Academic literature on the topic 'Nocturnal insects'

Nocturnal arthropods form the prey base for many predators and are an integral part of complex food webs. However, there is limited understanding of the mechanisms influencing invertebrates at urban water bodies and the potential flow-on effects to their predators. This study aims to: (i) understand the importance of standing water bodies for nocturnal flying insect orders, including the landscape- and local-scale factors driving these patterns; and (ii) quantify the relationship between insects and insectivorous bats. We investigated nocturnal flying insects and insectivorous bats simultaneously at water bodies (n = 58) and non-water body sites (n = 35) using light traps and acoustic recorders in Melbourne, Australia. At the landscape scale, we found that the presence of water and high levels of surrounding greenness were important predictors for some insect orders. At the water body scale, low levels of sediment pollutants, increased riparian tree cover and water body size supported higher insect order richness and a greater abundance of Coleopterans and Trichopterans, respectively. Most bat species had a positive response to a high abundance of Lepidopterans, confirming the importance of this order in the diet of insectivorous bats. Fostering communities of nocturnal insects in urban environments can provide opportunities for enhancing the prey base of urban nocturnal insectivores.

We tested the hypothesis that the phototatic response of nocturnal insects is influenced by the flickering of light sources by comparing the numbers of insects captured in traps illuminated with flickering and non-flickering light. Four flicker profiles produced by a square pulse wave with different combinations of frequency and duty cycle were investigated. Overall, fewer insects were captured in traps illuminated with a flickering light source, independent of the flicker setting used. Furthermore, the difference observed was statistically significant for specific combinations of flickering conditions and insect orders, thus suggesting that flickering reduces the number of nocturnal insects attracted to light sources.

Despite their tiny eyes and brains, nocturnal insects have evolved a remarkable capacity to visually navigate at night. Whereas some use moonlight or the stars as celestial compass cues to maintain a straight-line course, others use visual landmarks to navigate to and from their nest. These impressive abilities rely on highly sensitive compound eyes and specialized visual processing strategies in the brain.

Most gymnosperms are wind-pollinated, but some are insect-pollinated, and in Ephedra (Gnetales), both wind pollination and insect pollination occur. Little is, however, known about mechanisms and evolution of pollination syndromes in gymnosperms. Based on four seasons of field studies, we show an unexpected correlation between pollination and the phases of the moon in one of our studied species, Ephedra foeminea . It is pollinated by dipterans and lepidopterans, most of them nocturnal, and its pollination coincides with the full moon of July. This may be adaptive in two ways. Many nocturnal insects navigate using the moon. Further, the spectacular reflection of the full-moonlight in the pollination drops is the only apparent means of nocturnal attraction of insects in these plants. In the sympatric but wind-pollinated Ephedra distachya , pollination is not correlated to the full moon but occurs at approximately the same dates every year. The lunar correlation has probably been lost in most species of Ephedra subsequent an evolutionary shift to wind pollination in the clade. When the services of insects are no longer needed for successful pollination, the adaptive value of correlating pollination with the full moon is lost, and conceivably also the trait.

Night vision is ultimately about extracting information from a noisy visual input. Several species of nocturnal insects exhibit complex visually guided behaviour in conditions where most animals are practically blind. The compound eyes of nocturnal insects produce strong responses to single photons and process them into meaningful neural signals, which are amplified by specialized neuroanatomical structures. While a lot is known about the light responses and the anatomical structures that promote pooling of responses to increase sensitivity, there is still a dearth of knowledge on the physiology of night vision. Retinal photoreceptors form the first bottleneck for the transfer of visual information. In this review, we cover the basics of what is known about physiological adaptations of insect photoreceptors for low-light vision. We will also discuss major enigmas of some of the functional properties of nocturnal photoreceptors, and describe recent advances in methodologies that may help to solve them and broaden the field of insect vision research to new model animals. This article is part of the themed issue ‘Vision in dim light’.

AbstractNocturnal vision in insects depends on the ability to reliably detect scarce photons. Nocturnal insects tend to have intrinsically more sensitive and larger rhabdomeres than diurnal species. However, large rhabdomeres have relatively high membrane capacitance (Cm), which can strongly low-pass filter the voltage bumps, widening and attenuating them. To investigate the evolution of photoreceptor signaling under near dark, we recorded elementary current and voltage responses from a number of species in six insect orders. We found that the gain of phototransduction increased with Cm, so that nocturnal species had relatively large and prolonged current bumps. Consequently, although the voltage bump amplitude correlated negatively with Cm, the strength of the total voltage signal increased. Importantly, the background voltage noise decreased strongly with increasing Cm, yielding a notable increase in signal-to-noise ratio for voltage bumps. A similar decrease in the background noise with increasing Cm was found in intracellular recordings in vivo. Morphological measurements of rhabdomeres were consistent with our Cm estimates. Our results indicate that the increased photoreceptor Cm in nocturnal insects is a major sensitivity-boosting and noise-suppressing adaptation. However, by requiring a compensatory increase in the gain of phototransduction, this adaptation comes at the expense of the signaling bandwidth.

