their speed and maneuverability have remained unknown. We report a comparative study of speeds and accelerations in the smallest free-living insects, featherwing beetles (Coleoptera: Ptiliidae), and in larger representatives of related groups of Staphylinoidea. Our results show that the average and maximum flight speeds of larger ptiliids are extraordinarily high and comparable to those of staphylinids that have bodies 3 times as long. This is one of the few known exceptions to the “Great Flight Diagram,” according to which the flight speed of smaller organisms is generally lower than that of larger ones. The horizontal acceleration values recorded in Ptiliidae are almost twice as high as even in Silphidae, which are more than an order of magnitude larger. High absolute and record-breaking relative flight characteristics suggest that the unique morphology and kinematics of the ptiliid wings are effective adaptations to flight at low Reynolds numbers. These results are important for understanding the evolution of body size and flight in insects and pose a challenge to designers of miniature biomorphic aircraft.
20
Danks, H. V. "Short life cycles in insects and mites". Canadian Entomologist 138, n. 4 (agosto 2006): 407–63. http://dx.doi.org/10.4039/n06-803.
Testo completoAbstract (sommario):
AbstractUnder favourable conditions some species of insects and mites complete development very quickly. This paper considers species with a mean minimum generation time of 15 days or less and tabulates developmental data for many sample species. Such species belong chiefly to a limited number of taxa of small size, notably aphids and several families of mites and parasitoid Hymenoptera. Characteristics of these taxa are reviewed. Even in families containing many species with rapid life cycles, normally many other species lack such rapid development. Very short life cycles depend on phylogeny, strain, rapid development in all stages, small size, rich food, and other habitat features including high temperatures. Within this framework, life cycles are accelerated by reducing elements requiring the investment of resources (size, fecundity, longevity, structural complexity), eliminating instars and even life stages, accelerating development (through lower requirements especially of heat, heat gain by adaptations such as basking, and rapid reproduction), and choosing the most suitable habitats and microhabitats from those available. Mean minimum generation times in insects and mites with coincident adaptations of this sort can be as short as 4 days. Notwithstanding the advantages of rapid development in maximizing the intrinsic rate of natural increase (and hence fitness), most species cannot achieve the highest rates of development. They are constrained not only by resources and intrinsic physiological or phylogenetic patterns but also by variability of conditions and seasonality that can be survived only by interpolating delays or resistant stages.
21
Raymond, M., C. Chevillon, T. Guillemaud, T. Lenormand e N. Pasteur. "An overview of the evolution of overproduced esterases in the mosquito Culex pipiens". Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 353, n. 1376 (29 ottobre 1998): 1707–11. http://dx.doi.org/10.1098/rstb.1998.0322.
Testo completoAbstract (sommario):
Insecticide resistance genes have developed in a wide variety of insects in response to heavy chemical application. Few of these examples of adaptation in response to rapid environmental change have been studied both at the population level and at the gene level. One of these is the evolution of the overproduced esterases that are involved in resistance to organophosphate insecticides in the mosquito Culex pipiens . At the gene level, two genetic mechanisms are involved in esterase overproduction, namely gene amplification and gene regulation. At the population level, the co–occurrence of the same amplified allele in distinct geographic areas is best explained by the importance of passive transportation at the worldwide scale. The long–term monitoring of a population of mosquitoes in southern France has enabled a detailed study to be made of the evolution of resistance genes on a local scale, and has shown that a resistance gene with a lower cost has replaced a former resistance allele with a higher cost.
22
Humble, Leland M. "Overwintering adaptations in Arctic sawflies (Hymenoptera: Tenthredinidae) and their parasitoids: cold tolerance". Canadian Entomologist 138, n. 1 (febbraio 2006): 59–71. http://dx.doi.org/10.4039/n05-804.
Testo completoAbstract (sommario):
AbstractAlthough the extreme winter conditions of Arctic habitats are considered to be important determinants of the faunal composition of Arctic regions, the overwintering biology of most Arctic insects is unknown. A significant proportion of the insect fauna at high latitudes are hymenopterans, yet little information is available on their overwintering strategies. In this study I examined the overwintering strategies of willow gall-forming and catkin-feeding nematine sawflies and their parasitoids. All sawfly species overwintered as prepupae, were freezing-tolerant, and survived exposure to −50 °C. Freezing at high subzero temperatures was initiated by ice nucleators associated with the posterior hind gut wall. Heterogeneity of overwintering habitats with respect to temperature was not a determinant of the overwintering success of these Arctic sawflies. Divergent overwintering mechanisms were evident in the sawfly parasitoid taxa. Endoparasitoid larvae, like their sawfly hosts, were freezing-tolerant. Freezing of immature, feeding endoparasitoid larvae occurred at the freezing point of the host prepupa and was a consequence of the inoculation of the endoparasitoids' fluid compartments by ice crystals growing in the host hemolymph. Peculiarities in the structure of the endoparasitoid larval gut suggest that the site of nucleation is across the gut wall. Outside their hosts, however, endoparasitoid larvae can supercool extensively, and their tolerance of extremely low temperatures is similar to that of their hosts. Overwintering strategies adopted by the ectoparasitoids were also diverse, with both freezing-tolerant and freezing-intolerant species present in the parasitoid community. Freezing-intolerant species could not survive winter temperatures in the field in the absence of an insulating layer of snow.
23
Aiello, Brett R., Milton Tan, Usama Bin Sikandar, Alexis J. Alvey, Burhanuddin Bhinderwala, Katalina C. Kimball, Jesse R. Barber, Chris A. Hamilton, Akito Y. Kawahara e Simon Sponberg. "Adaptive shifts underlie the divergence in wing morphology in bombycoid moths". Proceedings of the Royal Society B: Biological Sciences 288, n. 1956 (4 agosto 2021): 20210677. http://dx.doi.org/10.1098/rspb.2021.0677.
