Abstracts (first author)

Talk 

Ecology and mating interactions: temperature influences male-female conflict in a colour polymorphic damselfly

Author(s): Svensson E

Summary:

Heritable and conspicuous colour polymorphisms have a long research tradition in ecological genetics, and these systems have been used to investigate issues such as negative-frequency-dependent selection (NFDS), maintenance of genetic variation, sexual selection and sexual conflict. Here I will present long-term field observational data and experiments on the evolutionary dynamics of a sexually selected colour polymorphism in the damselfly Ischnura elegans. Three female morphs exist in this species, one of them being a male mimic ("androchrome females"). Androchrome have lower mating rates than other female morphs, suggesting that male mimicry is a female defence against excessive and costly male mating harassment that is detrimental to female fitness. I will present long-term field data from a longitudinal study across multiple populations that show the stability of this female polymorphism and the results of experiments where we have manipulated morph frequencies and densities and evaluated the effects on morph and population fitnesses. I will also present data showing that the male-female mating interactions are environment-dependent and moulded by ambient temperatures, resulting in geographic variation in morph frequencies. Thus, sexual conflict in this system and the benefits of male mimicry is highly context-dependent upon local ecology and the thermal environment.


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Abstracts (coauthor)

Summary:

Sexual selection is thought to lead to sexual dimorphism, following a transitional stage where both sexes have similar phenotypes due to a shared genetic architecture. In addition, sexual selection might facilitate both speciation and possibly also extinction. However, our knowledge about how the environment shapes sexual selection regimes and how ecology and sexual selection interact is still limited. Here we report the results from a study on the evolution of wing pigmentation in calopterygid damselflies. We investigated the effects of sexual selection on sexual dimorphism, speciation and extinction and the possible thermoregulatory consequences of wing pigmentation using a mixture of phylogenetic comparative analyses, field data and experiments . First, we traced the evolution of wing pigmentation and reconstructed ancestral states of male and female phenotypes. Our results indicate that clear wings are the ancestral state, that pigmentation is costly to females and sexual selection results in sexual dimorphism. We further demonstrate that pigmentation elevates speciation rates and tends to also elevate extinction rates. We document a significant biogeographic association with pigmented species primarily occupying northern temperate regions with cooler climates. Field observations and experiments on two temperate sympatric species suggest an interaction between pigmentation, thermoregulation and sexual selection, although body temperature is also likely to be influenced by other phenotypic traits such as body mass, microhabitat selection and thermoregulatory behaviors. Taken together, our results suggest an important role for wing pigmentation in speciation and sexual selection in males, but with a net cost to females. However, wing pigmentation does not necessarily increase ecological adaptation and species longevity, and its primary function therefore lies in sexual signalling and species recognition.

Fewer invited talks by women in evolutionary biology: men accept invitations to speak more often than women

Author(s): Dugdale, HL, Schroeder J, Radersma R, Hinsch M, Buehler DM, Saul J, Porter L, Liker A, De Cauwer I, Johnson PJ, Santure AW, Griffin AS, Bolund E, Ross L, Webb TJ, Feulner PGD, Winney I, Szulkin M, Komdeur J, Versteegh MA, Hemelrijk CK, Svensson EI, Edwards H, Karlsson M, West SA, Barrett ELB, Richardson DS, Van den Brink V, Wimpenny JH, Ellwood SA, Rees M, Matson KD, Charmantier A, Dos Remedios N, Schneider NA, Teplitsky C, Laurance WF, Butlin RK, Horrocks NP

Summary:

Lower ‘visibility’ of female scientists, compared to male scientists, is a potential reason for the under-representation of women among senior academic ranks. Visibility in the scientific community stems partly from presenting research as an invited speaker at organised meetings. We analysed the sex ratio of presenters at the European Society for Evolutionary Biology Congress 2011, where all abstract submissions were accepted for presentation. Women were under-represented among invited speakers at symposia (15% women) compared to all presenters (46%), regular oral presenters (41%) and plenary speakers (25%). At the ESEB congresses in 2001–2011, 8–23% of invited speakers were women. This under-representation of women is partly attributable to a larger proportion of women, than men, declining invitations: in 2011, 50% of women declined an invitation to speak compared to 26% of men. We expect invited speakers to be senior scientists or authors of recent papers in high-impact journals. Considering all invited speakers (including declined invitations), 23% were women. This was lower than the baseline sex ratios of early–mid career stage scientists, but was similar to senior scientists and authors published in high-impact journals. High-quality science by women therefore has low exposure at international meetings, which will constrain Evolutionary Biology from reaching its full potential. We wish to highlight the wider implications of turning down invitations to speak. In particular, under-representation of women among invited speakers reduces the number of female role models for evolutionary biology students and contributes to the leaky pipeline. We encourage conference organisers to implement steps to increase acceptance rates of invited talks.

Summary:

Assortative mating occurs when individuals in a population mate non-randomly and there is a correlation with respect to traits between individuals in mated pairs. It is important in evolutionary processes in that if selection acts on the same trait, assortative mating may lead to speciation and reproductive isolation. On the other hand, if assortative mating is free of selection, it will lead to stabilizing selection within a population. In this study, I examined assortative mating strength within and between two sympatric damselfly species (Calopteryx splendens and Calopteryx virgo) by correlating the male and female morphological characters in mated pairs. In addition, I investigated the relationship between assortative mating and sexual selection (linear, β and quadratic, γ) on the same traits for these damselfly species. In both species, positive assortative mating was more common than negative assortment (disassortative mating). Thorax width in both species had the greatest assortative mating strength. There was no relationship between assortative mating strength and linear selection or quadratic selection. This indicates that there is no strong connection between assortative mating and sexual selection on the same traits. Assortative mating strength for C. splendens and C. virgo were concordant, and positive, suggesting that there is no noticeable reproductive isolation between these two species and that stabilizing selection is probably operating. Rather, assortment in both species is based on quality, where high-quality males get high-quality females. This study contributes to the knowledge about evolution and selection in natural populations.

Summary:

Wing interference patterns (WIPs) are a newly discovered trait in Drosophila, and are caused by thin-film interference of light on the wing surfaces. Only 10-12% of the incident light on the wing is reflected as a WIP, so these patterns are only visible against a dark background. This is also the reason WIPs are a previously overlooked (i.e. cryptic) trait. We have carried out the first comprehensive study of WIPs in Drosophila, and have been able to confirm that although WIPs are influenced by wing size, there is a large genetic component to WIP variation. We have also carried out a manipulative mate choice experiment, where female preference for different WIP phenotypes was tested against light and dark backgrounds. We found that there was a significant effect of WIPs on female preference in the dark background, providing the first evidence that WIPs are a cryptic sexually selected trait in Drosophila melanogaster.

Contacts

Chairman: Octávio S. Paulo
Tel: 00 351 217500614 direct
Tel: 00 351 217500000 ext22359
Fax: 00 351 217500028
email: mail@eseb2013.com

Address

XIV Congress of the European Society for Evolutionary Biology

Organization Team
Department of Animal Biology (DBA)
Faculty of Sciences of the University of Lisbon
P-1749-016 Lisbon
Portugal

Website

Computational Biology & Population Genomics Group 
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