The optical design of most insect apposition compound eyes should restrict activity to daylight because at night the tiny lenses of the isolated ommatidia cannot collect sufficient light. However, several bee species have adopted nocturnal activity, taking advantage of the benefits of night foraging. By measuring behavioural visual performance in honeybees, we show that insects can possess better spatial resolution in dim light than the optics and physiology of their apposition eyes suggest, implying the presence of higher neural mechanisms which enhance vision at night. Theoretical calculations reveal that honeybees improve light capture at night by neurally summing photons in space and time. Even though summation compromises both spatial and temporal resolution, the improved photon capture enhances vision sufficiently for bees to discriminate coarse images in moonlight. This explains how bees and many other insects can adopt a nocturnal life style despite having an eye design typical of a day-active insect.

Many bat species in Europe have undergone severe population declines during the last century and one of the driving causes is believed to be the loss of roosting and foraging habitat through agricultural expansion and intensification. Modern agricultural practices have also had strong negative effects on many insect groups, such as moths, which are important components of the diets of many bat species. Agri-environment schemes (AES) have been introduced in many countries as an attempt to counteract the negative effects of intensive agriculture on biodiversity by providing financial incentives for farmers to adopt environmentally-sensitive agricultural practices. AES are potentially beneficial to bats and nocturnal insects, but the response of these taxa to their implementation had not been assessed prior to this study. Here, the potential benefits (or otherwise) that bats and their insect prey species gain from the implementation of certain AES management prescriptions was assessed using ultrasonic detectors (to assess bat activity levels) and heath light traps (to quantify nocturnal insect abundance) at 18 pairs of AES and conventionally-managed farms. In addition, the influence of the surrounding landscape on bats and insects was quantified to evaluate the relevance of a landscape-scale management approach for the conservation of these taxa. Some of the AES prescriptions assessed in this study benefited moths (and are potentially beneficial for moth-eating bats), but not Pipistrelle bats nor their insect prey. The most important factors associated with bat activity on farmland were metrics related to woodland configuration in the surrounding landscape, which suggests that conservation efforts for bats should focus on the creation and management of this habitat. Currently, some AES prescriptions aim to increase the amount and quality of woodland on agricultural land, but little is known about how woodland character relates to bat abundance and insect prey availability; therefore, recommendations for woodland creation and management rarely consider the requirements of foraging bats. Here, the influence of woodland character (e.g. vegetation structure and patch configuration) on bats and nocturnal insects was assessed. Vegetation surveys were conducted and Geographic Information Systems (GIS) were used to quantify the vegetation character and spatial configuration of 34 woodland patches within farmland. Two complementary methods (acoustic monitoring and bat trapping assisted by an acoustic lure) were used to assess the influence of woodland vegetation character, patch configuration and the surrounding landscape on bat populations. Nocturnal insect abundance at each site was assessed using heath light traps. Data presented here demonstrate that bats show species-specific associations with woodland vegetation structure and patch configuration; patterns of higher bat abundance and activity at small and isolated woodland patches suggest that bats utilize this habitat more intensively in landscapes where woodland is scarce. This thesis also shows that moths are strongly influenced by woodland character; in general, large woodland patches of compact shapes, composed of a large number of native tree species and a dense understory cover, and located close to other woodlands were associated with high moth abundance and species richness (and are potentially valuable for moth-eating bats). Other nocturnal insects (mainly Diptera) were not influenced by woodland character. This study also shows that bats and nocturnal insects are influenced by the landscape context; moths are mainly influenced by the extent of semi-natural environment (such as rough grassland and scrub) within small spatial scales (within 250 m; although effects of woodland extent were detected at larger spatial scales for woodland specialists moths). Bats are mainly influenced by woodland-related landscape metrics. Some bat species are influenced by the surrounding landscape at large spatial scales (within 3 km) and would benefit from woodland creation and management at a wide-landscape-scale. The findings presented in this thesis have important management implications for the design of agri-environment schemes. A list of management recommendations to optimize the benefits that bats and nocturnal insects gain from these schemes is presented in the final section.

