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Journal articles on the topic 'Allopatrie'
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1
Charles Baker, Myron. "Response of Male Indigo and Lazuli Buntings and Their Hybrids To Song Playback in Allopatric and Sympatric Populations." Behaviour 119, no. 3-4 (1991): 225–42. http://dx.doi.org/10.1163/156853991x00454.
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AbstractThe hybridizing semispecies indigo and lazuli buntings (Passerina cyanea, P. amoena) were studied in song playback experiments in allopatric and sympatric populations. In allopatry, males of both species responded strongly to conspecific and weakly to heterospecific songs. In sympatry, indigo, lazuli and hybrid males reacted equally and strongly to both indigo and lazuli songs. Alteration of song structures, by presenting indigo syllables in lazuli temporal pattern and lazuli syllables in indigo temporal pattern, showed that the response of allopatric indigo and lazuli males was determined primarily by syllabic (phonological) cues in the test songs and not by the temporal pattern. The overall pattern of male response in sympatry and allopatry provides some understanding of the observed degree of reproductive isolation between these species.
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Naretto, Sergio, Cecilia S. Blengini, Gabriela Cardozo, and Margarita Chiaraviglio. "Pre- and Postcopulatory Traits ofSalvatorMale Lizards in Allopatry and Sympatry." Scientifica 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/8176267.
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The reproductive traits of males are under influence of sexual pressures before and after copulation. The strength of sexual selection varies across populations because they undergo varying competition for mating opportunities. Besides intraspecific pressures, individuals seem to be subjected to pressures driven by interspecific interactions in sympatry. Lizards may vary their reproductive strategies through varying sexual characters, body size, gonadal investment, and sperm traits. We evaluated the reproductive traits, involved in pre- and postcopulatory competition, in allopatric and sympatric populations ofSalvatorlizards. We observed a spatial gradient of male competition among populations, with the following order: allopatric zone ofS. rufescens; sympatric zone; and allopatric zone ofS. merianae. Accordingly, variation in secondary sexual character, the relative testis mass, and the length of sperm component was observed between allopatry and sympatry in each species, suggesting differences in the investment of reproductive traits. However, we found that these twoSalvatorspecies did not differ in secondary sexual characters in sympatry. Interestingly, the trade-off between testes and muscle varied differently from allopatry to sympatry between theseSalvatorspecies, suggesting that the influence of social context on reproductive traits investment would affect lizard species differently.
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Johannesson, Kerstin, Marina Panova, Petri Kemppainen, Carl André, Emilio Rolán-Alvarez, and Roger K. Butlin. "Repeated evolution of reproductive isolation in a marine snail: unveiling mechanisms of speciation." Philosophical Transactions of the Royal Society B: Biological Sciences 365, no. 1547 (June 12, 2010): 1735–47. http://dx.doi.org/10.1098/rstb.2009.0256.
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Distinct ecotypes of the snail Littorina saxatilis , each linked to a specific shore microhabitat, form a mosaic-like pattern with narrow hybrid zones in between, over which gene flow is 10–30% of within-ecotype gene flow. Multi-locus comparisons cluster populations by geographic affinity independent of ecotype, while loci under selection group populations by ecotype. The repeated occurrence of partially reproductively isolated ecotypes and the conflicting patterns in neutral and selected genes can either be explained by separation in allopatry followed by secondary overlap and extensive introgression that homogenizes neutral differences evolved under allopatry, or by repeated evolution in parapatry, or in sympatry, with the same ecotypes appearing in each local site. Data from Spain, the UK and Sweden give stronger support for a non-allopatric model of ecotype formation than for an allopatric model. Several different non-allopatric mechanisms can, however, explain the repeated evolution of the ecotypes: (i) parallel evolution by new mutations in different populations; (ii) evolution from standing genetic variation; and (iii) evolution in concert with rapid spread of new positive mutations among populations inhabiting similar environments. These models make different predictions that can be tested using comprehensive phylogenetic information combined with candidate loci sequencing.
4
Surget-Groba, Yann, Helena Johansson, and Roger S. Thorpe. "Synergy between Allopatry and Ecology in Population Differentiation and Speciation." International Journal of Ecology 2012 (2012): 1–10. http://dx.doi.org/10.1155/2012/273413.
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The general diversity pattern of the Caribbean anole radiation has been described in detail; however, the actual mechanisms at the origin of their diversification remain controversial. In particular, the role of ecological speciation, and the relative importance of divergence in allopatry and in parapatry, is debated. We describe the genetic structure of anole populations across lineage contact zones and ecotones to investigate the effect of allopatric divergence, natural selection, and the combination of both factors on population differentiation. Allopatric divergence had no significant impact on differentiation across the lineage boundary, while a clear bimodality in genetic and morphological characters was observed across an ecotone within a single lineage. Critically, the strongest differentiation was observed when allopatry and ecology act together, leading to a sharp reduction in gene flow between two lineages inhabiting different habitats. We suggest that, for Caribbean anoles to reach full speciation, a synergistic combination of several historical and ecological factors may be requisite.
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Pitteloud, Camille, Nils Arrigo, Tomasz Suchan, Alicia Mastretta-Yanes, Roger Vila, Vlad Dincă, Juan Hernández-Roldán, et al. "Climatic niche evolution is faster in sympatric than allopatric lineages of the butterfly genus Pyrgus." Proceedings of the Royal Society B: Biological Sciences 284, no. 1852 (April 12, 2017): 20170208. http://dx.doi.org/10.1098/rspb.2017.0208.
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Understanding how speciation relates to ecological divergence has long fascinated biologists. It is assumed that ecological divergence is essential to sympatric speciation, as a mechanism to avoid competition and eventually lead to reproductive isolation, while divergence in allopatry is not necessarily associated with niche differentiation. The impact of the spatial context of divergence on the evolutionary rates of abiotic dimensions of the ecological niche has rarely been explored for an entire clade. Here, we compare the magnitude of climatic niche shifts between sympatric versus allopatric divergence of lineages in butterflies. By combining next-generation sequencing, parametric biogeography and ecological niche analyses applied to a genus-wide phylogeny of Palaearctic Pyrgus butterflies, we compare evolutionary rates along eight climatic dimensions across sister lineages that diverged in large-scale sympatry versus allopatry. In order to examine the possible effects of the spatial scale at which sympatry is defined, we considered three sets of biogeographic assignments, ranging from narrow to broad definition. Our findings suggest higher rates of niche evolution along all climatic dimensions for sister lineages that diverge in sympatry, when using a narrow delineation of biogeographic areas. This result contrasts with significantly lower rates of climatic niche evolution found in cases of allopatric speciation, despite the biogeographic regions defined here being characterized by significantly different climates. Higher rates in allopatry are retrieved when biogeographic areas are too widely defined—in such a case allopatric events may be recorded as sympatric. Our results reveal the macro-evolutionary significance of abiotic niche differentiation involved in speciation processes within biogeographic regions, and illustrate the importance of the spatial scale chosen to define areas when applying parametric biogeographic analyses.
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Pfennig, Karin S., and Alyssa B. Stewart. "Asymmetric reproductive character displacement in male aggregation behaviour." Proceedings of the Royal Society B: Biological Sciences 278, no. 1716 (December 22, 2010): 2348–54. http://dx.doi.org/10.1098/rspb.2010.2196.