Testo completoAbstract (sommario):
The evolution of flapping flight is linked to the prolific success of insects. Across Insecta, wing morphology diversified, strongly impacting aerodynamic performance. In the presence of ecological opportunity, discrete adaptive shifts and early bursts are two processes hypothesized to give rise to exceptional morphological diversification. Here, we use the sister-families Sphingidae and Saturniidae to answer how the evolution of aerodynamically important traits is linked to clade divergence and through what process(es) these traits evolve. Many agile Sphingidae evolved hover feeding behaviours, while adult Saturniidae lack functional mouth parts and rely on a fixed energy budget as adults. We find that Sphingidae underwent an adaptive shift in wing morphology coincident with life history and behaviour divergence, evolving small high aspect ratio wings advantageous for power reduction that can be moved at high frequencies, beneficial for flight control. By contrast, Saturniidae, which do not feed as adults, evolved large wings and morphology which surprisingly does not reduce aerodynamic power, but could contribute to their erratic flight behaviour, aiding in predator avoidance. We suggest that after the evolution of flapping flight, diversification of wing morphology can be potentiated by adaptative shifts, shaping the diversity of wing morphology across insects.
24
Salachan, Paul Vinu, Jesper Givskov Sørensen e Heidi Joan Maclean. "What can physiological capacity and behavioural choice tell us about thermal adaptation?" Biological Journal of the Linnean Society 132, n. 1 (10 novembre 2020): 44–52. http://dx.doi.org/10.1093/biolinnean/blaa155.
Testo completoAbstract (sommario):
Abstract To date, behavioural responses and their role in thermal adaptation have largely been overlooked in small ectotherms. Here, we measure reproductive output using four adult acclimation temperatures in Drosophila melanogaster and quantify egg-laying at restricted temperatures (thermal capacity) and across a thermal gradient (thermal preference). We demonstrate that different conclusions about insect responses to changing environmental temperatures can be drawn based on whether individuals are temperature restricted or allowed a behavioural choice of temperature. When measuring physiological capacity at forced temperatures, we find an acclimation response to increasing temperatures. In contrast, when measuring behavioural choice, we find limited variation in thermal preference regardless of the acclimation temperature. Although flies are physiologically capable of increased performance at higher temperatures, these benefits might not be realized in heterogeneous environments. Our data serve as an example to illustrate why it is important to understand how behaviour and physiology contribute to thermal biology and, ultimately, the ecology of organisms. To do this, we should consider the behavioural avenues available to the organism when estimating ecologically relevant fitness consequences in varying thermal environments.
25
Jindra, Marek. "Where did the pupa come from? The timing of juvenile hormone signalling supports homology between stages of hemimetabolous and holometabolous insects". Philosophical Transactions of the Royal Society B: Biological Sciences 374, n. 1783 (26 agosto 2019): 20190064. http://dx.doi.org/10.1098/rstb.2019.0064.
Testo completoAbstract (sommario):
Insect metamorphosis boasts spectacular cases of postembryonic development when juveniles undergo massive morphogenesis before attaining the adult form and function; in moths or flies the larvae do not even remotely resemble their adult parents. A selective advantage of complete metamorphosis (holometaboly) is that within one species the two forms with different lifestyles can exploit diverse habitats. It was the environmental adaptation and specialization of larvae, primarily the delay and internalization of wing development, that eventually required an intermediate stage that we call a pupa. It is a long-held and parsimonious hypothesis that the holometabolous pupa evolved through modification of a final juvenile stage of an ancestor developing through incomplete metamorphosis (hemimetaboly). Alternative hypotheses see the pupa as an equivalent of all hemimetabolous moulting cycles (instars) collapsed into one, and consider any preceding holometabolous larval instars free-living embryos stalled in development. Discoveries on juvenile hormone signalling that controls metamorphosis grant new support to the former hypothesis deriving the pupa from a final pre-adult stage. The timing of expression of genes that repress and promote adult development downstream of hormonal signals supports homology between postembryonic stages of hemimetabolous and holometabolous insects. This article is part of the theme issue ‘The evolution of complete metamorphosis’.
26
Lighton, J. R. B., D. A. Garrigan, F. D. Duncan e R. A. Johnson. "SPIRACULAR CONTROL OF RESPIRATORY WATER LOSS IN FEMALE ALATES OF THE HARVESTER ANT POGONOMYRMEX RUGOSUS". Journal of Experimental Biology 179, n. 1 (1 giugno 1993): 233–44. http://dx.doi.org/10.1242/jeb.179.1.233.
Testo completoAbstract (sommario):
It has been suggested that the discontinuous ventilation cycle (DVC) observed in many insects, including all ants described to date, is an adaptation to reduce respiratory water loss. To test this hypothesis, it is necessary to measure respiratory water loss as a percentage of total water loss and to estimate what sustained rates of water loss would be in the absence of spiracular control. We used two independent techniques to measure real-time water loss rates in female alates of Pogonomyrmex rugosus. The first measured water vapor emission and CO2 production simultaneously using dual- wavelength infrared absorbance analysis (DWIRAA). The second measured water loss gravimetrically. Real-time measurement allowed the separation of cuticular water loss rates (interburst) from water loss rates during the ventilation phase (burst) of the DVC. Cuticular permeability of P. rugosus female alates was only 27 ng h-1 cm-2 Pa-1, one-third of that reported for workers of the same species and the lowest yet reported for ants. Partly because of this low cuticular permeability, respiratory water loss represented a greater percentage of overall water loss (13 %) than has generally been reported for other insects. The DWIRAA and gravimetric techniques gave equivalent results. Peak rates of water loss during the burst phase were 2.8-fold higher than cuticular water loss rates alone (7.68 mg g-1 h-1 versus 2.77 mg g-1 h-1 at 25°C). This is a conservative estimate of water loss rates in the absence of spiracular control. Contrary to findings in certain other insects that suggest a negligible role for respiratory water loss, we find that, in an insect that employs the DVC and has low cuticular permeability, overall water loss rates rise several-fold in the absence of direct spiracular control. Our findings lend strong support to the water conservation hypothesis for the role of the DVC. In at least some insects, respiratory water loss rates can reach magnitudes significant enough, relative to other routes of water loss, for strong selective pressure to act on them.
27
Rolff, Jens, e Paul Schmid-Hempel. "Perspectives on the evolutionary ecology of arthropod antimicrobial peptides". Philosophical Transactions of the Royal Society B: Biological Sciences 371, n. 1695 (26 maggio 2016): 20150297. http://dx.doi.org/10.1098/rstb.2015.0297.
