Contemporary Parallel Diversification, Antipredator Adaptations and Phenotypic Integration in an Aquatic Isopod

It is increasingly being recognized that predation can be a strong diversifying agent promoting ecological divergence. Adaptations against different predatory regimes can emerge over short periods of time and include many different traits. We studied antipredator adaptations in two ecotypes of an isopod (Asellus aquaticus) that have, diverged in parallel in two Swedish lakes over the last two decades. We quantified differences in escape speed, morphology and behavior for isopods from different ecotypes present in these lakes. Isopods from the source habitat (reed) coexist with mainly invertebrate predators. They are more stream-profiled and have higher escape speeds than isopods in the newly colonized stonewort habitat, which has higher density of fish predators. Stonewort isopods also show more cautious behaviors and had higher levels of phenotypic integration between coloration and morphological traits than the reed isopods. Colonization of a novel habitat with a different predation regime has thus strengthened the correlations between pigmentation and morphology and weakened escape performance. The strong signature of parallelism for these phenotypic traits indicates that divergence is likely to be adaptive and is likely to have been driven by differences in predatory regimes. Furthermore, our results indicate that physical performance, behavior and morphology can change rapidly and in concert as new habitats are colonized

The odonate phenotypic database, a new open data resource for comparative studies of an old insect order

Funding Information: We would like to acknowledge the students and laboratory assistants that helped us to collect the data from the literature, and in particular Anna Kell, Ev Poslin, Hanna Bensch, Robin Pranter, Kajsa Svensson, Lisa Winberg, Karolina Pehrson, Mireia Balesta and Tammy Ho. We would like to also thank the many authors of the field guides from which our database references. Our database is by no means nor intends to be a substitute for these valuable books. Funding for this study have been provided by research grants from The Swedish Research Council (VR: grant no. 2016-03356), Gyllenstiernska Krapperupstiftelsen (grant no. KR2018-0038) and Olle Engqvist Byggmästares Stiftelse to E.I.S. and from a Faculty Mobility grant from the University of Costa Rica and a grant from the Schlumberger Foundation to B.W. Open access funding provided by Lund University.Peer reviewe

Island biology and morphological divergence of the Skyros wall lizard Podarcis gaigeae: a combined role for local selection and genetic drift on color morph frequency divergence?

<p>Abstract</p> <p>Background</p> <p>Patterns of spatial variation in discrete phenotypic traits can be used to draw inferences about the adaptive significance of traits and evolutionary processes, especially when compared to patterns of neutral genetic variation. Population divergence in adaptive traits such as color morphs can be influenced by both local ecology and stochastic factors such as genetic drift or founder events. Here, we use quantitative color measurements of males and females of Skyros wall lizard, <it>Podarcis gaigeae</it>, to demonstrate that this species is polymorphic with respect to throat color, and the morphs form discrete phenotypic clusters with limited overlap between categories. We use divergence in throat color morph frequencies and compare that to neutral genetic variation to infer the evolutionary processes acting on islet- and mainland populations.</p> <p>Results</p> <p>Geographically close islet- and mainland populations of the Skyros wall lizard exhibit strong divergence in throat color morph frequencies. Population variation in throat color morph frequencies between islets was higher than that between mainland populations, and the effective population sizes on the islets were small (N_e:s < 100). Population divergence (F_ST) for throat color morph frequencies fell within the neutral F_ST-distribution estimated from microsatellite markers, and genetic drift could thus not be rejected as an explanation for the pattern. Moreover, for both comparisons among mainland-mainland population pairs and between mainland-islet population pairs, morph frequency divergence was significantly correlated with neutral divergence, further pointing to some role for genetic drift in divergence also at the phenotypic level of throat color morphs.</p> <p>Conclusions</p> <p>Genetic drift could not be rejected as an explanation for the pattern of population divergence in morph frequencies. In spite of an expected stabilising selection, throat color frequencies diverged in the islet populations. These results suggest that there is an interaction between selection and genetic drift causing divergence even at a phenotypic level in these small, subdivided populations.</p

Sexual selection on wing interference patterns in Drosophila melanogaster

Animals with color vision use color information in intra- and interspecific communication, which in turn may drive the evolution of conspicuous colored body traits via natural and sexual selection. A recent study found that the transparent wings of small flies and wasps in lower-reflectance light environments display vivid and stable structural color patterns, called “wing interference patterns” (WIPs). Such WIPs were hypothesized to function in sexual selection among small insects with wing displays, but this has not been experimentally verified. Here, to our knowledge we present the first experimental evidence that WIPs in males of Drosophila melanogaster are targets of mate choice from females, and that two different color traits—saturation and hue—experience directional and stabilizing sexual selection, respectively. Using isogenic lines from the D. melanogaster Genetic Reference Panel, we compare attractiveness of different male WIPs against black and white visual backgrounds. We show that males with more vivid wings are more attractive to females than are males with dull wings. Wings with a large magenta area (i.e., intermediate trait values) were also preferred over those with a large blue or yellow area. These experimental results add a visual element to the Drosophila mating array, integrating sexual selection with elements of genetics and evo-devo, potentially applicable to a wide array of small insects with hyaline wings. Our results further underscore that the mode of sexual selection on such visual signals can differ profoundly between different color components, in this case hue and saturation

Signatures of local adaptation along environmental gradients in a range-expanding damselfly (Ischnura elegans)