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Reproductive character displacement—the evolution of traits that minimize reproductive interactions between species—can promote striking divergence in male signals or female mate preferences between populations that do and do not occur with heterospecifics. However, reproductive character displacement can affect other aspects of mating behaviour. Indeed, avoidance of heterospecific interactions might contribute to spatial (or temporal) aggregation of conspecifics. We examined this possibility in two species of hybridizing spadefoot toad (genus Spea ). We found that in Spea bombifrons sympatric males were more likely than allopatric males to associate with calling males. Moreover, contrary to allopatric males, sympatric S. bombifrons males preferentially associated with conspecific male calls. By contrast, Spea multiplicata showed no differences between sympatry and allopatry in likelihood to associate with calling males. Further, sympatric and allopatric males did not differ in preference for conspecifics. However, allopatric S. multiplicata were more variable than sympatric males in their responses. Thus, in S. multiplicata , character displacement may have refined pre-existing aggregation behaviour. Our results suggest that heterospecific interactions can foster aggregative behaviour that might ultimately contribute to clustering of conspecifics. Such clustering can generate spatial or temporal segregation of reproductive activities among species and ultimately promote reproductive isolation.
7
Bourassa, M., L. Bernier, and R. C. Hamelin. "Genetic Diversity in Poplar Leaf Rust (Melampsora medusae f. sp. deltoidae) in the Zones of Host Sympatry and Allopatry." Phytopathology® 97, no. 5 (May 2007): 603–10. http://dx.doi.org/10.1094/phyto-97-5-0603.
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Poplar leaf rust caused by Melampsora medusae f. sp. deltoidae is a widespread disease in North America, where epidemics occur within zones of sympatry and allopatry of telial hosts (Populus spp.) and aecial hosts (Larix spp.). To test the hypothesis that epidemics originate in the zone of sympatry where the rust can complete its life cycle, populations in sympatry and allopatry were analyzed with single-strand conformational polymorphism for codominant detection of alleles directly from uredinia. More alleles were detected in rust populations in the zone of host sympatry than in allopatry. Almost all alleles found in the zone of allopatry were a subset of the allelic diversity present in the zone of host sympatry. Distance analyses clustered populations according to geographic origin, but not sampling year or type of stand (plantation or natural stands). Large differences in allelic and genotypic frequency were observed between years in allopatry but not in sympatry, suggesting new colonizations in allopatric populations. Our results point to a dynamic and complex pattern of inoculum dissemination in polar leaf rust. The hypothesis most consistent with our results is that populations in sympatry represent a source of inoculum for epidemics, with some annual recolonization in allopatry, possibly via intermediate population jumps.
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Näslund, Ingemar, Erik Degerman, and Fredrik Nordwall. "Brown trout (Salmo trutta) habitat use and life history in Swedish streams: possible effects of biotic interactions." Canadian Journal of Fisheries and Aquatic Sciences 55, no. 4 (April 1, 1998): 1034–42. http://dx.doi.org/10.1139/f97-313.
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To test if habitat use and life history of stream-dwelling brown trout (Salmo trutta) differed between allopatric and sympatric situations, we compared three streams with differing fish communities and used data from a large national database containing electrofishing results from Swedish streams. In the three-creek study, allopatric brown trout used all habitats and shifted from nursery areas in riffles to pool habitats, where adult growth and survival were higher. Mainly females shifted habitat and this was undertaken after age 1. Sympatric brown trout under intense pressure from other fish species remained in the riffles throughout their life cycle. Under moderate pressure from other species, larger brown trout used slow-flowing habitats. Early growth was more rapid in sympatry. Sympatric brown trout also had a lower adult to juvenile growth ratio and lower adult survival and matured earlier than allopatric brown trout. The data from the nationwide database showed that frequency of occurrence and abundance of brown trout were negatively associated with the number of coexisting fish species. It was also verified that the habitat shifts between riffles and pools were more common and possibly more beneficial in terms of growth and survival in allopatry. In addition the existence of differences in juvenile growth between allopatric and sympatric populations was verified.
9
Henderson, M. A., and T. G. Northcote. "Retinal Structure of Sympatric and Allopatric Populations of Cutthroat Trout (Salmo clarki clarki) and Dolly Varden Char (Salvelinus malma) in Relation to their Spatial Distribution." Canadian Journal of Fisheries and Aquatic Sciences 45, no. 7 (July 1, 1988): 1321–26. http://dx.doi.org/10.1139/f88-155.
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Retinal structures of cutthroat trout (Salmo clarki clarki) and Dolly Varden char (Salvelinus malma) were compared to determine if these features were consistent with the different light regimes in which the species live, depending on their sympatry or allopatry in lakes. Cone cell density in sympatric trout was over twice that of sympatric char and rod cell density was slightly less. The cross-sectional size of cone cells in sympatric trout was approximately 30% less than in sympatric char. The ratios of photoreceptor cells to ganglion cells in sympatric trout and char retinas were approximately 40:1 and 80:1, respectively. There were no differences between sympatric and allopatric trout with respect to these structural features. Estimates of cone cell density, cone size, and number of photoreceptor cells per ganglion cell for allopatric char were significantly different and intermediate between those for sympatric trout and char. All four populations had similar cone cell mosaics with four paired cones surrounding each single cone. Results are considered in relation to differences in vertical distribution and feeding of sympatric and allopatric populations in three study lakes.
10
Pfennig, Karin S., and Michael J. Ryan. "Reproductive character displacement generates reproductive isolation among conspecific populations: an artificial neural network study." Proceedings of the Royal Society B: Biological Sciences 273, no. 1592 (February 16, 2006): 1361–68. http://dx.doi.org/10.1098/rspb.2005.3446.
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When interactions with heterospecifics prevent females from identifying conspecific mates, natural selection can promote the evolution of mating behaviours that minimize such interactions. Consequently, mating behaviours may diverge among conspecific populations in sympatry and in allopatry with heterospecifics. This divergence in conspecific mating behaviours—reproductive character displacement—can initiate speciation if mating behaviours become so divergent as to generate reproductive isolation between sympatric and allopatric conspecifics. We tested these ideas by using artificial neural networks to simulate the evolution of conspecific mate recognition in populations sympatric and allopatric with different heterospecifics. We found that advertisement calls diverged among the different conspecific populations. Consequently, networks strongly preferred calls from their own population to those from foreign conspecific populations. Thus, reproductive character displacement may promote reproductive isolation and, ultimately, speciation among conspecific populations.
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Malikov, V. G., and F. N. Golenishchev. "The systemic concept of formation and the problem of species." Species and speciation. Analysis of new views and trends 313, Supplement 1 (July 25, 2009): 117–40. http://dx.doi.org/10.31610/trudyzin/2009.supl.1.117.
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This concept of formation is quite similar to epigenetic one. The biological integrity is considered as an all-round concordance between constituents of structure, functioning, reacting and development, while an organism is seen as a dynamic-steady system of integrative relations between genome and phenome based on mutual influence. Any transformation or emergent self-organization within a living system is connected with the maintenance of its steady state. The adaptive constituent of the system’s steady state concerns to its fitness, and the structural constituent – to its steady-state structure. The only difference between ontogenesis and formation is that the object of the first one is an organism, while the object of the second one is a reproducing totality of organisms, which is elementary in the frame of typology and historically conditioned within a definite space. A species is considered as typologically indivisible and historically unrepeatable variant of steady relations between genome and phenome, which canalize the diversity of their own systemically permitted transformations. The «epigenetic» constituent of divergence between species is determined by difference in relations between phenome and genome, not by change of the latter’s compound. The «products» of epigenetic speciation distinctly differ in morphology and ecology, having a lack of post-zygotic reproductive isolation. The reproductive isolation between them is caused by ecological and ethological barriers. The genetic constituent of divergence between species is incompatibility between nonconspecific genomes, which more often is revealed in a form of hybrids sterility. The prevailing of the genetic constituent of interspecific divergence is caused by allopatrie in uniform environmental conditions. In such case, the genomic divergence is accompanied by invariable relations between genome and phenome, that determines morphological and ecological uniformity of cryptic species. The divergence between panmictic species more often includes both of the constituents in different ratio. Due to its universality, the systemic approach to the problem of species is also appropriate to apomictic organisms.