Testo completoAbstract (sommario):
Antimicrobial peptides (AMPs) are important elements of the innate immune defence in multicellular organisms that target and kill microbes. Here, we reflect on the various points that are raised by the authors of the 11 contributions to a special issue of Philosophical Transactions on the ‘evolutionary ecology of arthropod antimicrobial peptides'. We see five interesting topics emerging. (i) AMP genes in insects, and perhaps in arthropods more generally, evolve much slower than most other immune genes. One explanation refers to the constraints set by AMPs being part of a finely tuned defence system. A new view argues that AMPs are under strong stabilizing selection. Regardless, this striking observation still invites many more questions than have been answered so far. (ii) AMPs almost always are expressed in combinations and sometimes show expression patterns that are dependent on the infectious agent. While it is often assumed that this can be explained by synergistic interactions, such interactions have rarely been demonstrated and need to be studied further. Moreover, how to define synergy in the first place remains difficult and needs to be addressed. (iii) AMPs play a very important role in mediating the interaction between a host and its mutualistic or commensal microbes. This has only been studied in a very small number of (insect) species. It has become clear that the very same AMPs play different roles in different situations and hence are under concurrent selection. (iv) Different environments shape the physiology of organisms; especially the host-associated microbial communities should impact on the evolution host AMPs. Studies in social insects and some organisms from extreme environments seem to support this notion, but, overall, the evidence for adaptation of AMPs to a given environment is scant. (v) AMPs are considered or already developed as new drugs in medicine. However, bacteria can evolve resistance to AMPs. Therefore, in the light of our limited understanding of AMP evolution in the natural context, and also the very limited understanding of the evolution of resistance against AMPs in bacteria in particular, caution is recommended. What is clear though is that study of the ecology and evolution of AMPs in natural systems could inform many of these outstanding questions, including those related to medical applications and pathogen control. This article is part of the themed issue ‘Evolutionary ecology of arthropod antimicrobial peptides’.
28
Mans, Ben J., e Albert W. H. Neitz. "Adaptation of ticks to a blood-feeding environment: evolution from a functional perspective". Insect Biochemistry and Molecular Biology 34, n. 1 (gennaio 2004): 1–17. http://dx.doi.org/10.1016/j.ibmb.2003.09.002.
Testo completo
29
Keller, Laurent. "Adaptation and the genetics of social behaviour". Philosophical Transactions of the Royal Society B: Biological Sciences 364, n. 1533 (12 novembre 2009): 3209–16. http://dx.doi.org/10.1098/rstb.2009.0108.
Testo completoAbstract (sommario):
In recent years much progress has been made towards understanding the selective forces involved in the evolution of social behaviour including conflicts over reproduction among group members. Here, I argue that an important additional step necessary for advancing our understanding of the resolution of potential conflicts within insect societies is to consider the genetics of the behaviours involved. First, I discuss how epigenetic modifications of behaviour may affect conflict resolution within groups. Second, I review known natural polymorphisms of social organization to demonstrate that a lack of consideration of the genetic mechanisms involved may lead to erroneous explanations of the adaptive significance of behaviour. Third, I suggest that, on the basis of recent genetic studies of sexual conflict in Drosophila , it is necessary to reconsider the possibility of within-group manipulation by means of chemical substances (i.e. pheromones). Fourth, I address the issue of direct versus indirect genetic effects, which is of particular importance for the study of behaviour in social groups. Fifth, I discuss the issue of how a genetic influence on dominance hierarchies and reproductive division of labour can have secondary effects, for example in the evolution of promiscuity. Finally, because the same sets of genes (e.g. those implicated in chemical signalling and the responses that are triggered) may be used even in species as divergent as ants, cooperative breeding birds and primates, an integration of genetic mechanisms into the field of social evolution may also provide unifying ideas.
30
Grodnitsky, D. L., e P. P. Morozov. "VORTEX FORMATION DURING TETHERED FLIGHT OF FUNCTIONALLY AND MORPHOLOGICALLY TWO-WINGED INSECTS, INCLUDING EVOLUTIONARY CONSIDERATIONS ON INSECT FLIGHT". Journal of Experimental Biology 182, n. 1 (1 settembre 1993): 11–40. http://dx.doi.org/10.1242/jeb.182.1.11.
Testo completoAbstract (sommario):
Tethered flight of six insect species (two pentatomid bugs, a moth, a butterfly, a muscid fly and a crane fly) was studied using several modifications of a dust flow visualization procedure. The spatial structure of the near vortex wake of flying specimens was reconstructed on the basis of two- dimensional flow pictures. The dynamics of the wake was followed during a stroke cycle, revealing interspecific differences in vortex formation. It is suggested that insects create a single vortex ring during each stroke. Therefore, the hypothesis of double vortex chains advanced by Brodsky is not verified. The same is true of the jet hypothesis of Bocharova-Messner. While pronating at the top of their trajectory, the flapping wings throw air masses off their lower surfaces, but there is not a jet from between their upper sides. Flow separation from leading edges was found to be a rare phenomenon, taking place irregularly during the stroke cycle. That is why, contrary to widespread theoretical expectations, the Weis-Fogh fling mechanism is not likely to contain a leading edge separation bubble, which must follow stalling at the front part of the wings. It is suggested that flying animals possess special mechanisms for extracting energy back from the near vortex wake. Some hypothetical adaptations for such an extraction in insects are put forward. Possible pathways for the evolution of insect flight are described.
31
Grüter, Christoph, Evelien Jongepier e Susanne Foitzik. "Insect societies fight back: the evolution of defensive traits against social parasites". Philosophical Transactions of the Royal Society B: Biological Sciences 373, n. 1751 (4 giugno 2018): 20170200. http://dx.doi.org/10.1098/rstb.2017.0200.
Testo completoAbstract (sommario):
Insect societies face many social parasites that exploit their altruistic behaviours or their resources. Due to the fitness costs these social parasites incur, hosts have evolved various behavioural, chemical, architectural and morphological defence traits. Similar to bacteria infecting multicellular hosts, social parasites have to successfully go through several steps to exploit their hosts. Here, we review how social insects try to interrupt this sequence of events. They can avoid parasite contact by choosing to nest in parasite-free locales or evade attacks by adapting their colony structure. Once social parasites attack, hosts attempt to detect them, which can be facilitated by adjustments in colony odour. If social parasites enter the nest, hosts can either aggressively defend their colony or take their young and flee. Nest structures are often shaped to prevent social parasite invasion or to safeguard host resources. Finally, if social parasites successfully establish themselves in host nests, hosts can rebel by killing the parasite brood or by reproducing in the parasites' presence. Hosts of social parasites can therefore develop multiple traits, leading to the evolution of complex defence portfolios of co-dependent traits. Social parasites can respond to these multi-level defences with counter-adaptations, potentially leading to geographical mosaics of coevolution. This article is part of the Theo Murphy meeting issue ‘Evolution of pathogen and parasite avoidance behaviours’.