The foraging activity of day-active bees often rely on flower availability, light intensity and temperature. However, some bees developed a nocturnal habit and fly during the dusk, dawn and night. We still do not know how these bees cope with environmental factors, especially dimmer light levels, to explore flower earlier than their diurnal relatives. Given that typical bee apposition compound eyes work better in brighter environments and function in their limits in dim-light conditions, we can expect a larger dependence of light intensity for nocturnal groups. Nocturnal and crepuscular bees are frequent visitors of cambuci (Campomanesia phaea, Myrtaceae) in southeastern Brazil. We aimed to investigate how light intensity affects flower visitation of cambuci by nocturnal and crepuscular bees, also controlling for other environmental factors. We counted visits per minute along 30 nights/twilights in 33 cambuci trees from a commercial orchard, measuring the following environmental variables: light intensity, flower availability, temperature, air relative humidity and wind speed. Light intensity is the only variable that explained flower visitation of nocturnal bees in cambuci, which peaks at intermediate light levels that occur around 30 minutes before sunrise. The minimum light intensity threshold to bees start flying is of 0.00024 cd/m2, the first recorded value for nocturnal and crepuscular bees finding flowers in an agro-forest context. Our results highlight for the first time how nocturnal bees rely on light to explore resources and show that the bees light-dependent foraging activity is not always linear, as postulated by previous theoretic models. This is the first step to understand how nocturnal bees react to environmental factors. Our findings also bring concerns about possible negative effects of light pollution at night for cambuci-crepuscular bees interaction
O forrageio de abelhas geralmente depende de disponibilidade de flores, intensidade de luz e temperatura. Contudo, algumas abelhas desenvolveram hábitos noturnos e voam durante os crepúsculos e a noite. Não se sabe como essas abelhas lidam com os fatores ambientais, especialmente os reduzidos níveis de luminosidade. Dado que os olhos compostos de aposição de abelhas funcionam melhor em maiores luminosidades, espera-se uma maior dependência da luz para os grupos noturnos. Abelhas noturnas e crepusculares são visitantes frequentes do cambuci (Campomanesia phaea, Myrtaceae) no sudeste do Brasil. Nosso objetivo foi investigar como a intensidade de luz afeta a visitação floral do cambuci por abelhas noturnas e crepusculares, controlada também por outros fatores ambientais. Para isso, contamos as visitas a cada minuto ao longo de 30 noites/crepúsculos em 33 árvores de cambuci em um pomar comercial, medindo as seguintes variáveis ambientais: intensidade de luz, disponibilidade de flores, temperatura, umidade e velocidade do vento. A intensidade de luz foi a única variável que explicou a visitação floral de abelhas noturnas no cambuci, a qual tem um pico em níveis intermediários de luz que ocorrem ao redor de 30 minutos antes do nascer do sol. O limiar mínimo de intensidade de luz para as abelhas começarem a voar foi de 0.00024 cd/m2, o primeiro valor registrado para abelhas noturnas e crepusculares procurando por flores em um contexto agroflorestal. Nossos resultados destacam pela primeira vez como as abelhas noturnas dependem da luz para explorar recursos e mostram que essa dependência, para abelhas em geral, não é sempre linear, como postulado por modelos teóricos prévios. Este é o primeiro passo para entender como abelhas noturnas reagem a fatores ambientais. Nossos dados também trazem alertas para possíveis efeitos negativos da poluição luminosa à noite para a interação entre cambuci e abelhas noturnas

Abstract In dim light, reliable coding of visual information becomes compromised, unless the sensitivity of the visual system to light is improved by structural and functional adaptations. Thus far, many adaptations for night vision in the compound eyes of nocturnal insects have been described, but little is known about the mechanisms underlying the electrochemical signalling in their photoreceptors. In this thesis, whole-cell patch-clamp and mathematical modelling are utilised to study basic electrical properties and ionic currents in photoreceptors of two nocturnal insects, the American cockroach Periplaneta americana and the field cricket Gryllus bimaculatus. Photoreceptors in both species showed large input resistance, membrane capacitance and phototransduction gain (large single photon responses) compared with most studied diurnal insects, providing improved sensitivity to light. The photoreceptors also expressed two voltage-sensitive outward currents: a transient current and a sustained current. The cricket photoreceptor expressed a dominating transient current, which is a typical characteristic for insects adapted for slow vision in dim light. By contrast, in the majority of cockroach photoreceptors the sustained current dominated, which is more common among fast diurnal species. Model simulations indicated that the sustained current is necessary for improved photoreceptor dynamics. Examination of light-induced currents suggested that the functional variability in cockroach photoreceptors is in part derived from variations in the total area of the photosensitive membrane. Recordings of light-induced currents also revealed that the cockroach light-gated channels are only moderately Ca2+-selective and that the polarisation-sensitive photoreceptors of the cricket may utilise phototransduction machinery in some details different from that in regular photoreceptors. Furthermore, the dynamics and information transfer rates of polarisation-sensitive photoreceptors in the cricket were clearly inferior to their regular counterparts, suggesting that they are not necessary for image formation.