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Hume, Jeremy M. B., and Thomas G. Northcote. "Initial Changes in Use of Space and Food by Experimentally Segregated Populations of Dolly Varden (Salvelinus malma) and Cutthroat Trout (Salmo clarki)." Canadian Journal of Fisheries and Aquatic Sciences 42, no. 1 (January 1, 1985): 101–9. http://dx.doi.org/10.1139/f85-013.
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Dolly Varden (Salvelinus malma) (N = 881) and cutthroat trout (Salmo clarki) (N = 1571) were captured from a native lacustrine sympatric stock and transferred to two nearby lakes, formerly fishless, to establish allopatric populations with genetic backgrounds similar to the donor stock. Nearshore (5- and 10-m depth contours) vertical distributions of segregated Dolly Varden and cutthroat trout, between spring and autumn of the first 18 mo after transfer, did not differ significantly from those in their sympatric lake. Dolly Varden were captured mainly near the bottom while cutthroat trout were more evenly distributed throughout the water column. Nevertheless, initially the allopatric Dolly Varden rapidly became highly planktivorous, virtually eliminating midwater populations of Chaoborus trivittatus and C. americanus (third and fourth instar larvae) within a year. They later ate mainly benthic organisms as in the sympatric lake. Although allopatric cutthroat trout had a similar effect on Chaoborus larvae in their lake, they also ate more large benthic prey than did those in sympatry with Dolly Varden in the donor lake. These results suggest that while there may be genetic control restricting broad vertical use of space by formerly sympatric Dolly Varden shortly after being placed in allopatry, such control is flexible enough that a highly benthofagous stock in sympatry quickly becomes planktivorous in the absence of cutthroat trout.
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Gkenas, Christos, Maria Filomena Magalhães, Julien Cucherousset, Rafael Leonardo Orjuela, and Filipe Ribeiro. "Dietary niche divergence between two invasive fish in Mediterranean streams." Knowledge & Management of Aquatic Ecosystems, no. 420 (2019): 24. http://dx.doi.org/10.1051/kmae/2019018.
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Clarifying the mechanisms associated with the coexistence of invasive species is important to understand the overall impact of multiple invasions on recipient communities. Here we examined whether divergence or convergence in dietary niche occurred when invasive Lepomis gibbosus and Australoheros facetus coexist in Iberian streams. We used stomach content analyses to determine dietary niche composition, width, and overlap in allopatric and sympatric counterparts in the Lower Guadiana throughout the dry-season. The variations in dietary niche between pumpkinseed and the cichlid were consistent with predictions derived from the niche divergence hypothesis. Although there were no changes in the use of plant material from allopatry to sympatry in either species, sympatric pumpkinseed and the cichlid displayed marked shifts in the use of animal prey and a decrease in niche width relative to allopatric counterparts. Moreover, sympatric pumpkinseed and cichlid showed similar niche width but differed significantly in plant and animal prey use. Taken together these results suggest that divergence in dietary niches may play a role in mediating coexistence of multiple invaders in Iberian streams.
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Larranaga, Nicolas, Magnus L. Wallerius, Haoyu Guo, Julien Cucherousset, and Jörgen I. Johnsson. "Invasive brook trout disrupt the diel activity and aggregation patterns of native brown trout." Canadian Journal of Fisheries and Aquatic Sciences 76, no. 7 (July 2019): 1052–59. http://dx.doi.org/10.1139/cjfas-2018-0110.
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In European streams, native brown trout (Salmo trutta) feed primarily on aquatic prey but consume a higher proportion of terrestrial prey in sympatry with non-native brook trout (Salvelinus fontinalis). This is a rare example of diet convergence that may be associated with changes in diel activity or aggregation pattern by brown trout in sympatry. We recorded the activity and positions of brown trout from two origins and in two competition modes (allopatry versus sympatry, four combinations) placed in replicated stream enclosures for 29 days to test these hypotheses. Brown trout originating from or placed in sympatry were more diurnal and aggregated than those originating from or placed in allopatry. Changes in the diel activity of brown trout placed in a novel competition mode occurred progressively throughout the study. Thus, brown trout show strong behavioral flexibility in response to the non-native competitor and can revert to allopatric behavior when brook trout is removed from the system. These behavioral adjustments may have unsuspected effects on food webs and ecosystem functioning, which deserve further attention.
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Price, Trevor D. "The roles of time and ecology in the continental radiation of the Old World leaf warblers ( Phylloscopus and Seicercus )." Philosophical Transactions of the Royal Society B: Biological Sciences 365, no. 1547 (June 12, 2010): 1749–62. http://dx.doi.org/10.1098/rstb.2009.0269.
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Many continental sister species are allopatric or parapatric, ecologically similar and long separated, of the order of millions of years. Sympatric, ecologically differentiated, species, are often even older. This raises the question of whether build-up of sympatric diversity generally follows a slow process of divergence in allopatry, initially without much ecological change. I review patterns of speciation among birds belonging to the continental Eurasian Old World leaf warblers ( Phylloscopus and Seicercus ). I consider speciation to be a three-stage process (range expansions, barriers to gene flow, reproductive isolation) and ask how ecological factors at each stage have contributed to speciation, both among allopatric/parapatric sister species and among those lineages that eventually led to currently sympatric species. I suggest that time is probably the critical factor that leads to reproductive isolation between sympatric species and that a strong connection between ecological divergence and reproductive isolation remains to be established. Besides reproductive isolation, ecological factors can affect range expansions (e.g. habitat tracking) and the formation of barriers (e.g. treeless areas are effective barriers for warblers). Ecological factors may often limit speciation on continents because range expansions are difficult in ‘ecologically full’ environments.
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Rice, Amber M., Aaron R. Leichty, and David W. Pfennig. "Parallel evolution and ecological selection: replicated character displacement in spadefoot toads." Proceedings of the Royal Society B: Biological Sciences 276, no. 1676 (September 2, 2009): 4189–96. http://dx.doi.org/10.1098/rspb.2009.1337.
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Ecological character displacement—trait evolution stemming from selection to lessen resource competition between species—is most often inferred from a pattern in which species differ in resource-use traits in sympatry but not in allopatry, and in which sympatric populations within each species differ from conspecific allopatric populations. Yet, without information on population history, the presence of a divergent phenotype in multiple sympatric populations does not necessarily imply that there has been repeated evolution of character displacement. Instead, such a pattern may arise if there has been character displacement in a single ancestral population, followed by gene flow carrying the divergent phenotype into multiple, derived, sympatric populations. Here, we evaluate the likelihood of such historical events versus ongoing ecological selection in generating divergence in trophic morphology between multiple populations of spadefoot toad ( Spea multiplicata ) tadpoles that are in sympatry with a heterospecific and those that are in allopatry. We present both phylogenetic and population genetic evidence indicating that the same divergent trait, which minimizes resource competition with the heterospecific, has arisen independently in multiple sympatric populations. These data, therefore, provide strong indirect support for competition's role in divergent trait evolution.
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Dincă, Vlad, Kyung Min Lee, Roger Vila, and Marko Mutanen. "The conundrum of species delimitation: a genomic perspective on a mitogenetically super-variable butterfly." Proceedings of the Royal Society B: Biological Sciences 286, no. 1911 (September 18, 2019): 20191311. http://dx.doi.org/10.1098/rspb.2019.1311.