32
Qu, Zhe, William G. Bendena, Wenyan Nong, Kenneth W. Siggens, Fernando G. Noriega, Zhen-peng Kai, Yang-yang Zang et al. "MicroRNAs regulate the sesquiterpenoid hormonal pathway in Drosophila and other arthropods". Proceedings of the Royal Society B: Biological Sciences 284, n. 1869 (13 dicembre 2017): 20171827. http://dx.doi.org/10.1098/rspb.2017.1827.
Testo completoAbstract (sommario):
Arthropods comprise the majority of all described animal species, and understanding their evolution is a central question in biology. Their developmental processes are under the precise control of distinct hormonal regulators, including the sesquiterpenoids juvenile hormone (JH) and methyl farnesoate. The control of the synthesis and mode of action of these hormones played important roles in the evolution of arthropods and their adaptation to diverse habitats. However, the precise roles of non-coding RNAs, such as microRNAs (miRNAs), controlling arthropod hormonal pathways are unknown. Here, we investigated the miRNA regulation of the expression of the juvenile hormone acid methyltransferase gene ( JHAMT ), which encodes a rate-determining sesquiterpenoid biosynthetic enzyme. Loss of function of the miRNA bantam in the fly Drosophila melanogaster increased JHAMT expression, while overexpression of the bantam repressed JHAMT expression and resulted in pupal lethality. The male genital organs of the pupae were malformed, and exogenous sesquiterpenoid application partially rescued the genital deformities. The role of the bantam in the regulation of sesquiterpenoid biosynthesis was validated by transcriptomic, qPCR and hormone titre (JHB3 and JH III) analyses. In addition, we found a conserved set of miRNAs that interacted with JHAMT , and the sesquiterpenoid receptor methoprene-tolerant ( Met ) in different arthropod lineages, including insects (fly, mosquito and beetle), crustaceans (water flea and shrimp), myriapod (centipede) and chelicerate (horseshoe crab). This suggests that these miRNAs might have conserved roles in the post-transcriptional regulation of genes in sesquiterpenoid pathways across the Panarthropoda. Some of the identified lineage-specific miRNAs are potential targets for the development of new strategies in aquaculture and agricultural pest control.
33
Finet, Cédric, Amélie Decaras, David Armisén e Abderrahman Khila. "The achaete–scute complex contains a single gene that controls bristle development in the semi-aquatic bugs". Proceedings of the Royal Society B: Biological Sciences 285, n. 1892 (28 novembre 2018): 20182387. http://dx.doi.org/10.1098/rspb.2018.2387.
Testo completoAbstract (sommario):
The semi-aquatic bugs (Heteroptera, Gerromorpha) conquered water surfaces worldwide and diversified to occupy puddles, ponds, streams, lakes, mangroves and even oceans. Critical to this lifestyle is the evolution of sets of hairs that allow these insects to maintain their body weight on the water surface and protect the animals against wetting and drowning. In addition, the legs of these insects are equipped with various grooming combs that are important for cleaning and tidying the hair layers for optimal functional efficiency. Here we show that the hairs covering the legs of water striders represent innervated bristles. Genomic and transcriptomic analyses revealed that in water striders the achaete–scute complex, known to control bristle development in flies, contains only the achaete–scute homologue ( ASH ) gene owing to the loss of the gene asense. Using RNA interference, we show that ASH plays a pivotal role in the development of both bristles and grooming combs in water striders. Our data suggest that the ASH locus may have contributed to the adaptation to water surface lifestyle through shaping the hydrophobic bristles that prevent water striders from wetting and allow them to exploit water surface tension.
34
Cao, Tianxin, Alyson Sujkowski, Tyler Cobb, Robert J. Wessells e Jian-Ping Jin. "The glutamic acid-rich–long C-terminal extension of troponin T has a critical role in insect muscle functions". Journal of Biological Chemistry 295, n. 12 (5 febbraio 2020): 3794–807. http://dx.doi.org/10.1074/jbc.ra119.012014.
Testo completoAbstract (sommario):
The troponin complex regulates the Ca2+ activation of myofilaments during striated muscle contraction and relaxation. Troponin genes emerged 500–700 million years ago during early animal evolution. Troponin T (TnT) is the thin-filament–anchoring subunit of troponin. Vertebrate and invertebrate TnTs have conserved core structures, reflecting conserved functions in regulating muscle contraction, and they also contain significantly diverged structures, reflecting muscle type- and species-specific adaptations. TnT in insects contains a highly-diverged structure consisting of a long glutamic acid–rich C-terminal extension of ∼70 residues with unknown function. We found here that C-terminally truncated Drosophila TnT (TpnT–CD70) retains binding of tropomyosin, troponin I, and troponin C, indicating a preserved core structure of TnT. However, the mutant TpnTCD70 gene residing on the X chromosome resulted in lethality in male flies. We demonstrate that this X-linked mutation produces dominant-negative phenotypes, including decreased flying and climbing abilities, in heterozygous female flies. Immunoblot quantification with a TpnT-specific mAb indicated expression of TpnT–CD70 in vivo and normal stoichiometry of total TnT in myofilaments of heterozygous female flies. Light and EM examinations revealed primarily normal sarcomere structures in female heterozygous animals, whereas Z-band streaming could be observed in the jump muscle of these flies. Although TpnT–CD70-expressing flies exhibited lower resistance to cardiac stress, their hearts were significantly more tolerant to Ca2+ overloading induced by high-frequency electrical pacing. Our findings suggest that the Glu-rich long C-terminal extension of insect TnT functions as a myofilament Ca2+ buffer/reservoir and is potentially critical to the high-frequency asynchronous contraction of flight muscles.
35
Deora, Tanvi, Amit Kumar Singh e Sanjay P. Sane. "Biomechanical basis of wing and haltere coordination in flies". Proceedings of the National Academy of Sciences 112, n. 5 (20 gennaio 2015): 1481–86. http://dx.doi.org/10.1073/pnas.1412279112.