Memoria para optar al Título Profesional de: Ingeniero en Recursos Naturales Renovables
La deforestación y fragmentación de los bosques nativos son una amenaza a la biodiversidad, alterando la biota e interacciones ecológicas. En el bosque Maulino, la herbivoría sobre Aristotelia chilensis (maqui) es negativamente afectada por la fragmentación del bosque, siendo mayor en el bosque continuo que en los fragmentos, particularmente a inicios de la temporada de crecimiento. Este fenómeno puede deberse a cambios en la dinámica de las poblaciones de defoliadores, esencialmente insectos. En este trabajo se evaluó la abundancia, riqueza de especies y composición de insectos defoliadores de actividad nocturna presentes en A. chilensis en un bosque continuo (600 ha) y en ocho fragmentos remanentes (0,4- 20 ha). Los muestreos se realizaron mensualmente, entre agosto de 2005 y febrero de 2006, en 32 ejemplares adultos de A. chilensis en el bosque continuo y en 32 ejemplares en los fragmentos. Los insectos fueron muestreados durante las 5 primeras horas después del anochecer. En cada árbol, durante 10 min se observaron todas las hojas de 5 ramas, colectando los insectos presentes. Además, se utilizó el método de sacudido de follaje y paraguas entomológico. Se colectaron 890 insectos defoliadores, pertenecientes a 17 familias y 77 especies de Coleoptera, Orthoptera y Lepidoptera. El 93,5% de las especies fueron identificadas a nivel de especie o morfoespecie, siendo todas nativas. La abundancia total no varió según el hábitat. Sin embargo, a nivel de orden, familia o especie hubo un efecto de la fragmentación taxón-dependiente. La riqueza de especies por árbol tampoco fue afectada por la fragmentación del bosque, aunque el número total de especies fue considerablemente mayor en los fragmentos que en el bosque continuo. La similitud de especies fue mayor dentro del bosque continuo que entre el bosque continuo y los fragmentos o que entre los fragmentos. A principios de la temporada (Septiembre), la abundancia de Sericoides obesa, insecto muy voraz, fue significativamente mayor en el bosque continuo que en los fragmentos. Al avanzar en la temporada, Chrysomelidae y Sericoides viridis se hicieron más abundantes en los fragmentos. Estos insectos serían los principales responsables de los patrones de defoliación de A. chilensis en el bosque Maulino.
In this work, the effect of the Maulino forest fragmentation on the abundance, species richness and composition of nocturnal defoliating insects associated with A. chilensis was evaluated. The insects were sampled every month, between August 2005 and february 2006, in 32 A. chilensis trees located in a continuous forest (600 ha) and in 32 trees from eight forest fragments (0,4- 20 ha). Sampling was carried out during the first 5 hours after dusk. 890 defoliating insects from 17 families and 77 species of Coleoptera, Orthoptera and Lepidoptera were collected. All species were native. The total abundance did not vary with habitat fragmentation. Nevertheless, at the ordinal, family or species level there was a taxon-dependent habitat fragmentation effect. The species richness per tree did not vary with forest fragmentation, though the total number of species was considerably higher in the forest fragments. The species similarity was higher within the continuous forest than between the continuous forest and fragments or between the fragments. At the beginning of the season (September), the abundance of Sericoides obesa, a very voracious folivorous species, was significantly higher in the continuous forest than in the forest fragments. Later in the season, Chrysomelidae and Sericoides viridis became more abundant in the forest fragments. These insects seem to be responsible of the defoliating patterns of A. chilensis at the Maulino forest.

L'olfaction joue un rôle majeur dans la recherche de la plante hôte chez les papillons de nuit. La compréhension des mécanismes d'attraction d'un ravageur, l'Eudémis de la vigne, Lobesia botrana, par sa plante hôte est essentielle pour développer de nouvelles méthodes de lutte biologique. J'ai étudié le comportement olfactif ainsi que les bases neurophysiologiques et génétiques chez ce tortricide. Les expériences en tunnel de vol ont montré que seules les femelles accouplées répondent aux odeurs de plante. Les expériences d'électrophysiologie ont révélé que la structure et ka fonction des neurones dans le lobe antennaire (AL), étaient corrélées et varient suivant le sexe et l'état sexuel. Un atlas du AL en 3D a été construit et des glomérules ayant des arborisations dendritiques de neurones caractérisés physiologiquement ont été identifiés. J'ai identifié et cloné un gène, Lbfor (L. Botrana foraging). Son expression dans le cerveau étant plus élevée chez les femelles accouplées que chez les vierges, cela suggère un rôle dans la plasticité comportementale
Olfaction plays a major role in the process of host plant finding in moths. The understanding of the host plant attraction is essential to develop new biological control methods against a serious pest insect, the European grapevine moth, Lobesia botrana. I studied olfactory guided behaviour, as well as its neurological basis in this tortricid species. Wind tunnel experiments showed that only mated females responded to grapevine plant odours. Electrophysiological experiments revealed that structure and function of neurons in the primary olfactory centre, the antennal lobe (AL), were correlated and varied depending on sex and mating status. A complete 3D-AL atlas was reconstructed and glomeruli housing arborisations of physiologically characterised neurons were identified. I identified and cloned a gene, Lbfor (L. Botrana foraging). Its expression in the brain being is higher in mated than in virgin females, thus suggesting a role in behavioural plasticity

La gestion forestière durable nécessite d'évaluer l'impact des traitements et des pratiques sylvicoles sur la biodiversité. Dans les forêts domaniales françaises, les anciens taillis-sous-futaie de chêne sont convertis vers la futaie régulière dont la surface s'agrandit, et sont donc voués à disparaître dans les décennies à venir.

Dans ce contexte, nous avons étudié l'impact à court terme de deux types de coupes d'intensités différentes (la coupe d'ensemencement et la coupe d'éclaircie), ainsi que la succession et la reconstitution des communautés de macro-Lépidoptères nocturnes au cours de la première moitié du cycle de futaie régulière, en référence aux anciens taillis-sous-futaie. Une deuxième partie aborde le rôle des caractéristiques dendrométriques, structurales et floristiques du peuplement forestier. Les travaux, menés en forêt domaniale de Montargis (45), ont nécessité une mise au point de la méthode d'échantillonnage pour comparer de manière synchronique 6 stades sylvicoles (incluant celui d'avant conversion) répartis parmi 35 sites. Les analyses ont porté sur la communauté entière, sur des groupes écologiques et biologiques définis a priori (selon l'habitat, le type et le nombre de plantes-hôtes consommées, le stade hivernant et la capacité de dispersion) et sur les espèces suffisamment fréquentes. Les réponses sont perçues à travers les variations de richesse spécifique, d'abondance absolue et de composition en espèces.