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The Palaearctic butterfly Melitaea didyma stands out as one of the most striking cases of intraspecific genetic differentiation detected in Lepidoptera: 11 partially sympatric mitochondrial lineages have been reported, displaying levels of divergence of up to 7.4%. To better understand the evolutionary processes underlying the diversity observed in mtDNA, we compared mtDNA and genome-wide SNP data using double-digest restriction site-associated DNA sequencing (ddRADseq) results from 93 specimens of M. didyma ranging from Morocco to eastern Kazakhstan. We found that, between ddRADseq and mtDNA results, there is a match only in populations that probably remained allopatric for long periods of time. Other mtDNA lineages may have resulted from introgression events and were probably affected by Wolbachia infection. The five main ddRADseq clades supported by STRUCTURE were parapatric or allopatric and showed high pairwise F ST values, but some were also estimated to display various levels of gene flow. Melitaea didyma represents one of the first cases of deep mtDNA splits among European butterflies assessed by a genome-wide DNA analysis and reveals that the interpretation of patterns remains challenging even when a high amount of genomic data is available. These findings actualize the ongoing debate of species delimitation in allopatry, an issue probably of relevance to a significant proportion of global biodiversity.
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Moran, Rachel L., and Rebecca C. Fuller. "Agonistic character displacement of genetically based male colour patterns across darters." Proceedings of the Royal Society B: Biological Sciences 285, no. 1884 (August 2018): 20181248. http://dx.doi.org/10.1098/rspb.2018.1248.
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Agonistic character displacement (ACD) occurs when selection to avoid maladaptive interspecific aggression leads to the evolution of agonistic signals and/or associated behavioural biases in sympatry. Here, we test for a pattern consistent with ACD in male colour pattern in darters (Percidae: Etheostoma ). Male colour pattern has been shown to function in male–male competition rather than female mating preferences in several darter species. Additionally, males bias their aggression towards conspecific over heterospecific males in sympatry but not in allopatry, consistent with divergent ACD in male behavioural biases. We use a common garden approach to show that differences in male colour pattern among four closely related darter species are genetically based. Additionally, we demonstrate that some aspects of male colour pattern exhibit enhanced differences in sympatric compared to allopatric populations of two darter species, consistent with ACD. However, other male colour traits are more similar between species in sympatry compared with allopatry, indicating that not all signal components are under strong divergent selection in sympatry. This study provides evidence that interspecific male–male aggressive interactions alone can promote elaborate male signal evolution both between and within species. We discuss the implications this has for male-driven ACD and cascade ACD.
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Christmas, Matthew J., Julia C. Jones, Anna Olsson, Ola Wallerman, Ignas Bunikis, Marcin Kierczak, Valentina Peona, et al. "Genetic Barriers to Historical Gene Flow between Cryptic Species of Alpine Bumblebees Revealed by Comparative Population Genomics." Molecular Biology and Evolution 38, no. 8 (April 6, 2021): 3126–43. http://dx.doi.org/10.1093/molbev/msab086.
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Abstract Evidence is accumulating that gene flow commonly occurs between recently diverged species, despite the existence of barriers to gene flow in their genomes. However, we still know little about what regions of the genome become barriers to gene flow and how such barriers form. Here, we compare genetic differentiation across the genomes of bumblebee species living in sympatry and allopatry to reveal the potential impact of gene flow during species divergence and uncover genetic barrier loci. We first compared the genomes of the alpine bumblebee Bombus sylvicola and a previously unidentified sister species living in sympatry in the Rocky Mountains, revealing prominent islands of elevated genetic divergence in the genome that colocalize with centromeres and regions of low recombination. This same pattern is observed between the genomes of another pair of closely related species living in allopatry (B. bifarius and B. vancouverensis). Strikingly however, the genomic islands exhibit significantly elevated absolute divergence (dXY) in the sympatric, but not the allopatric, comparison indicating that they contain loci that have acted as barriers to historical gene flow in sympatry. Our results suggest that intrinsic barriers to gene flow between species may often accumulate in regions of low recombination and near centromeres through processes such as genetic hitchhiking, and that divergence in these regions is accentuated in the presence of gene flow.
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Lukhtanov, Vladimir A., and Elena A. Pazhenkova. "The Taxa of the Hyponephele lycaon – H. lupina Species Complex (Lepidoptera, Nymphalidae, Satyrinae): Deep DNA Barcode Divergence despite Morphological Similarity." Folia Biologica 69, no. 1 (March 31, 2021): 11–21. http://dx.doi.org/10.3409/fb_69-1.02.
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The genus Hyponephele includes about 40 species distributed throughout the southern part of the Palaearctic area. Within this genus, the taxa of the H. lycaon – H. lupina species complex are similar with respect to the wing pattern and genitalia structure. Here we revise this group using analysis of butterfly morphology, DNA barcodes, and study of the type material. We show that, with a few exceptions, the species in this group are allopatric in distribution. Allopatry in combination with phenotypic similarity may be theoretically interpreted as evidence for the conspecifity of these taxa. Here we falsify this hypothesis by using DNA barcode analysis. We show that the species of this complex are genetically very distant and cannot be combined together as a polytypic species. We also demonstrate that H. lupina consists of two deeply diverged allopatric clades, H. lupina s. s. and H. mauritanica comb. & stat. nov. The barcode p-distance between these taxa (3.4-4.9%) is significantly higher than the generally accepted 'standard' minimum interspecific divergence (2.0-3.0% ) threshold. These two clades can also be distinguished by the color of the upperside of the wing in males (brown with conspicuous golden reflection in H. lupina ; dark brown without golden reflection in H. mauritanica) and by details in male genitalia and male androconia structures. Syntypes of Hyponephele sifanica, H. cheena cheena, H. cheena iskander, and H. cheena kashmirica are studied and figured.
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Rothfels, Klaus. "Speciation in black flies." Genome 32, no. 4 (August 1, 1989): 500–509. http://dx.doi.org/10.1139/g89-475.
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In many Simuliidae, patterns of spatial and temporal relationships among the most closely related species are more readily interpreted in terms of sympatric speciation than of allopatric speciation. Specific examples are (i) the allotriploid taxa in Gymnopais and other genera, (ii) the black fly faunas of geologically recent islands (Tahiti), and (iii) species in Prosimulium onychodactylum, a prototype of a continental multisibling species complex. A model of sympatric speciation is presented based on coadaptation of polymorphic sex chromosomes in pairs reinforced by progressive development of assortative mating. This model predicts that (i) populations should frequently exhibit sex-chromosome polymorphism, (ii) these sex-chromosome polymorphisms, and autosomal ones, should in some cases display linkage or association disequilibria, (iii) species pairs or complexes should be incurred that differ only in sex chromosomes and that share extensive ancestral autosomal polymorphisms, and (iv) such species should differ in their biology and perhaps their present-day distribution. Recent publications and observations are in accordance, in general, with predictions from the model. Genetic control, e.g., of diapause, larval developmental timing, and niche preference or ethology, could substitute as a basis of incipient cleavage. The evidence for sympatric speciation is purely inferential, but this is equally true for the allopatric interpretation, and in black flies the circumstantial evidence for prevalence of sympatric speciation appears more compelling. This is not to deny the efficacy of allopatry and founder effect in the origin of some species complexes.Key words: sympatric speciation, black fly, evolution.
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Wang, Y., H. Yu, K. Raphael, and A. S. Gilchrist. "Genetic delineation of sibling species of the pest fruit fly Bactocera (Diptera: Tephritidae) using microsatellites." Bulletin of Entomological Research 93, no. 4 (July 2003): 351–60. http://dx.doi.org/10.1079/ber2003249.