Testo completoAbstract (sommario):
The spectacular success and diversification of insects rests critically on two major evolutionary adaptations. First, the evolution of flight, which enhanced the ability of insects to colonize novel ecological habitats, evade predators, or hunt prey; and second, the miniaturization of their body size, which profoundly influenced all aspects of their biology from development to behavior. However, miniaturization imposes steep demands on the flight system because smaller insects must flap their wings at higher frequencies to generate sufficient aerodynamic forces to stay aloft; it also poses challenges to the sensorimotor system because precise control of wing kinematics and body trajectories requires fast sensory feedback. These tradeoffs are best studied in Dipteran flies in which rapid mechanosensory feedback to wing motor system is provided by halteres, reduced hind wings that evolved into gyroscopic sensors. Halteres oscillate at the same frequency as and precisely antiphase to the wings; they detect body rotations during flight, thus providing feedback that is essential for controlling wing motion during aerial maneuvers. Although tight phase synchrony between halteres and wings is essential for providing proper timing cues, the mechanisms underlying this coordination are not well understood. Here, we identify specific mechanical linkages within the thorax that passively mediate both wing–wing and wing–haltere phase synchronization. We demonstrate that the wing hinge must possess a clutch system that enables flies to independently engage or disengage each wing from the mechanically linked thorax. In concert with a previously described gearbox located within the wing hinge, the clutch system enables independent control of each wing. These biomechanical features are essential for flight control in flies.
36
Pan, Yiou, Pengjun Xu, Xiaochun Zeng, Xuemei Liu e Qingli Shang. "Characterization of UDP-Glucuronosyltransferases and the Potential Contribution to Nicotine Tolerance in Myzus persicae". International Journal of Molecular Sciences 20, n. 15 (25 luglio 2019): 3637. http://dx.doi.org/10.3390/ijms20153637.
Testo completoAbstract (sommario):
Uridine diphosphate (UDP)-glycosyltransferases (UGTs) are major phase II detoxification enzymes involved in glycosylation of lipophilic endobiotics and xenobiotics, including phytoalexins. Nicotine, one of the most abundant secondary plant metabolites in tobacco, is highly toxic to herbivorous insects. Plant-herbivore competition is the major impetus for the evolution of large superfamilies of UGTs and other detoxification enzymes. However, UGT functions in green peach aphid (Myzus persicae) adaptation are unknown. In this study, we show that UGT inhibitors (sulfinpyrazone and 5-nitrouracil) significantly increased nicotine toxicity in M. persicae nicotianae, suggesting that UGTs may be involved in nicotine tolerance. In total, 101 UGT transcripts identified in the M. persicae genome/transcriptome were renamed according to the UGT Nomenclature Committee guidelines and grouped into 11 families, UGT329, UGT330, UGT339, UGT341–UGT345, and UGT348–UGT350, with UGT344 containing the most (57). Ten UGTs (UGT330A3, UGT339A2, UGT341A6, UGT342B3, UGT343C3, UGT344D5, UGT344D8, UGT348A3, UGT349A3, and UGT350A3) were highly expressed in M. persicae nicotianae compared to M. persicae sensu stricto. Knockdown of four UGTs (UGT330A3, UGT344D5, UGT348A3, and UGT349A3) significantly increased M. persicae nicotianae sensitivity to nicotine, suggesting that UGT expression in this subspecies may be associated with nicotine tolerance and thus host adaptation. This study reveals possible UGTs relevant to nicotine adaptation in tobacco-consuming M. persicae nicotianae, and the findings will facilitate further validation of the roles of these UGTs in nicotine tolerance.
37
Röder, Gregory, Martine Rahier e Russell E. Naisbit. "Counter-intuitive developmental plasticity induced by host quality". Proceedings of the Royal Society B: Biological Sciences 275, n. 1637 (15 gennaio 2008): 879–85. http://dx.doi.org/10.1098/rspb.2007.1649.
Testo completoAbstract (sommario):
Adaptation to different hosts plays a central role in the evolution of specialization and speciation in phytophagous insects and parasites, and our ability to experimentally rank hosts by their quality is critical to research to understand these processes. Here we provide a counter-intuitive example in which growth is faster on poor quality hosts. The leaf beetles Oreina elongata and Oreina cacaliae share their host plant with the rust Uromyces cacaliae . Larvae reared on infected Adenostyles alliariae show reduced growth rate, reduced maximum weight and longer development time. However, they normally respond adaptively to the rust's mid-season arrival. When switched during development from healthy to infected leaves, larvae accelerate growth and reduce development time, but pupate at lower body weight. In this novel plant–insect–fungus interaction, infection forms the cue to trade off life-history traits in order to complete development within the brief alpine summer. It represents a novel mode of developmental plasticity, which is likely to be found in other host–parasite systems whenever host quality deteriorates due to multiple infection or ageing. This phenotypic plasticity would modify competition after co-infection and the mutual selection imposed by hosts and parasites, and creates a paradoxical negative correlation between growth rate and environmental quality.
38
Grumet, Rebecca, James D. McCreight, Cecilia McGregor, Yiqun Weng, Michael Mazourek, Kathleen Reitsma, Joanne Labate, Angela Davis e Zhangjun Fei. "Genetic Resources and Vulnerabilities of Major Cucurbit Crops". Genes 12, n. 8 (7 agosto 2021): 1222. http://dx.doi.org/10.3390/genes12081222.
Testo completoAbstract (sommario):
The Cucurbitaceae family provides numerous important crops including watermelons (Citrullus lanatus), melons (Cucumis melo), cucumbers (Cucumis sativus), and pumpkins and squashes (Cucurbita spp.). Centers of domestication in Africa, Asia, and the Americas were followed by distribution throughout the world and the evolution of secondary centers of diversity. Each of these crops is challenged by multiple fungal, oomycete, bacterial, and viral diseases and insects that vector disease and cause feeding damage. Cultivated varieties are constrained by market demands, the necessity for climatic adaptations, domestication bottlenecks, and in most cases, limited capacity for interspecific hybridization, creating narrow genetic bases for crop improvement. This analysis of crop vulnerabilities examines the four major cucurbit crops, their uses, challenges, and genetic resources. ex situ germplasm banks, the primary strategy to preserve genetic diversity, have been extensively utilized by cucurbit breeders, especially for resistances to biotic and abiotic stresses. Recent genomic efforts have documented genetic diversity, population structure, and genetic relationships among accessions within collections. Collection size and accessibility are impacted by historical collections, current ability to collect, and ability to store and maintain collections. The biology of cucurbits, with insect-pollinated, outcrossing plants, and large, spreading vines, pose additional challenges for regeneration and maintenance. Our ability to address ongoing and future cucurbit crop vulnerabilities will require a combination of investment, agricultural, and conservation policies, and technological advances to facilitate collection, preservation, and access to critical Cucurbitaceae diversity.
