EXEB meeting on Tuesday April 15: Visit by Wiebke Feindt and talk about comparative transcriptomics in Neotropical damselflies

Posted by Erik Svensson

 For next week's EXEB-meeting, I am pleased to welcome Wiebke Feindt from ITZ Division of Ecology & Evolution in Hannover (Germany). Wiebke is currently doing a PhD on evolution, conservation genetics and comparative transcriptomics of Neotropical odonates. She is particularly interested in the charismatic genus Megaloprepus, which contains the largest damselflies in the world and which are often called "Helicopter damselflies". Below is the title of Wiebke's talk and a brief Abstract.

Odonate speciation in the Neotropics: New insights into the genus Megaloprepus

In an ever-changing world flying insects play a significant role for studying speciation. As the world’s largest living odonate species, Megaloprepus caerulatus is an excellent model organism to investigate this crucial point of evolution. Despite its niche conservatism, a strong genetic differentiation and a morphometric separation into four distinct clusters was detected. On this basis, ongoing comparative transcriptomics may further contribute to elucidate the complex evolutionary processes and causal interplays of speciation.

Time: Tuesday, March 15, 2016, at 10.00

Locale: "Argumentet", 2nd floor, Ecology Building

"Entomology Futures" - Minisymposium on insect ecology and evolution

  Posted by Erik Svensson

Next week EXEB will co-organize a Minisymposium together with The Pheromone Group at the Biology Department in Lund entitled "Entomology Futures", which will focus on insect ecology and evolution.

This symposium is organized in conjunction with the visit by Dr. Niklas Wahlberg from University of Turkku in Finland to our department. Wahlberg is a leading phylogeneticist and systematist who mainly works on butterflies, but has broad ranging research interests in evolutionary biology and entomology.

The symposium is open for everyone interested, although the locality is small and can only take 20-25 attendants, meaning that you should aim to arrive early.

When: Wednesday March 5 2014, 14.00-16.00
Where: Seminar room "Tanken", 1st floor, Ecology Building

Scientific Program

14.00 - 14.30 Niklas Wahlberg: The 215 million years of Lepidoptera diversification: lessons from an ever changing world

14.30 - 15.00 Jadranka Rota: Behavioural ecology and systematics of metalmark moths (Lepidoptera: Choreutidae)

15.00 - 15.20 Coffee break

15.20 - 15.40 Machteld Verzijden: Courtship and mate preference functions are jointly shaped by geographic variation in developmental plasticity and interspecific interactions

15.40 - 16.00 Jessica Abbott: G x E effects of diet on male fitness in Drosophila melanogaster: phenotypic plasticity, or genetic robustness?

On linking ecology to sexual selection

Together with John Waller, I have a paper that is now out in American Naturalist as an E-article, meaning that it is "Open Acess" and possible for anyone to download. Go here, if you would like to download a PDF of this paper. I am very much in favour of the OA-model of publishing, and I certainly hope that the publication fees we paid will also result in more citations.

This study, which was fun to do and write up, takes a look at the important link between ecology and sexual selection. We were interested in the functional significance and evolutionary consequences of wing pigmentation in calopterygid damselflies, and we used a mixture of comparative phylogenetic analyses and field studies using thermal imaging to adress this issue. In particular, we wanted to see if there was any obvious thermal benefit of male wing pigmentation, which also has important functions in sexual selection, male-male competition and species recognition. Turns out that the evidence for such a thermal benefit is mixed, although there is a clear biogeographic signature in the sense that pigmented clades are more common in northern regions and temperate climates.

Wing pigmentation is also significantly associated with eleved speciation and extinction rates, using so-called BiSSE-analyses ("Binary Speciation and Extinction") as implemented in Diversitree. This latter result provides comparative support to our previous experimental work demonstrating that wing pigmentation functions as a species recognition character between C. splendens and C. virgo, and suggest that wing pigmentation is generally involved across the entire group as a promoter of speciation, although most species formed by such non-ecological sexual selection tend to go extinct fairly soon after they have formed.

In general, I think there are too few studies where comparative approaches and field experiments are combined, as both have strength and weaknesses and inferences could be stronger if they are combined (Disclaimer: in case some sensitive theoretical ecologist reads this post, I do of course also think there are other interesting and useful research approaches, such as mathematical models).

Ecology and Sexual Selection: Evolution of Wing Pigmentation in Calopterygid Damselflies in Relation to Latitude, Sexual Dimorphism, and Speciation

American Naturalist (in press, November 2013)

Erik I. Svensson* and John T. Waller

Evolutionary Ecology Unit, Department of Biology, Lund University, SE-223 62 Lund, Sweden

Abstract

Our knowledge about how the environment influences sexual selection regimes and how ecology and sexual selection interact is still limited. We performed an integrative study of wing pigmentation in calopterygid damselflies, combining phylogenetic comparative analyses, field observations and experiments. We investigated the evolutionary consequences of wing pigmentation for sexual dimorphism, speciation, and extinction and addressed the possible thermoregulatory benefits of pigmentation. First, we reconstructed ancestral states of male and female phenotypes and traced the evolutionary change of wing pigmentation. Clear wings are the ancestral state and that pigmentation dimorphism is derived, suggesting that sexual selection results in sexual dimorphism. We further demonstrate that pigmentation elevates speciation and extinction rates. We also 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 a link between pigmentation, thermoregulation, and sexual selection, although body temperature is also affected 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 sexual selection in males and in speciation. Wing pigmentation might not increase ecological adaptation and species longevity, and its primary function is in sexual signaling and species recognition.

First lab-meeting 8 January 2013: Evolution of sex differences in canalization and plasticity

Male pheasant (Phasanius colchicus), a sexually very dimorphic bird. 