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AbstractUsing a large set of microsatellites, the genetic relationships between three closely related Australian fruit fly species, Bactrocera tryoni (Froggatt), B. neohumeralis (Hardy) and B. aquilonis(May) were investigated. Bactrocera tryoni and B. neohumeralis are sympatric, while B. aquilonis is allopatric to both. The sympatric species, B. tryoni and B. neohumeralis, were found to be genetically distinct. It is likely that despite differences in mating time between these two species, some gene flow still occurs. In contrast, the sibling species B. tryoni and B. aquilonis were found to be closely related, despite allopatry. The level of genetic divergence was similar to that found within eastern Australian populations of B. tryoni. Consideration of all available genetic data suggests that this similarity is not due to recent (i.e. within the last 30 years) displacement of B. aquilonis by B. tryoni from the B. aquilonis region (north-western Australia). Instead the data suggests that, at least in the areas sampled, asymmetrical hybridization may have occurred over a longer timescale.
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Dorcsi, M. "Allopathie und Homöopathie." Zeitschrift für Klassische Homöopathie 20, no. 02 (April 2, 2007): 65–69. http://dx.doi.org/10.1055/s-2006-937707.
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Leary, Christopher J. "Investigating opposing patterns of character displacement in release and advertisement vocalizations of Bufo fowleri and Bufo americanus (Anura; Bufonidae)." Canadian Journal of Zoology 79, no. 9 (September 1, 2001): 1577–85. http://dx.doi.org/10.1139/z01-115.
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Anuran release vocalizations function to prevent prolonged amplexus between males, whereas advertisement vocalizations potentially act as a premating isolation mechanism. To facilitate rapid release during heterospecific amplexus, selection should favor convergent character displacement in release vocalizations. Conversely, to promote isolation between sympatric congeners, selection should favor divergent character displacement in advertisement vocalizations. I examined properties of release and advertisement vocalizations of Bufo fowleri and Bufo americanus that are important in mate recognition (periodicity and dominant frequency) to determine if the two calls exhibit opposing patterns of character displacement. Release vocalizations showed no pattern of displacement. The periodicity of sympatric advertisement vocalizations differed from that of allopatric vocalizations for B. americanus but not for B. fowleri. However, the results were not consistent with the pattern expected for divergent character displacement because the two species differed in this parameter in allopatry. These results are compared with published reports of char acter displacement in the B. americanus species-group in the context of a possible mosaic hybrid zone for these species.
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Gray, D. A., P. Barnfield, M. Seifried, and M. H. Richards. "Molecular divergence between Gryllus rubens and Gryllus texensis, sister species of field crickets (Orthoptera: Gryllidae)." Canadian Entomologist 138, no. 3 (June 2006): 305–13. http://dx.doi.org/10.4039/n05-037.
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AbstractWe assess the degree of sequence divergence in the maternally inherited mitochondrial cytochrome c oxidase I (COI) and cytochrome b (CytB) genes between two sister species of field crickets, Gryllus rubens Scudder, 1902 and Gryllus texensis Cade and Otte, 2000. We analyzed 1460 base pairs from 10 individuals of each species; individuals were sampled from areas of both allopatry and sympatry. Overall average pairwise mitochondrial sequence divergence between species was 1.4% ± 0.1% (mean ± SD); however, there was almost an order of magnitude more divergence in COI (2.59% ± 2.25%) than in CytB (0.35% ± 0.24%). Gryllus texensis appears to harbor a much greater level of genetic variation than does G. rubens. Phylogenetic trees constructed from these sequences show reasonable separation of species; however, sequences are not reciprocally monophyletic. Gene tree polyphyly may reflect recent species-level divergence and (or) interspecific gene flow. The pattern of sequence divergence and genetic variation in these taxa is consistent with allopatric or peripatric speciation in Pleistocene glacial refugia in the southeastern (G. rubens ancestral lineage) and southcentral United States (G. texensis ancestral lineage).
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Hasegawa, Koh, and Koji Maekawa. "Potential of habitat complexity for mitigating interference competition between native and non-native salmonid species." Canadian Journal of Zoology 86, no. 5 (May 2008): 386–93. http://dx.doi.org/10.1139/z08-015.
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This study aimed to confirm the mitigation effect of structurally complex habitat on interspecific interference competition between native and non-native salmonid species. We evaluated the effects of habitat complexity (number and size of aggregates of large woody debris and length of undercut banks) and other habitat components that were related to the local abundance of salmonids (dimension and mean depth of pool, mean particle size, and mean current velocity) on the local abundance of native white-spotted char ( Salvelinus leucomaenis (Pallas, 1814)) in allopatry and sympatry with non-native brown trout ( Salmo trutta L., 1758). The field survey was conducted in a Japanese montane stream. The number of char in pool habitats in the allopatric area correlated positively with habitat size, i.e., pool dimension. The number of char in the sympatric area with trout was positively correlated with habitat complexity, while it was negatively correlated with number of trout. In this study, we found that structurally complex habitats might be effective in mitigating interspecific competition between native white-spotted char and non-native brown trout in a montane stream.
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Huang, Yan, Xiaoyi Wang, Xin Yang, Jianping Jiang, and Junhua Hu. "Unveiling the roles of interspecific competition and local adaptation in phenotypic differentiation of parapatric frogs." Current Zoology 66, no. 4 (January 24, 2020): 383–92. http://dx.doi.org/10.1093/cz/zoaa001.
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Abstract Understanding how ecological processes affect phenotypic evolution has been and continues to be an important goal of ecology and evolutionary biology. Interspecific competition for resources can be a selective force driving phenotypic differentiation that reduces competition among sympatric species (character divergence), enabling closely-related species to coexist. However, although patterns of character divergence are well documented in both empirical and theoretical researches, how local adaptation to abiotic environment affects trait evolution in the face of interspecific competition is less known. Here, we investigate how patterns in morphological traits of 2 parapatric frog species, Feirana quadranus and F. taihangnica, vary among allopatric and sympatric regions using range-wide data derived from extensive field surveys. Feirana quadranus was overall larger than F. taihangnica in body size (i.e., snout–vent length [SVL]), and the difference between SVL of both species in sympatry was larger than that in allopatry. From allopatry to sympatry, the 2 species diverged in foot and hand traits, but converged in eye size and interorbital span, even when we controlled for the effects of geographic gradients. Sympatric divergence in SVL, hand and foot traits is likely acting as a case of evolutionary shift caused by interspecific competition. In contrast, sympatric convergence of eye-related traits may derive at least partly from adaptation to local environments. These results imply the relative roles of interspecific competition and local adaptation in shaping phenotypic diversification. Our findings illustrate how traits evolve in parapatric species pair due to sympatric divergent and convergent evolution. It thus provides insights into understanding underlying evolutionary processes of parapatric species, that is, competition and local adaptation.
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Pigot, Alex L., and Joseph A. Tobias. "Dispersal and the transition to sympatry in vertebrates." Proceedings of the Royal Society B: Biological Sciences 282, no. 1799 (January 22, 2015): 20141929. http://dx.doi.org/10.1098/rspb.2014.1929.
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Under allopatric speciation models, a key step in the build-up of species richness is population dispersal leading to the co-occurrence of previously geographically isolated forms. Despite its central importance for community assembly, the extent to which the transition from spatial segregation (allopatry or parapatry) to coexistence (sympatry) is a predictable process, or alternatively one governed by chance and the vagaries of biogeographic history, remains poorly understood. Here, we use estimated divergence times and current patterns of geographical range overlap among sister species to explore the evolution of sympatry in vertebrates. We show that rates of transition to sympatry vary predictably according to ecology, being faster in marine or strongly dispersive terrestrial clades. This association with organism vagility is robust to the relative frequency of geographical speciation modes and consistent across taxonomic scales and metrics of dispersal ability. These findings reject neutral models of dispersal assembly based simply on evolutionary age and are not predicted by the main alternative view that range overlap is primarily constrained by biotic interactions. We conclude that species differences in dispersal limitation are fundamental in organizing the assembly of ecological communities and shaping broad-scale patterns of biodiversity over space and time.