39
Kong, Jacinta D., Ary A. Hoffmann e Michael R. Kearney. "Linking thermal adaptation and life-history theory explains latitudinal patterns of voltinism". Philosophical Transactions of the Royal Society B: Biological Sciences 374, n. 1778 (17 giugno 2019): 20180547. http://dx.doi.org/10.1098/rstb.2018.0547.
Testo completoAbstract (sommario):
Insect life cycles are adapted to a seasonal climate by expressing alternative voltinism phenotypes—the number of generations in a year. Variation in voltinism phenotypes along latitudinal gradients may be generated by developmental traits at critical life stages, such as eggs. Both voltinism and egg development are thermally determined traits, yet independently derived models of voltinism and thermal adaptation refer to the evolution of dormancy and thermal sensitivity of development rate, respectively, as independent influences on life history. To reconcile these models and test their respective predictions, we characterized patterns of voltinism and thermal response of egg development rate along a latitudinal temperature gradient using the matchstick grasshopper genus Warramaba . We found remarkably strong variation in voltinism patterns, as well as corresponding egg dormancy patterns and thermal responses of egg development. Our results show that the switch in voltinism along the latitudinal gradient was explained by the combined predictions of the evolution of voltinism and of thermal adaptation. We suggest that latitudinal patterns in thermal responses and corresponding life histories need to consider the evolution of thermal response curves within the context of seasonal temperature cycles rather than based solely on optimality and trade-offs in performance. This article is part of the theme issue ‘Physiological diversity, biodiversity patterns and global climate change: testing key hypotheses involving temperature and oxygen’.
40
Ro, AI, e DE Nilsson. "Pupil adjustments in the eye of the common backswimmer". Journal of Experimental Biology 198, n. 1 (1 gennaio 1995): 71–77. http://dx.doi.org/10.1242/jeb.198.1.71.
Testo completoAbstract (sommario):
The pupil mechanism in the acone apposition eye of the semi-aquatic common backswimmer Notonecta glauca (Hemiptera) was investigated with infrared reflectometry of the pseudopupil. This method allows non-invasive continuous measurements of pupil responses in the living animal. The dynamic range of the pupil sensitivity is about 7 log units during daytime and 6 log units at night. During the day, the sensitivity range of the pupil covers the normal daylight intensities in the animal's habitat, just under the water surface (I50=10(19.2) photons m-2 sr-1 s-1). At night, the sensitivity is 1 log unit lower (I50=10(20.2) photons m-2 sr-1 s-1), ensuring that the pupil is maximally open when light intensities are low. During daytime, light adaptation is completed in slightly less than 40 min, and dark adaptation takes approximately 50 min. The pupil response is only slightly slower at night. The speed of the response as well as the pupil sensitivity are dependent on the preceding adaptation history. An endogenous circadian rhythm determines the control range of the pupil aperture. However, the rhythm is easily disturbed, especially within a 3 h period before dusk and dawn. The results are compared with corresponding results from other insects with the same type of pupil mechanism.
41
Dobler, Susanne, Vera Wagschal, Niels Pietsch, Nadja Dahdouli, Fee Meinzer, Renja Romey-Glüsing e Kai Schütte. "New ways to acquire resistance: imperfect convergence in insect adaptations to a potent plant toxin". Proceedings of the Royal Society B: Biological Sciences 286, n. 1908 (7 agosto 2019): 20190883. http://dx.doi.org/10.1098/rspb.2019.0883.
Testo completoAbstract (sommario):
Evolution of insensitivity to the toxic effects of cardiac glycosides has become a model in the study of convergent evolution, as five taxonomic orders of insects use the same few similar amino acid substitutions in the otherwise highly conserved Na,K-ATPase α. We show here that insensitivity in pyrgomorphid grasshoppers evolved along a slightly divergent path. As in other lineages, duplication of the Na,K-ATPase α gene paved the way for subfunctionalization: one copy maintains the ancestral, sensitive state, while the other copy is resistant. Nonetheless, in contrast with all other investigated insects, the grasshoppers' resistant copy shows length variation by two amino acids in the first extracellular loop, the main part of the cardiac glycoside-binding pocket. RT-qPCR analyses confirmed that this copy is predominantly expressed in tissues exposed to the toxins, while the ancestral copy predominates in the nervous tissue. Functional tests with genetically engineered Drosophila Na,K-ATPases bearing the first extracellular loop of the pyrgomorphid genes showed the derived form to be highly resistant, while the ancestral state is sensitive. Thus, we report convergence in gene duplication and in the gene targets for toxin insensitivity; however, the means to the phenotypic end have been novel in pyrgomorphid grasshoppers.
42
Sriphirom, Paradee, Piyamas Nanork Sopaladawan, Komgrit Wongpakam e Pairot Pramual. "Molecular phylogeny of black flies in the Simulium tuberosum (Diptera: Simuliidae) species group in Thailand". Genome 57, n. 1 (gennaio 2014): 45–55. http://dx.doi.org/10.1139/gen-2013-0145.
Testo completoAbstract (sommario):
Black flies are medically and ecologically significant insects. They are also interesting from an evolutionary standpoint regarding the role of chromosomal change and ecological adaptation. In this study, molecular genetic markers based on multiple gene sequences were used to assess genetic diversity and to infer phylogenetic relationships for a group of cytologically highly diverse black flies of the Simulium tuberosum species group in Thailand. Ecological affinities of the species were also investigated. High levels of genetic diversity were found in cytological species complexes, S. tani and S. doipuiense, and also in S. rufibasis, which was cytologically nearly monomorphic. The results highlight the necessity of integrating multilevel markers for fully understanding black fly biodiversity. Phylogenetic relationships based on multiple gene sequences were consistent with an existing dendrogram inferred from cytological and morphological data. Simulium tani is the most distinctive taxa among the members of the S. tubersosum species group in Thailand based on its divergent morphological characters. Molecular data supported the monophyletic status of S. tani, S. weji, and S. yuphae, but S. doipuiense and S. rufibasis were polyphyletic, most likely due to incomplete lineage sorting and inadequate phylogenetic signals. Ecological analyses revealed that members of the S. tuberosum species group have clearly different ecological niches. The results thus supported previous views of the importance of ecology in black fly evolution.