La coupe d'ensemencement, de forte intensité et initiatrice du cycle sylvicole, entraîne rapidement une modification profonde des communautés et la chute de la richesse spécifique et de l'abondance totales. La coupe d'éclaircie, de faible intensité, ne modifie pas la richesse et l'abondance totales et très peu la composition spécifique. Au cours du cycle sylvicole, la composition spécifique évolue pour se rapprocher, en jeune futaie vers 110 ans, de la composition d'origine. La richesse et l'abondance totales augmentent dans les stades jeunes pour atteindre un maximum en bas-perchis vers 45 ans puis tendent à diminuer légèrement jusqu'en jeune futaie où leurs valeurs d'origine sont retrouvées. La majorité des espèces est indifférente à la coupe et au cycle mais les autres ont des réponses contrastées. Les réponses des groupes étudiés suivent celle de la communauté entière, y compris pour les espèces supposées favorisées par la coupe (espèces de milieux ouverts, espèces liées aux herbacées). Néanmoins des tendances permettent de classer les espèces en deux groupes. Les espèces les plus défavorisées par la coupe d'ensemencement à court et à long terme sont les forestières, celles liées aux ligneux, les monophages, celles hivernant au stade d'œuf et les Geometridae, moins aptes à la dispersion. Les espèces les moins défavorisées sont les eurytopes, celles liées aux herbacées, les polyphages, celles hivernant au stade de chenille et les Noctuidae, plus aptes à la dispersion. La surprenante similarité des réponses des groupes (sauf pour les espèces lichénophages) à la coupe d'ensemencement peut être expliquée par un renseignement des traits d'espèce peu fiable et, au stade de régénération, par une plus faible détectabilité, des conditions micro-climatiques défavorables, une mauvaise qualité du feuillage, une prédation et un parasitisme élevés. Nous pensons que l'envergure moyenne des individus ne reflète pas la capacité de dispersion mais pourrait être liée au volume de vol disponible.

Dans les peuplements âgés, la richesse des Lépidoptères est liée positivement à la richesse floristique du sous-bois, mais sur l'ensemble des stades sylvicoles la richesse totale augmente avec l'hétérogénéité structurale du peuplement forestier (nombre de strates, recouvrement de la strate arbustive). La composition spécifique est aussi particulièrement liée à la richesse floristique du sous-bois.

Dans les limites de l'étude, la conversion ne semble pas menacer la diversité des Lépidoptères nocturnes. Toutefois, si les tendances observées se confirmaient, la deuxième moitié du cycle de futaie régulière serait défavorable aux espèces forestières et à celles ayant une faible capacité de dispersion.

M.Sc.
The grassland biome of South Africa harbours rich ecosystem diversity. Some of the distinctive features of grassland biodiversity in South Africa include globally significant centres of plant endemism, half of the country's endemic mammal species, a third of its endangered butterfly species and 10 of 14 of its globally threatened bird species. Grassland is one of the most inadequately maintained biomes in Southern Africa because 23% is under cultivation, 60% is irreversibly transformed and most of the remaining natural area is used as rangeland for livestock. Only 2% of the grassland biome is currently protected. Grasslands provide essential ecosystem services for economic development, but this biome also supports a large human population whose resource demands have serious environmental implications that threaten the grasslands‘ biodiversity. Urbanisation is possibly one of the major immediate threats to the grassland ecology in South Africa. This is also the case in the Cradle of Humankind World Heritage Site (COHWHS) and adjacent areas. New housing complexes and informal housing are encroaching on the COHWHS. Indigenous fauna and flora are being affected by ecologically insensitive urban development. This poses a major threat to the fauna of this region including the insects that occur in grassland habitats. The insects play a vital role as pollinators in grassland habitats and form an essential food source to a range of predators, including grass owls, shrews, bull frogs, lizards and bats. In order to conserve the insects and therefore the food web of which they form part, it is necessary to understand the diversity of the insects in the grassland in the dolomitic areas. The COHWHS is a world renowned heritage site devoted to the origin of humankind and is characterised by dolomitic caves. These caves are also the home of a large population of bats consisting of several species. The negative impact on the grasslands in the COHWHS and surroundings pose a threat to the survival of these bat populations if the food source they depend on is negatively affected. For this reason it is important to determine which flying nocturnal insect species are available in the grasslands surrounding bat roosts in the COHWHS and surroundings. 3 The choice of location for the primary trap site was made on the basis of its proximity to known bat roosts and the fact that it is situated in a nature reserve that, although the river is polluted, contains an otherwise relatively unspoilt grassland habitat. Sampling took place over a period of 14 months during which fluctuations in the insect population was observed. The fluctuations can be ascribed to seasonal climate changes and the three veld fires that occurred during this period. This fluctuation was most evident in the representatives of the Orders Lepidoptera and Coleoptera sampled.