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McHugh, Peter, and Phaedra Budy. "An experimental evaluation of competitive and thermal effects on brown trout (Salmo trutta) and Bonneville cutthroat trout (Oncorhynchus clarkii utah) performance along an altitudinal gradient." Canadian Journal of Fisheries and Aquatic Sciences 62, no. 12 (December 1, 2005): 2784–95. http://dx.doi.org/10.1139/f05-184.
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Temperature-mediated competition (i.e., dominance shifts between species depending on temperature) may explain the segregation of salmonid species along altitudinal stream gradients. We evaluated this hypothesis for exotic brown trout (Salmo trutta) and native Bonneville cutthroat trout (Oncorhynchus clarkii utah) by rearing them in experimental sympatry and allopatry using enclosures constructed at six sites spaced along a 45-km segment of a mountain stream. For both species, we compared condition and growth between allopatric and sympatric treatment groups. We found that brown trout negatively affected cutthroat trout performance, whereas cutthroat trout failed to impart an effect in the reverse direction, regardless of temperature. Thus, we documented asymmetric competition between these species but found little evidence indicating that its outcome was influenced by temperature. Brown trout cutthroat trout segregation is therefore unlikely to be due to temperature-mediated competition. Instead, brown trout may have displaced cutthroat trout from downstream areas through competition or other mechanisms, while abiotic factors preclude their (brown trout) invasion of upper elevations. Given the magnitude of effect observed in our study, we recommend that brown trout receive greater consideration in cutthroat trout conservation.
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Strümpher, Werner P., Catherine L. Sole, Martin H. Villet, and Clarke H. Scholtz. "Allopatric speciation in the flightless Phoberus capensis (Coleoptera: Trogidae) group, with description of two new species." Insect Systematics & Evolution 47, no. 2 (May 11, 2016): 149–79. http://dx.doi.org/10.1163/1876312x-47022138.
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The namePhoberus capensis(Scholtz) is applied to a small flightless, keratinophagous beetle endemic to the Cape Floristic Region of South Africa. Its gross distribution stretches from roughly 1000 km from the Cederberg (32°24’22” S, 19°04’50” E) to Grahamstown (33°20’07” S, 26°32’50” E). The populations are spatially discrete, restricted to relict forests of the southern Cape and disjunct high montane refugia of the Cape Fold Mountains. We test the hypothesis that there is more than one distinct species nested within the nameP.capensis. Phylogenetic relationships among populations were inferred using molecular sequence data. The results support three distinct evolutionary lineages, which were also supported by morphological characters. Divergence time estimates suggest Pliocene-Pleistocene diversification. Based on these results, it is suggested that theP.capensislineage experienced climatically-driven allopatric speciation with sheltered Afrotemperate forests and high mountain peaks serving as important refugia in response to climatic ameliorations. TheP. capensiscomplex thus represents a speciation process in which flight-restricted populations evolved in close allopatry, possibly as recently as the Pleistocene. Two divergent and geographically distinct lineages are described as novel species: The new species,P.disjunctussp. n. andP.herminaesp. n., are illustrated by photographs of habitus and male aedeagi.
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Ahmed-Braimah, Yasir H., and Bryant F. McAllister. "Rapid Evolution of Assortative Fertilization between Recently Allopatric Species of Drosophila." International Journal of Evolutionary Biology 2012 (January 18, 2012): 1–9. http://dx.doi.org/10.1155/2012/285468.
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The virilis group of Drosophila represents a relatively unexplored but potentially useful model to investigate the genetics of speciation. Good resolution of phylogenetic relationships and the ability to obtain fertile hybrid offspring make the group especially promising for analysis of genetic changes underlying reproductive isolation separate from hybrid sterility and inviability. Phylogenetic analyses reveal a close relationship between the sister species, Drosophila americana and D. novamexicana, yet excepting their contemporary allopatric distributions, factors that contribute to reproductive isolation between this species pair remain uncharacterized. A previous report has shown reduced progeny numbers in laboratory crosses between the two species, especially when female D. novamexicana are crossed with male D. americana. We show that the hatch rate of eggs produced from heterospecific matings is reduced relative to conspecific matings. Failure of eggs to hatch, and consequent reduction in hybrid progeny number, is caused by low fertilization success of heterospecific sperm, thus representing a postmating, prezygotic incompatibility. Following insemination, storage and motility of heterospecific sperm is visibly compromised in female D. novamexicana. Our results provide evidence for a mechanism of reproductive isolation that is seldom reported for Drosophila species, and indicate the rapid evolution of postmating, prezygotic reproductive barriers in allopatry.
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Zambre, Amod M., Akshay Khandekar, Rajesh Sanap, Clairissa O'Brien, Emilie C. Snell-Rood, and Maria Thaker. "Asymmetric interspecific competition drives shifts in signalling traits in fan-throated lizards." Proceedings of the Royal Society B: Biological Sciences 287, no. 1940 (December 9, 2020): 20202141. http://dx.doi.org/10.1098/rspb.2020.2141.
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Interspecific competition can occur when species are unable to distinguish between conspecific and heterospecific mates or competitors when they occur in sympatry. Selection in response to interspecific competition can lead to shifts in signalling traits—a process called agonistic character displacement. In two fan-throated lizard species— Sitana laticeps and Sarada darwini —females are morphologically indistinguishable and male agonistic signalling behaviour is similar. Consequently, in areas where these species overlap, males engage in interspecific aggressive interactions. To test whether interspecific male aggression between Si. laticeps and Sa. darwini results in agonistic character displacement, we quantified species recognition and signalling behaviour using staged encounter assays with both conspecifics and heterospecifics across sympatric and allopatric populations of both species. We found an asymmetric pattern, wherein males of Si. laticeps but not Sa. darwini showed differences in competitor recognition and agonistic signalling traits (morphology and behaviour) in sympatry compared with allopatry. This asymmetric shift in traits is probably due to differences in competitive abilities between species and can minimize competitive interactions in zones of sympatry. Overall, our results support agonistic character displacement, and highlight the role of asymmetric interspecific competition in driving shifts in social signals.
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Pfennig, Karin S., and Michael J. Ryan. "Character displacement and the evolution of mate choice: an artificial neural network approach." Philosophical Transactions of the Royal Society B: Biological Sciences 362, no. 1479 (January 15, 2007): 411–19. http://dx.doi.org/10.1098/rstb.2006.1968.
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Interactions with heterospecifics can promote the evolution of divergent mating behaviours between populations that do and do not occur with heterospecifics. This process—reproductive character displacement—potentially results from selection to minimize the risk of mating with heterospecifics. We sought to determine whether heterospecific interactions lead to divergence of female preferences for aspects of conspecific male signals. We used artificial neural network models to simulate a mate recognition system in which females co-occur with different heterospecifics in different populations. Populations that evolved conspecific recognition in the presence of different heterospecifics varied in their preferences for aspects of conspecific male signals. When we tested networks for their preferences of conspecific versus heterospecific signals, however, we found that networks from allopatric populations were usually able to select against heterospecifics. We suggest that female preferences for aspects of conspecific male signals can result in a concomitant reduction in the likelihood that females will mate with heterospecifics. Consequently, even females in allopatry may discriminate against heterospecific mates depending on the nature of their preferences for conspecifics. Such a pattern could potentially explain cases where reproductive character displacement is expected, but not observed.
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Singh, B. N., and Sujata Chatterjee. "No character displacement for reproductive isolation between Drosophila bipectinata and Drosophila malerkotliana." Genome 34, no. 6 (December 1, 1991): 849–52. http://dx.doi.org/10.1139/g91-131.