43
Dyson, Carl J., e Michael A. D. Goodisman. "Gene Duplication in the Honeybee: Patterns of DNA Methylation, Gene Expression, and Genomic Environment". Molecular Biology and Evolution 37, n. 8 (3 aprile 2020): 2322–31. http://dx.doi.org/10.1093/molbev/msaa088.
Testo completoAbstract (sommario):
Abstract Gene duplication serves a critical role in evolutionary adaptation by providing genetic raw material to the genome. The evolution of duplicated genes may be influenced by epigenetic processes such as DNA methylation, which affects gene function in some taxa. However, the manner in which DNA methylation affects duplicated genes is not well understood. We studied duplicated genes in the honeybee Apis mellifera, an insect with a highly sophisticated social structure, to investigate whether DNA methylation was associated with gene duplication and genic evolution. We found that levels of gene body methylation were significantly lower in duplicate genes than in single-copy genes, implicating a possible role of DNA methylation in postduplication gene maintenance. Additionally, we discovered associations of gene body methylation with the location, length, and time since divergence of paralogous genes. We also found that divergence in DNA methylation was associated with divergence in gene expression in paralogs, although the relationship was not completely consistent with a direct link between DNA methylation and gene expression. Overall, our results provide further insight into genic methylation and how its association with duplicate genes might facilitate evolutionary processes and adaptation.
44
Meunier, Joël, e Mathias Kölliker. "Parental antagonism and parent–offspring co-adaptation interact to shape family life". Proceedings of the Royal Society B: Biological Sciences 279, n. 1744 (18 luglio 2012): 3981–88. http://dx.doi.org/10.1098/rspb.2012.1416.
Testo completoAbstract (sommario):
The family is an arena for conflicts between offspring, mothers and fathers that need resolving to promote the evolution of parental care and the maintenance of family life. Co-adaptation is known to contribute to the resolution of parent–offspring conflict over parental care by selecting for combinations of offspring demand and parental supply that match to maximize the fitness of family members. However, multiple paternity and differences in the level of care provided by mothers and fathers can generate antagonistic selection on offspring demand (mediated, for example, by genomic imprinting) and possibly hamper co-adaptation. While parent–offspring co-adaptation and parental antagonism are commonly considered two major processes in the evolution of family life, their co-occurrence and the evolutionary consequences of their joint action are poorly understood. Here, we demonstrate the simultaneous and entangled effects of these two processes on outcomes of family interactions, using a series of breeding experiments in the European earwig, Forficula auricularia , an insect species with uniparental female care. As predicted from parental antagonism, we show that paternally inherited effects expressed in offspring influence both maternal care and maternal investment in future reproduction. However, and as expected from the entangled effects of parental antagonism and co-adaptation, these effects critically depended on postnatal interactions with caring females and maternally inherited effects expressed in offspring. Our results demonstrate that parent–offspring co-adaptation and parental antagonism are entangled key drivers in the evolution of family life that cannot be fully understood in isolation.
45
Clutton-Brock, Tim. "Structure and function in mammalian societies". Philosophical Transactions of the Royal Society B: Biological Sciences 364, n. 1533 (12 novembre 2009): 3229–42. http://dx.doi.org/10.1098/rstb.2009.0120.
Testo completoAbstract (sommario):
Traditional interpretations of the evolution of animal societies have suggested that their structure is a consequence of attempts by individuals to maximize their inclusive fitness within constraints imposed by their social and physical environments. In contrast, some recent re-interpretations have argued that many aspects of social organization should be interpreted as group-level adaptations maintained by selection operating between groups or populations. Here, I review our current understanding of the evolution of mammalian societies, focusing, in particular, on the evolution of reproductive strategies in societies where one dominant female monopolizes reproduction in each group and her offspring are reared by other group members. Recent studies of the life histories of females in these species show that dispersing females often have little chance of establishing new breeding groups and so are likely to maximize their inclusive fitness by helping related dominants to rear their offspring. As in eusocial insects, increasing group size can lead to a progressive divergence in the selection pressures operating on breeders and helpers and to increasing specialization in their behaviour and life histories. As yet, there is little need to invoke group-level adaptations in order to account for the behaviour of individuals or the structure of mammalian groups.
46
Lindgren, B. S., e K. F. Raffa. "Evolution of tree killing in bark beetles (Coleoptera: Curculionidae): trade-offs between the maddening crowds and a sticky situation". Canadian Entomologist 145, n. 5 (11 giugno 2013): 471–95. http://dx.doi.org/10.4039/tce.2013.27.
Testo completoAbstract (sommario):
AbstractBark beetles (Coleoptera: Curculionidae: Scolytinae) play important roles in temperate conifer ecosystems, and also cause substantial economic losses. Although their general life histories are relatively similar, different species vary markedly in the physiological condition of the hosts they select. Most of ∼6000 known species colonise dead or stressed trees, a resource they share with a large diversity of insects and other organisms. A small number of bark beetle species kill healthy, live trees. These few are of particular interest as they compete directly with humans for resources. We propose that tree killing evolved when intense interspecific competition in the ephemeral, scarce resource of defence-impaired trees selected for genotypes that allowed them to escape this limitation by attacking relatively healthy trees. These transitions were uncommon, and we suggest they were facilitated by (a) genetically and phenotypically flexible host selection behaviours, (b) biochemical adaptations for detoxifying a wide range of defence compounds, and (c) associations with symbionts, which together aided bark beetles in overcoming formidable constitutive and induced host defences. The ability to detoxify terpenes influenced the evolutionary course of pheromonal communication. Specifically, a mate attraction system, which was exploited by intraspecific competitors in locating poorly defended hosts, became a system of cooperative attack in which emitters benefit from the contributions responders make in overcoming defence. This functional shift in communication was driven in part by linkage of beetle semiochemistry to host defence chemistry. Behavioural and phenological adaptations also improved the beetles’ abilities to detect when tree defences are impaired, and, where compatible with life history adaptations to other selective forces, for flight to coincide with seasonally predictable host stress agents. We propose a conceptual model, whereby the above mechanisms enable beetles to concentrate on those trees that offer an optimal trade-off between host defence and interspecific competition, along dynamic gradients of tree vigour and stand-level beetle density. We offer suggestions for future research on testing elements of this model.