ACKNOWLEDGEMENTSThis work was supported by an EU FP7, Marie Curie International Incoming Fellowship (to RYD; project code “MOVE2ADAPT”), a Wenner-Gren Foundation Postdoctoral Stipend (to RYD), the Oscar and Lili Lamm Foundation (to RYD, BH), Biodiversity and Ecosystem Services in a Changing Climate (BECC; a joint Lund–Gothenburg University initiative) (LL), the Swedish Research Council (EIS, BH),the Crafoord Foundation (EIS, BH) and Erik Philip-Sorensens Stiftelse (E.I.S.). We would like to thank Hanna Bensch and Paul Caplat for assistance with the collection of samples in the field and the Grimso Research Station and Mikael Akesson for logistical support. Wethank Pallavi Chauhan for assistance with SNP annotation. We thank Martin Andersson for assistance with DNA extraction, Jane Jonssonfor laboratory administration, and Julian Catchen, Martin Stervander, Dag Ahren and Maren Wellenreuther for bioinformatics advice and helpful discussion.Peer reviewedPostprin

Opsin gene expression plasticity and spectral sensitivity as mechanisms for search image formation in mate-searching male damselflies

ABSTRACTOdonata (damselflies and dragonflies) are a largely diurnal, colourful, and strongly visually guided group of insects with visual systems influenced by many opsin genes that form the primary light-sensitive eye photopigments. Heritable (genetic) female-limited colour polymorphisms are also common in Odonata, with one female morph typically exhibiting male-like (androchrome) colouration and one or two morphs exhibiting female-specific colouration (gynochromes). In the Common Bluetail Damselfly (Ischnura elegans), androchrome females express blue body colouration similar to that of mature males while gynochrome females express either green or red-brown colouration. This and other colour polymorphisms in damselflies are thought to be maintained by male mating harassment and frequency-dependent sexual conflict, in which males form search images for certain morphs which suffer disproportionally from mating harassment. Here, we investigate the role of opsin sensitivity and expression plasticity in visual mate detection inI. elegansby quantifying relative opsin mRNA expression over adult maturation in populations with different female morph frequencies in southern Sweden. We find evidence for opsin-specific plasticity in relative and proportion opsin expression, suggesting changes in opsin regulation and visual sensitivity over adult maturation. Furthermore, the relative expression of the long-wavelength sensitive opsin LWF2 changed in response to female morph frequencies. The highest relative expression levels were found in populations with either a high or low proportion of androchrome females.In vitroresults indicate that long-wavelength sensitive opsins inI. elegansprovide a good visual match to the colouration of green gynomorph females and could in principle confer male colour discrimination between female morphs. We discuss these results in relation to frequency dependent selection, male sensory adaptations, plastic search images and mate searching costs. We suggest that opsin gene expression could play an important role in male search image formation of suitable mates

In Memoriam : Barry Sinervo 1961-2021

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Human influences on evolution, and the ecological and societal consequences.

Humans have dramatic, diverse and far-reaching influences on the evolution of other organisms. Numerous examples of this human-induced contemporary evolution have been reported in a number of 'contexts', including hunting, harvesting, fishing, agriculture, medicine, climate change, pollution, eutrophication, urbanization, habitat fragmentation, biological invasions and emerging/disappearing diseases. Although numerous papers, journal special issues and books have addressed each of these contexts individually, the time has come to consider them together and thereby seek important similarities and differences. The goal of this special issue, and this introductory paper, is to promote and expand this nascent integration. We first develop predictions as to which human contexts might cause the strongest and most consistent directional selection, the greatest changes in evolutionary potential, the greatest genetic (as opposed to plastic) changes and the greatest effects on evolutionary diversification We then develop predictions as to the contexts where human-induced evolutionary changes might have the strongest effects on the population dynamics of the focal evolving species, the structure of their communities, the functions of their ecosystems and the benefits and costs for human societies. These qualitative predictions are intended as a rallying point for broader and more detailed future discussions of how human influences shape evolution, and how that evolution then influences species traits, biodiversity, ecosystems and humans.This article is part of the themed issue 'Human influences on evolution, and the ecological and societal consequences'.APH is primarily funded by a Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery Grant. KMG is supported by a Le Fonds Québécois de la Recherche sur la Nature et les Technologies (FQRNT) Postdoctoral Fellowship. EIS is supported by the Swedish Research Council (Vetenskapsrådet; VR) and Erik Philip Sörenssons Stiftelse.This is the author accepted manuscript. The final version is available from The Royal Society via https://doi.org/10.1098/rstb.2016.002

Latitudinal clines in sexual selection, sexual size dimorphism, and sex-specific genetic dispersal during a poleward range expansion

Acknowledgements This work was supported by Macquarie University (to AC, RYD), an EU FP7, Marie Curie International Incoming Fellowship (to RYD, BH; project code ‘MOVE2ADAPT’), a WennerGren Foundation Postdoctoral Stipend (to RYD, BH), the Oscar and Lili Lamm Foundation (to RYD, BH), Biodiversity and Ecosystem Services in a Changing Climate (BECC; a joint LundGothenburg University initiative) (to LL, BH), the Swedish Research Council (to EIS, BH (2014-5222, 2016-689)), the Crafoord Foundation, “Stina Werners Stiftelse” and “Erik Philip Sörensens Stiftelse” (to EIS). We thank Hanna Bensch, John Waller, Paul Caplat and Martin Andersson for field and lab assistance, the Grimsö Research Station and Mikael Åkesson for field support and Sonu Yadav for analysis advice. We thank Julian Catchen, Martin Stervander and Dag Ahren for bioinformatics advice and Maren Wellenreuther for helpful discussion.Peer reviewedPostprin