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To test whether character displacement for reproductive isolation between Drosophila bipectinata and Drosophila malerkotliana exists, the degree of sexual isolation was measured between their sympatric and allopatric populations. Although the isolation indices vary in different crosses, the average isolation index for sympatric populations is very close to that for allopatric populations. This shows no difference in the degree of sexual isolation between sympatric and allopatric populations of D. bipectinata and D. malerkotliana. Thus there is no evidence for the existence of character displacement for sexual isolation between these two closely related sympatric species.Key words: Drosophila bipectinata, Drosophila malerkotliana, sexual isolation, sympatric and allopatric populations.
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Lachlan, R. F., and M. R. Servedio. "SONG LEARNING ACCELERATES ALLOPATRIC SPECIATION." Evolution 58, no. 9 (2004): 2049. http://dx.doi.org/10.1554/03-708.
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Hochstetter, Kurt. "Die Allopathie kommt uns näher." Allgemeine Homöopathische Zeitung 216, no. 06 (April 12, 2007): 260–63. http://dx.doi.org/10.1055/s-2006-935623.
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Schoeler, Heinz. "Die Allopathie kommt uns näher." Allgemeine Homöopathische Zeitung 216, no. 06 (April 12, 2007): 263–67. http://dx.doi.org/10.1055/s-2006-935624.
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Hoskin, Conrad J., Megan Higgie, Keith R. McDonald, and Craig Moritz. "Reinforcement drives rapid allopatric speciation." Nature 437, no. 7063 (October 2005): 1353–56. http://dx.doi.org/10.1038/nature04004.
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Lachlan, R. F., and M. R. Servedio. "SONG LEARNING ACCELERATES ALLOPATRIC SPECIATION." Evolution 58, no. 9 (September 2004): 2049–63. http://dx.doi.org/10.1111/j.0014-3820.2004.tb00489.x.
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Whitaker, Rachel J. "Allopatric origins of microbial species." Philosophical Transactions of the Royal Society B: Biological Sciences 361, no. 1475 (October 11, 2006): 1975–84. http://dx.doi.org/10.1098/rstb.2006.1927.
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Although allopatric divergence is a well-accepted mechanism of speciation for eukaryotic macro-organisms, the importance of geographical barriers to divergence in microbial populations is a subject of great debate. Do geographically separated populations of micro-organisms diverge independently, or does their structure fit the often quoted Bass-Becking description ‘everything is everywhere; the environment selects’? Aided by high-resolution genetic and genomic tools, the search for ‘microbial marsupials’ has revealed that in fact both are true; some species of micro-organisms demonstrate allopatric divergence, while others do not. This discovery opens the door for comparative analyses, where questions about the differences in evolutionary and ecological mechanisms that drive divergence and speciation in different microbial species can begin to be explored. Investigating these differences in evolutionary mechanisms will greatly enhance interest in, and understanding of, the dynamic processes that create and maintain the vast diversity of the microbial world.
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Arnal-Schnebelen, Bérengère. "Allopathie issue de la synthèse versus allopathie d’origine végétale: laquelle est la plus scientifique?" Phytotherapie 3, no. 4 (August 2005): 145–46. http://dx.doi.org/10.1007/s10298-005-0093-y.
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Doellman, Schuler, Jean, Hood, Egan, Powell, Glover, et al. "Geographic and Ecological Dimensions of Host Plant-Associated Genetic Differentiation and Speciation in the Rhagoletis cingulata (Diptera: Tephritidae) Sibling Species Group." Insects 10, no. 9 (August 29, 2019): 275. http://dx.doi.org/10.3390/insects10090275.
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Ascertaining the causes of adaptive radiation is central to understanding how new species arise and come to vary with their resources. The ecological theory posits adaptive radiation via divergent natural selection associated with novel resource use; an alternative suggests character displacement following speciation in allopatry and then secondary contact of reproductively isolated but ecologically similar species. Discriminating between hypotheses, therefore, requires the establishment of a key role for ecological diversification in initiating speciation versus a secondary role in facilitating co-existence. Here, we characterize patterns of genetic variation and postzygotic reproductive isolation for tephritid fruit flies in the Rhagoletis cingulata sibling species group to assess the significance of ecology, geography, and non-adaptive processes for their divergence. Our results support the ecological theory: no evidence for intrinsic postzygotic reproductive isolation was found between two populations of allopatric species, while nuclear-encoded microsatellites implied strong ecologically based reproductive isolation among sympatric species infesting different host plants. Analysis of mitochondrial DNA suggested, however, that cytoplasmic-related reproductive isolation may also exist between two geographically isolated populations within R cingulata. Thus, ecology associated with sympatric host shifts and cytoplasmic effects possibly associated with an endosymbiont may be the key initial drivers of the radiation of the R. cingulata group.
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Chilton, N. B., G. M. Morris, I. Beveridge, and G. Coulson. "Lack of evidence for co-speciation in a parasitic nematode of grey kangaroos." Journal of Helminthology 78, no. 3 (September 2004): 207–13. http://dx.doi.org/10.1079/joh2004240.
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AbstractMultilocus enzyme electrophoresis was used to compare specimens of the parasitic nematode Cloacina obtusa from the stomach of the eastern grey kangaroo, Macropus giganteus and the western grey kangaroo, M. fuliginosus. Allelic variation among nematodes was detected at 17 (85%) of 20 loci, but there was only a single fixed genetic difference (at the locus for isocitrate dehydrogenase, IDH) between C. obtusa from M. fuliginosus and those from M. giganteus in areas where each host occurred in allopatry. However, this fixed difference was not apparent within the zone of host sympatry. Although electrophoretic data indicate genetic divergence among allopatric populations of C. obtusa in the two host species, the magnitude of the electrophoretic difference (5%) between these populations does not refute the hypothesis that C. obtusa represents a single species. The ’usual’ situation for parasitic helminths of grey kangaroos is that pairs of parasite species occur in the two host species. This situation differs for C. obtusa, where there has been a lack of speciation following a speciation event in its macropodid marsupial hosts. This finding suggests that a speciation event in the host does not necessarily lead to a speciation event for all its parasites and further highlights our lack of understanding of which processes drive speciation in parasites.
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McPhail, J. D. "Ecology and evolution of sympatric sticklebacks (Gasterosteus): origin of the species pairs." Canadian Journal of Zoology 71, no. 3 (March 1, 1993): 515–23. http://dx.doi.org/10.1139/z93-072.
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Pairs of plankton-feeding and benthos-foraging sticklebacks (Gasterosteus aculeatus) (limnetics and benthics) coexist in six small lakes in southwestern British Columbia. In spite of a persistent low level of hybridization the pairs maintain themselves as distinct genetic and ecological entities; because of this they are viewed as biological species. They appear to be restricted to the central Strait of Georgia region, and the geological history of the area argues that they are of postglacial origin. The pairs occur on three islands (Vancouver, Texada, and Lasqueti), but even on these islands they are not found in all available lakes. Both lake morphometry (size and depth) and altitude appear to influence local distribution. Hypotheses that might explain the origin of the pairs are examined. Neither theory nor data support a sympatric origin, but an allopatric origin through two invasions of marine sticklebacks is consistent with both the geological history of the area and the details of local distribution. An independent but parallel evolution of the pairs on at least two islands (Vancouver and Texada) is implicit in this hypothesis. The hypothesis also assumes that although the initial divergence started in allopatry, competitive interactions in sympatry played a major role in the evolution of reproductive isolation and resource partitioning.
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Pillay, Neville. "FEMALE MATE PREFERENCE AND REPRODUCTIVE ISOLATION IN POPULATIONS OF THE STRIPED MOUSE RHABDOMYS PUMILIO." Behaviour 137, no. 11 (2000): 1431–41. http://dx.doi.org/10.1163/156853900502655.