Tese de mestrado, Ecologia e Gestão Ambiental, Universidade de Lisboa, Faculdade de Ciências, 2019
Biodiversity is declining worldwide, and one of its main causes is the expansion and intensification of agriculture. This process has been studied mainly for vertebrates and a few invertebrate groups, but information is missing for most insects despite their deep relationship with agriculture. This is partly due to difficulties in species identification, which requires taxonomic expertise and is costly and time consuming, especially for highly diverse insect communities. In traditional species identification, external or internal morphological characters are used to distinguish between different biological entities, one specimen at a time. Moreover, for many insect species only adult males (or females) can be reliably identified, and identification of larval stages or specimens in poor condition is often not possible. Recently, the development of next generation sequencing (NGS) of DNA is revolutionizing the ability to study highly diverse biological communities, by providing a relatively simple and inexpensive method for species identification. However, this approach remains little used in biodiversity assessment and monitoring, particularly in the case of nocturnal insects. Here we develop and test a workflow based on DNA metabarcoding for understanding how agricultural land uses affect the diversity and composition of nocturnal insect communities. Samples were collected in a complex mosaic landscape in NE Portugal in July (70 sites) and September (78) 2017 using UV light traps, covering four habitats with decreasing level of human management and increasing vegetation cover: vineyards, olive groves, cork oak woodland and riparian zones. Each site yielded a bulk sample of insects, which was processed using standard molecular and bioinformatics pipelines to produce a list of taxa identified at the lowest possible taxonomic level. Molecular procedures involved the testing of four metabarcoding primers, one of which produced the best results and was used in subsequent metabarcoding amplification. Validation of the method involving 12 samples revealed a close matching, albeit not perfect, between the species of moth (Lepidoptera) visually identified by a taxonomist and those recovered through metabarcoding. Metabarcoding of the bulk samples retrieved 1130 taxa, most of which were Lepidoptera (429 OTUs), Diptera (244) and Coleoptera (166). Despite this large number of taxa, accumulation curves revealed that sampling effort was still insufficient to capture the entire diversity within each habitat. There was significant variation in richness among habitats and between seasons, with vineyards showing consistently the lowest number of taxa. In contrast, the richness of olive groves was comparable, or even higher than that of the more natural cork oak and riparian habitats. The assemblage composition varied markedly across seasons, while variation among habitats was less marked, though there were differences in both characteristic and exclusive species. Variation in moth assemblage composition among habitats and seasons was related to functional traits, with for instance larger species recorded in cork oak and riparian habitats and in September, species with specialized diets in cork oak and September, and detritivore species in September. Overall, this workflow provides an efficient tool to assess and monitor nocturnal insects, with the potential for greatly advancing our understanding of agricultural impacts on biodiversity.
A disrupção de sistemas naturais está associada à perda de biodiversidade e actualmente põe em risco o equílibro de toda a biosfera. Apesar do desenvolvimento e implementação de medidas de protecção de biodiversidade, muitas espécies continuam em perigo. Devido maioritariamente à acção humana as ameaças à diversidade natural são inúmeras, potenciando a perda de espécies ainda desconhecidas, uma vez que grande parte da diversidade biológica continua por descrever ou descobrir. Desta forma, evidencia-se a necessidade de conhecer e monitorizar esta diversidade às escalas local e global. Só é possível desenvolver ações de conservação adequadas e medir o sucesso das mesmas ao encontrar formas de conhecer e quantificar a diversidade e de a monitorizar ao longo do tempo e do espaço. Neste contexto, são os insectos e outros invertebrados que mais carecem de estudo, monitorização e acções de conservação. Com milhões de espécies desconhecidas que interagem em sistemas complexos, o estudo das comunidades de insectos torna-se desafiante. Ainda assim, os poucos estudos existentes indicam que, à semelhança do que ocorre com os vertebrados, muitas espécies de insectos estão em declínio. No entanto, sabe-se que os insectos desempenham um papel essencial nos ecossistemas, sendo responsáveis por diversos serviços e desserviços, nomeadamente em ecossistemas agroflorestais. Por um lado, participam em processos essenciais como a polinização e reciclagem de nutrientes, e por outro lado, constituem potenciais pragas capazes de causar graves danos à produtividade e economia agrícola. Neste contexto, estudar insectos é particularmente relevante e um dos desafios tem sido a identificação das espécies. Esta constitui uma das componentes inerentes a estudos de biologia e ecologia, bem como ao desenvolvimento de planos de monitorização eficientes. Tradicionalmente, a identificação de espécies de insetos tem sido feita com base em características morfológicas externas ou internas, um espécime de cada vez. Contudo, este processo depende do trabalho de taxonomistas especializados, tornando-se dispendioso em termos de custo e tempo. Mais ainda, a maioria das espécies sofre metamorfose completa e muitos organismos são virtualmente impossíveis de identificar nas fases larvares, o que dificulta o processo. Hoje em dia, existem novos métodos moleculares que cada vez mais permitem ultrapassar alguns destes problemas. Entre estes, salientam-se os métodos que surgiram com o desenvolvimento de sequenciadores de nova geração (NGS), nomeadamente um conjunto de técnicas designado DNA metabarcoding. O DNA metabarcoding faz uso de primers universais na amplificação de barcodes em massa, provenientes de espécimes contidos em várias amostras complexas. Estas amostras são posteriormente marcadas com curtas sequências distintas, o que permite juntar (pooling) e sequenciar múltiplas amostras e posteriormente recuperar a sua composição individual. O uso desta metodologia tem cada vez mais vindo a ser reconhecido como particularmente útil em amostras cujo estado não permite identificação, como água ou guano, ou em amostras complexas compostas por misturas de espécies. Contudo tem ainda muitas limitações associadas, entre as quais a falta de protocolos standardizados, a necessidade de desenhar primers universais, a morosidade dos processos dos quais dependem a construção de bibliotecas de barcodes e algumas limitações