47
Parker, Geoff A. "How Soon Hath Time… A History of Two “Seminal” Publications". Cells 10, n. 2 (1 febbraio 2021): 287. http://dx.doi.org/10.3390/cells10020287.
Testo completoAbstract (sommario):
This review documents the history of the two papers written half a century ago that relate to this special issue of Cells. The first, “Sperm competition and its evolutionary consequences in the insects” (Biological Reviews, 1970), stressed that sexual selection continues after ejaculation, resulting in many adaptations (e.g., postcopulatory guarding phases, copulatory plugs, seminal fluid components that modify female reproduction, and optimal ejaculation strategies), an aspect not considered by Darwin in his classic treatise of 1871. Sperm competition has subsequently been studied in many taxa, and post-copulatory sexual selection is now considered an important sequel to Darwinian pre-copulatory sexual selection. The second, “The origin and evolution of gamete dimorphism and the male-female phenomenon” (Journal of Theoretical Biology, 1972) showed how selection, based on gamete competition between individuals, can give rise to anisogamy in an isogamous broadcast spawning ancestor. This theory, which has subsequently been developed in various ways, is argued to form the most powerful explanation of why there are two sexes in most multicellular organisms. Together, the two papers have influenced our general understanding of the evolutionary differentiation of the two forms of gametic cells, and the divergence of sexual strategies between males and females under sexual selection.
48
Corkum, Lynda D. "PATTERNS IN MAYFLY (EPHEMEROPTERA) WING LENGTH: ADAPTATION TO DISPERSAL?" Canadian Entomologist 119, n. 9 (settembre 1987): 783–90. http://dx.doi.org/10.4039/ent119783-9.
Testo completoAbstract (sommario):
AbstractUsing regression analysis on data compiled from the literature, I compared relationships (forewing versus body length) of mayfly imagoes, as a measure of dispersal, between suborders (Schistonota and Pannota) and among habitat type (lotic, lentic, and mixed). There were no significant differences in slopes or intercepts of the regression lines between sexes. Forewing length changed less markedly with body size for species within the ancestral Schistonota than the Pannota. Regression lines for lake and river forms intersect at 7.85 mm (wing length) and 7.30 mm (body length). Small (body length < 7.3 mm) lentic mayflies have proportionately longer wings than small riverine forms. Large (body length > 7.3 mm) riverine mayflies have proportionately longer wings than lentic forms. Based on these relationships, small lake-dwelling mayflies and large riverine mayflies are best able to disperse. Mayfly species occurring in mixed (both rivers and lakes) habitats exhibited allometric relationships similar to mayflies restricted to rivers.
49
Julca, Irene, Marina Marcet-Houben, Fernando Cruz, Carlos Vargas-Chavez, John Spencer Johnston, Jèssica Gómez-Garrido, Leonor Frias et al. "Phylogenomics Identifies an Ancestral Burst of Gene Duplications Predating the Diversification of Aphidomorpha". Molecular Biology and Evolution 37, n. 3 (8 novembre 2019): 730–56. http://dx.doi.org/10.1093/molbev/msz261.
Testo completoAbstract (sommario):
Abstract Aphids (Aphidoidea) are a diverse group of hemipteran insects that feed on plant phloem sap. A common finding in studies of aphid genomes is the presence of a large number of duplicated genes. However, when these duplications occurred remains unclear, partly due to the high relatedness of sequenced species. To better understand the origin of aphid duplications we sequenced and assembled the genome of Cinara cedri, an early branching lineage (Lachninae) of the Aphididae family. We performed a phylogenomic comparison of this genome with 20 other sequenced genomes, including the available genomes of five other aphids, along with the transcriptomes of two species belonging to Adelgidae (a closely related clade to the aphids) and Coccoidea. We found that gene duplication has been pervasive throughout the evolution of aphids, including many parallel waves of recent, species-specific duplications. Most notably, we identified a consistent set of very ancestral duplications, originating from a large-scale gene duplication predating the diversification of Aphidomorpha (comprising aphids, phylloxerids, and adelgids). Genes duplicated in this ancestral wave are enriched in functions related to traits shared by Aphidomorpha, such as association with endosymbionts, and adaptation to plant defenses and phloem-sap-based diet. The ancestral nature of this duplication wave (106–227 Ma) and the lack of sufficiently conserved synteny make it difficult to conclude whether it originated from a whole-genome duplication event or, alternatively, from a burst of large-scale segmental duplications. Genome sequencing of other aphid species belonging to different Aphidomorpha and related lineages may clarify these findings.
50
Smith, M. A. H., I. L. Wise e R. J. Lamb. "Survival of Sitodiplosis mosellana (Diptera: Cecidomyiidae) on wheat (Poaceae) with antibiosis resistance: implication for the evolution of virulence". Canadian Entomologist 139, n. 1 (febbraio 2007): 133–40. http://dx.doi.org/10.4039/n06-027.
Testo completoAbstract (sommario):
AbstractSmall numbers of larval wheat midge, Sitodiplosis mosellana Géhin, survived and matured in each of five field seasons in a plot of spring wheat carrying the Sm1 gene for antibiosis resistance against this insect. Wheat midge developing on resistant wheat had higher survival in the laboratory than in the field, but survival was always very low compared with that of larvae developing on susceptible wheat. The mass of these larvae and their survival during diapause were approximately half those of larvae developing on susceptible wheat in both the laboratory and the field. The survival of some wheat midge larvae on resistant wheat, and their reduced mass, is consistent with the hypothesis that a virulence allele allowing adaptation to Sm1 is present in the population. Assuming this to be the case, the frequency of the allele in the population was estimated to be between 0.8 × 10−4 and 1.6 × 10−2, if surviving larvae are heterozygous for the allele. Although rare, a virulence allele occurring at this frequency would likely allow the wheat midge to overcome the resistance gene Sm1 once resistant wheat is grown over a wide area.