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AbstractLaboratory experiments were conducted to study female mate preference in three allopatric populations of the striped mouse Rhabdomys pumilio, an African murid rodent. The three populations (Alice, Goegap, Irene) represent the extremes of the distribution range of the species in South Africa. Using two-way choice tests, virgin females were exposed to: (i) males of the same population (homotype) and those of another population (heterotype) in whole animal choice tests, or (ii) the odiferous bedding of homotype and heterotype males. Generally, females significantly preferred homotype stimulus males or their odour. This preference was only evident when females were in oestrus, suggesting that females were choosing potential mates. In addition, prior association with males is not needed for the establishment of female mate preference, since females were never exposed to adult males of any of the populations prior to testing. The only exception was receptive Goegap females which showed equal preference for homotype and Alice heterotype males. Mate preference in these two populations is asymmetric since Alice females showed strong preference for homotype males over Goegap males. The results indicate that divergence has occurred in allopatry, resulting in populationspecific communication signals and in particular olfactory cues, assortative mate choice, and pre-mating reproductive isolation.
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Pereira, Renato Crespo, Daniela Bueno Sudatti, Thaise S. G. Moreira, and Carlos Renato R. Ventura. "Chemical defense in developmental stages and adult of the sea star Echinaster (Othilia) brasiliensis." PeerJ 9 (June 18, 2021): e11503. http://dx.doi.org/10.7717/peerj.11503.
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To date, evidence regarding the performance of secondary metabolites from larval stages of sea stars as an anti-predation defense relates only to a few species/specimens from a few geographic ranges. Unfortunately, this hinders a comprehensive global understanding of this inter-specific predator-prey interaction. Here, we present laboratory experimental evidence of chemical defense action in the early developmental stages and adults of the sea star Echinaster (Othilia) brasiliensis from Brazil against sympatric and allopatric invertebrate consumers. Blastulae, early and late brachiolarias of E. (O.) brasiliensis were not consumed by the sympatric and allopatric crabs Mithraculus forceps. Blastulae were also avoided by the sympatric and allopatric individuals of the anemone Anemonia sargassensis, but not the larval stages. Extracts from embryos (blastula) and brachiolarias of E. (O.) brasiliensis from one sampled population (João Fernandes beach) significantly inhibited the consumption by sympatric M. forceps, but not by allopatric crabs and A. sargassensi anemone. In this same site, extracts from adults E. (O.) brasiliensis significantly inhibited the consumption by sympatric and allopatric specimens of the crab in a range of concentrations. Whereas equivalent extract concentrations of E. (O.) brasiliensis from other population (Itaipu beach)inhibited the predation by allopatric M. forceps, while sympatric individuals of this crab avoided the only the higher level tested. Then, early stages and adult specimens of E. (O.) brasiliensis can be chemically defended against consumers, but this action is quite variable, depending on the type (anemone or crab) and the origin of the consumer (sympatric or allopatric).
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Horwitz, P., M. Adams, and P. Baverstock. "Electrophoretic contributions to the systematics of the freshwater crayfish genus Engaeus Erichson (Decapoda : Parastacidae)." Invertebrate Systematics 4, no. 3 (1990): 615. http://dx.doi.org/10.1071/it9900615.
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As part of an examination into the systematics of the freshwater crayfish genus Engaeus, an electrophoretic evaluation of specimens from a large number of collecting sites has been undertaken. From a total of 76 sample sets, a minimum of 30 distinct biological species have been delineated. Strong evidence from sites of both sympatry and allopatry suggests some further delineations of species but these must await additional discriminatory information. Sympatric species were detected on 11 separate occasions. In each case, fixed allelic differences were found, indicating an absence of interbreeding between each sympatric pair. Allopatric species were delineated where genetic differences between populations exceeded a threshold level determined from observed genetic differences between sympatric Engaeus species and between other (mainly decapod) species in the literature. The results of this analysis have confirmed low levels of heterozygosity in Engaeus species. Frequent isoIation of small populations of Engaeus species, and consequent loss of allelic variation, is suggested as a possible cause of these low levels. Some species have shown variation of allelic frequencies over their geographical range and, in some cases, this variation could be interpreted as showing clinal properties. Finally, the electrophoretic data have been interpreted to produce some information regarding the phylogenetic affinities of delineated species. Several groups of species were found which shared closer intra-group relationships than they did to the other species of Engaeus.
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Vargas, Oscar M., Santiago Madriñán, and Beryl Simpson. "Allopatric speciation is more prevalent than parapatric ecological divergence in a recent high-Andean diversification (Linochilus: Asteraceae)." PeerJ 11 (June 9, 2023): e15479. http://dx.doi.org/10.7717/peerj.15479.
Full textAbstract:
Elucidating how species accumulate in diversity hotspots is an ongoing debate in evolutionary biology. The páramo, in the Northern Andes, has remarkably high indices of plant diversity, endemicity, and diversification rates. A hypothesis for explaining such indices is that allopatric speciation is high in the páramo given its island-like distribution. An alternative hypothesis is that the altitudinal gradient of the Andean topography provides a variety of niches that drive vertical parapatric ecological speciation. A formal test for evaluating the relative roles of allopatric and parapatric ecological speciation is lacking. The main aim of our study is to test which kind of speciation is more common in an endemic páramo genus. We developed a framework incorporating phylogenetics, species’ distributions, and a morpho-ecological trait (leaf area) to compare sister species and infer whether allopatric or parapatric ecological divergence caused their speciation. We applied our framework to the species-rich genus Linochilus (63 spp.) and found that the majority of recent speciation events in it (12 events, 80%) have been driven by allopatric speciation, while a smaller fraction (one event, 6.7%) is attributed to parapatric ecological speciation; two pairs of sister species produced inconclusive results (13.3%). We conclude that páramo autochthonous (in-situ) diversification has been primarily driven by allopatric speciation.
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Bird, Stephen R., and Robert Semeonoff. "Selection for oviposition preference in Drosophila melanogaster." Genetical Research 48, no. 3 (December 1986): 151–60. http://dx.doi.org/10.1017/s0016672300024940.
Full textAbstract:
SummaryPopulations of Drosophila melanogaster were subjected to selection for differing oviposition preference under allopatric and sympatric conditions. Flies were presented with the choice of a potato-based medium and a medium containing sugar and killed yeast on which to lay their eggs. Some gene flow was possible under sympatric conditions. In the allopatric lines selection was successful in rapidly generating an increased preference for sugar, and in the sympatric lines divergent oviposition preferences were generated in two cases out of four. A significant degree of reproductive isolation between one pair of allopatric lines was generated after eighteen months of selection.
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Yamaguchi, Ryo, and Yoh Iwasa. "First passage time to allopatric speciation." Interface Focus 3, no. 6 (December 6, 2013): 20130026. http://dx.doi.org/10.1098/rsfs.2013.0026.
Full textAbstract:
Allopatric speciation is a mechanism to evolve reproductive isolation; it is caused by the accumulation of genetic differences between populations while they are geographically isolated. Here, we studied a simple stochastic model for the time until speciation caused by geographical isolation in fragmented populations that experience recurrent but infrequent migration between subpopulations. We assumed that mating incompatibility is controlled by a number of loci that behave as neutral characters in the accumulation of novel mutations within each population. Genetic distance between populations was defined as the number of incompatibility-controlling loci that differ between them. Genetic distance increases through the separate accumulation of mutations in different populations, but decreases after a successful migration event followed by genetic mixing between migrants and residents. We calculated the time to allopatric speciation, which occurs when the genetic distance exceeds a specified threshold. If the number of invasive individuals relative to the resident population is not very large, diffusion approximation provides an accurate prediction. There is an intermediate optimal rate of migration that maximizes the rate of species creation by recurrent invasion and diversification. We also examined cases that involved more than two populations.