Photo: Erik Svensson

Posted by Erik Svensson

It is time for the first lab-meeting of 2013, and since it will be my birthday (8 January), I will bring a cake. I want to dedicate this lab-meeting to two papers about sex differences in plasticity and its opposite (canalization). You will find the Abstracts below, and you can download these two papers here and here.

I do also want to take the opportunity to briefly (15-30 minutes) present some ongoing work that I have been doing with Machteld, Maren and Anna Runemark about sex-differences in learned mate preferences and responses to heterospecifics, based on some experiments we have done on male and female banded demoiselles (Calopteryx splendens). This is also related to some of Machtelds ongoing work on the developmental plasticity of preference curves and mate preference learning, which we can also discuss a bit. Hopefully, there will then be a smooth transition between this short presentation and the papers we will discuss.

For the rest of the semester, Machteld Verzijden (machteld.verzijden@biol.lu.se) is responsible for setting up a "Google Docs"-link soon so that we can all sign up for lab-meetings and take the opportunity to arrange at least one lab-meeting during next semester (including picking 1-2 papers and/or prepare a presentation, bring fika, writeup a blog post, post it on the Facebook group).

Details about the lab-meeting next week:

Time: 8 January 2013 at 10.30
Place: "Argumentet", 2nd floor, Ecology Building

Sex Differences in Phenotypic Plasticity Affect Variation in Sexual Size Dimorphism in Insects: From Physiology to Evolution

Annual Review of Entomology

Vol. 55: 227-245 (Volume publication date January 2010)

R. Craig Stillwell, Wolf U. Blanckenhorn, Tiit Teder, Goggy Davidowitz, and Charles W. Fox  
Males and females of nearly all animals differ in their body size, a phenomenon called sexual size dimorphism (SSD). The degree and direction of SSD vary considerably among taxa, including among populations within species. A considerable amount of this variation is due to sex differences in body size plasticity. We examine how variation in these sex differences is generated by exploring sex differences in plasticity in growth rate and development time and the physiological regulation of these differences (e.g., sex differences in regulation by the endocrine system). We explore adaptive hypotheses proposed to explain sex differences in plasticity, including those that predict that plasticity will be lowest for traits under strong selection (adaptive canalization) or greatest for traits under strong directional selection (condition dependence), but few studies have tested these hypotheses. Studies that combine proximate and ultimate mechanisms offer great promise for understanding variation in SSD and sex differences in body size plasticity in insects.

CONTRASTING THEORY WITH THE EMPIRICAL DATA OF SPECIES RECOGNITION

Author(s): Ord, T.J.; King, L, Young, A.R.

Evolution Volume: 65   Issue: 9   Pages: 2572-2591   DOI: 10.1111/j.1558-5646.2011.01319.x   Published: SEP 2011

Abstract: We tested hypotheses on how animals should respond to heterospecifics encountered in the environment. Hypotheses were formulated from models parameterized to emphasize four factors that are expected to influence species discrimination: mating and territorial interactions; sex differences in resource value; environments in which heterospecifics were common or rare; and the type of identity cues available for species recognition. We also considered the role of phylogeny on contemporary responses to heterospecifics. We tested the extent these factors explained variation among taxa in species discrimination using a meta-analysis of three decades of species recognition research. A surprising outcome was the absence of a general predictor of when species discrimination would most likely occur. Instead, species discrimination is dictated by the benefits and costs of responding to a conspecific or heterospecific that are governed by the specific circumstances of a given species. The phylogeny of species recognition provided another unexpected finding: the evolutionary relationships among species predicted whether courting males within species-but not females-would discriminate against heterospecifcs. This implies that species recognition has evolved quite differently in the sexes. Finally, we identify common pitfalls in experimental design that seem to have affected some studies (e.g., poor statistical power) and provide recommendations for future research.

Welcome Lesley Lancaster, our new postdoc

I am pleased to welcome Lesley Lancaster, our new incoming postdoc, funded by BECC ("Biodiversity and Ecosystem Services in Changing Climate"). Lesley will arrive to Lund in late May or early June, and she will work with me and Bengt Hansson on the population genetics and ecology of range limit evolution, particularly using our favourite model organism: the damselfly Ischnura elegans ("Common Bluetail") as the main study object. Both Bengt and I are very excited about this project and about recruiting Lesley, who will bring with her new skills and perspectives from her previous research.

Currently, Lesley is a postdoctoral scholar at  the National Center for Ecological Analysis and Synthesis (NCEAS) in Santa Barbara (California, USA), where she has been since 2009. Her main focus of research has been to reconstruct historical evolutionary processes of adaptation, speciation, extinction and migration using time-calibrated molecular phylogenies of various Californian plant clades. She is also interested in historical habitat tolerances of the unique California chaparral habitat. Her postdoctoral research has resulted in some interesting papers in BMC Evolutionary Biology and Systematic Biology.

Lesley's thesis research was on a quite different topic: maternal effects, reproductive strategies and evolutionary ecology of a colour polymorphic lizard (Uta stansburiana), where she worked in the laboratory of Barry Sinervo at University of California, Santa Cruz (UCSC). Her thesis work also resulted in a number of interesting and impressive publications in American Naturalist, Ecology Letters, Evolution and PNAS. 

Lesley is thus an extremely broad and well-rounded biologist and a very experienced postdoc, who has worked at quite different levels of biological organization, and moved her research focus from studies of individual behaviour and evolutionary ecology, to broader macroevolutionary and macroecological questions. It is for precisely these reasons we are excited to bring her in to Lund; she has both sufficient much in common with our already ongoing research,  yet has many complementary skills that will be of interest to us and our research.