bioinformáticas. Ainda assim, o método tem potencial de produzir resultados com elevada resolução taxonómica, permitindo identificar múltiplas espécies de uma só vez, sem a dependência de taxonomistas experientes. Neste estudo utilizamos o DNA metabarcoding para estimar a diversidade de artrópodes terrestres num parque natural recentemente designado, o Parque Natural e Regional do Vale do Tua (PNRVT). O parque natural, está inserido numa paisagem fortemente fragmentada que resulta num complexo mosaico agroflorestal, típico do Mediterrâneo. No total, foram recolhidas 144 amostras de insectos no PNRVT em dois períodos distintos, Julho (n=68) e Setembro (n=76). A amostragem ocorreu numa área geográfica vasta, que se estende por todo o parque natural, em 2 habitats agrícolas e 2 habitats semi-naturais/naturais representativos da paisagem agroflorestal fragmentada que lhe é característica. Os tipos de habitat foram definidos por ordem crescente de cobertura vegetal e decrescente de intervenção humana: vinhas, olivais, sobreirais e galerias ripícolas. Nas amostragens utilizaram-se armadilhas de luz ultravioleta (UV), e o conteúdo de cada armadilha foi processado separadamente em laboratório até ao pooling das amostras para a sequenciação. Especial atenção foi dada aos lepidópteros que são um grupo de insectos altamente diverso e pouco estudado. Para colmatar a falta de informação centralizada sobre muitos aspectos da sua biologia foram compilados um conjunto de traits de espécies desta ordem recorrendo a várias fontes online. Nomeadamente, compilaram-se traits morfológicos, fisiológicos, comportamentais e de distribuição geográfica. Estes dados foram utilizados para completar as análises do ponto de vista ecológico. Desenvolveu-se e utilizou-se um protocolo dividido em 4 fases para analisar os dados obtidos através da sequenciação Miseq i) teste piloto, e da sequenciação Hiseq ii) validação do método, iii) design para a monitorização ecológica e iv) análise de traits. Inicialmente utilizaram-se apenas 3 amostras para um teste piloto que incluiu testar a eficácia de vários primers. Todas as amostras foram sequenciadas posteriormente com o primer que produziu melhores resultados, o BF2/BR2. Este par de primers permitiu produzir mais identificações ao nível da espécie e menos sequências únicas, com menos erros e reduzindo o tempo de análise. A validação do método i.e. comparação dos resultados obtidos com metabarcoding e identificação visual permitiu verificar que a maioria das espécies de lepidópteros foi detectada. A sequenciação das restantes amostras recolhidas foi levada a cabo na mesma corrida (Hiseq). Estas foram recolhidas segundo o desenho de um plano de monitorização que incluiu a montagem e recolha de um número considerável de amostras nos 4 habitats representativos da paisagem, fornecendo dados para várias análises de riqueza e composição de espécies. As restantes análises foram efectuada para todas as unidades taxonómicas operacionais (OTUs) com excepção da última, a análise de traits, que se focou apenas nos lepidópteros, dada a sua importância ecológica e também pela disponibilidade de informação. Apesar de terem sido recolhidas 144 amostras, o esforço de amostragem provou-se insuficiente para atingir um número de espécies representativo da riqueza actual. Ainda assim, e apesar de não ser possível obter informação relativa à abundância das espécies, o método permitiu obter resultados com bastante resolução taxonómica. Deste modo foi possível captar as diferenças na riqueza e composição de espécies entre épocas e habitats através de análises exploratórias e testes de significância estatística. Verificou-se que as vinhas tendem a apresentar os valores de riqueza média mais baixos, em conjunto com os sobreirais em Julho. Por outro lado, nos olivais ocorreram alguns dos valores mais elevados riqueza de OTUs, bem como nos sobreirais em Setembro. As maiores diferenças entre a riqueza global de insectos e de lepidópteros registaram-se nas galerias ripícolas, indicando que este habitat é muito rico em outros taxa de insectos. Pelo contrário, em zonas de sobreiral destacou-se uma elevada riqueza em lepidópteros, especialmente em Setembro. Ao nível da composição das comunidades, as diferenças captadas parecem estar maioritariamente relacionadas com a época de recolha das amostras como seria expectável, dado que a maioria das espécies de insectos só está em fase adulta e activa numa determinhada época do ano. Contudo as análises indicam que o habitat também tem influência na composição das comunidades. As galerias ripícolas foram o habitat mais distinto em Julho enquanto que em Setembro os sobreirais tinham uma composição mais única de OTUs. A maioria das análises aponta para maiores semelhanças na composição das comunidades presentes em olivais e vinhas, quer ao nível geral de composição das amostras quer por partilharem algumas espécies dominantes. Foi possível relacionar certos traits das espécies de lepidópteros com a sua ocorrência na paisagem e nas duas épocas de amostragem. Nomeadamente, registou-se a presença de espécies de maiores dimensões em sobreirais e galerias ripícolas, a ocorrência de espécies de menores dimensões, com menor número de gerações e tendencialmente polífagas no mês de Julho e de espécies detrítivoras em Setembro. Ainda é difícil explicar muitos destes padrões e perceber o seu significado ecológico uma vez que a biologia destas espécies é pouco conhecida. Simultaneamente, são muitas espécies para avaliar e conhecer, pelo que o seu estudo além de necessário e desafiante, abre as portas a uma série de questões científicas que permanecem por responder. Conclui-se que o DNA metabarcoding tem potencial para integrar estudos ecológicos e como ferramenta para monitorização rápida e eficaz, reproduzível no tempo e no espaco, para identificação de espécies em amostras complexas de insectos. Aqui demonstramos que esta ferramenta pode ser particularmente útil em contextos de comparação de habitats em vastas zonas fragmentadas num curto período temporal, mas que pode também ser extensível com resultados reproduzíveis e comparáveis ao longo do tempo. A elevada resolução taxonómica do método permitiu detectar diferenças entre riqueza e composição de espécies em cada habitat. Nomeadamente, o método permitiu identificar espécies dominantes, e até relaccionar a ocorrência de certas espécies com os seus traits morfológicos, fisiológicos e comportamentais. Além disso, a estrutura de análise em 4 fases pode ser utilizada noutros contextos com as devidas adaptações. Na verdade, as várias fases do processo incluem testes e validações e servem para auto-calibrar e adaptar o método, tornando a sua aplicação possível em diversos contextos e paisagens. Ainda assim, várias limitações inerentes método mantêm-se, quer anível laboratorial, quer bioinformático, e por isso é necessário continuar a investigar o seu uso e promover a sua implementação como uma prática corrente em estudos ecológicos.

For many organisms there is a fitness advantage to being warm. Many organisms use behavioural thermoregulation to maintain a high body temperature during the day, basking in the sun to warm up and retreating to the shade to avoid overheating. This option is not open to most aquatic organisms, or those living in soil or sediment. It is also generally not possible for small or nocturnal organisms. A small number of active predatory fish utilise a counter-current heat exchanger (rete mirabile) to retain metabolic heat and warm their muscles, brain or eyes. A few have modified optical muscles as heater organs, and a range of plants generate heat to aid dispersal of scent and attract pollinators. A wide range of larger insects use rapid but unsynchronised muscle contraction to elevate their body temperature prior to flight, or other activity. In hot climates organisms may need to dissipate heat to avoid overheating. The major behavioural mechanism is shade-seeking, or for small organisms stilting or climbing onto objects such as plants to move out of the hottest air net to the ground. Larger mammals may tolerate a limited degree of warming during the day, releasing this in the cool of the night. Evaporative cooling is very effective at losing heat, but because it loses valuable water it can only be used sparingly in arid areas.

Mammals: A Very Short Introduction explores the nature, evolutionary history, and modern diversity of mammals. From a little shrew-like, nocturnal, insect-eating ancestor living 200 million years ago (mya), mammals have evolved into a huge variety of different kinds of animals. This VSI explains how it is endothermy—‘warm-bloodedness’—enabling high levels of activity and the relatively large brain associated with complex, adaptable behaviour that epitomizes mammals. It describes their remarkable fossil record, revealing how and when the mammals gained their characteristics, and the tortuous course of their evolution. It reveals the adaptations mammals evolved to suit their varied modes of life, including those of mainly arboreal primates culminating in Homo sapiens.

The Eastern Barred Bandicoot is one of Australia's most threatened species. When their existence came under extreme threat from habitat loss, predators and human development, Eastern Barred Bandicoots found refuge in the most unlikely of places – a rubbish tip. This captivating true story details the plight these small, nocturnal marsupials faced, and the outstanding efforts that ensured their protection. Written by Rohan Cleave and illustrated by Coral Tulloch, Bouncing Back shows that even on the brink of extinction, there is hope for the survival of our most vulnerable species. Rohan Cleave and Coral Tulloch's first book, Phasmid: Saving the Lord Howe Island Stick Insect, won a Whitley Award for Children's Natural History Book and was an Honour Book in the Children's Book Council of Australia Book Awards (Eve Pownall Information Book category). Bouncing Back is perfect for primary aged readers.

This chapter covers health issues and how to manage them. It covers acne, asthma, autistic spectrum disorders, behavioural disorders, birth injuries, problems with the bone and joint, cerebral palsy, cancer in childhood, cleft lip and palate, congenital heart defects and other impairments, constipation and encopresis, cystic fibrosis, deafness, depressive behaviours, eczema, emotional problems, endocrine problems, epilepsy, genetic problems, and growth disorders. It also includes infections and the consequences of infectious diseases in childhood, insects, neural tube defects, nocturnal enuresis, overweight children and adolescents, sickle cell disorders, thalassaemia, sudden infant death syndrome, and vomiting.

This chapter details how the author saw nighthawks while bird-watching in Lake Perez in Stone Valley. Nighthawks and their relatives — whip-poor-wills, oilbirds, frogmouths, pauraques, and nightjars — are odd, secretive, mostly crepuscular or nocturnal birds. On the wing, a common nighthawk is acrobatic and incredibly sleek. In the hand, however, its wings seem too long, its body squat and strange. A nighthawk's tiny black beak hides an enormous mouth that resembles a bullfrog's when it opens. Because they eat and drink while flying, this oversized mouth is useful for trapping insects and skimming lake water. The ancient Greeks and Romans believed that these unusual birds used their huge mouths for another purpose: drinking milk from the teats of goats and sheep under the cover of night. According to the lore, a goat suckled by a nightjar met an unfortunate end — blindness and then death. Of course, the birds do not engage in this behavior, but the belief earned their family the name Caprimulgidae, or “goatsucker.”