Evolution 2018

This coming August, the Joint Congress on Evolutionary Biology (a.k.a Evolution 2018) is right here in France! This is a joint meeting of the European Society for Evolutionary Biology, American Society of Naturalists, Society of Systematic Biologists, and Society for the Study of Evolution. It is generally, but not always, held in the U.S., so it's quite nice to have it practically in our backyard this coming year. The proposal for my current fellowship included specifics about what meetings I would attend to present our findings. I was excited at the time, way back in September 2016, to see that this meeting would be so close by! I’ve never attended the Evolution meetings before, so it will be a great opportunity to meet new people, gain some different perspectives, and hear about some great research that’s well outside my area (for example, advances in social evolution or phylogenetics).

Already the meeting has had an influence on my work. As I began writing the abstract for the talk I hope to give, it occurred to me that I have been thinking primarily as an eco-physiologist more than as an evolutionary biologist. For example, the Colloque d'ÉcoPhysiologie Animale I attended in November was specifically focused on ecophysiology (as you might guess from the name). Thus, my presentation was largely of an eco-physiology mindset to primarily ecophysiologists. Which is not a bad thing, of course (from my experience, ecophysiologists tend to be quite friendly) – it’s just to say that stepping back and thinking more broadly, or differently, is always a good thing.

Of course, evolutionary thinking undermines all my research (after all, in the famous words of Theodosius Dobzhansky, “Nothing in biology makes sense except in the light of evolution”). I just hadn’t been thinking about evolutionary processes explicitly. Fortunately, my advisor Fabien Aubret here at the SETE is very much an evolutionary biologist and has helped me be more explicit in thinking about the evolutionary implications of our work. For example, our experiment this spring will continue our work on thermal ecology and hypoxia tolerance, but with a specific focus on local adaptation and the potential heritability of these traits. With this in mind, I think I was able to hone my thinking a bit and put together an abstract combining our past, ongoing, and future work: including the Cordero et al. study on egg incubation now out in the Journal of Experimental Zoology, our ongoing experiment with male lizards, and the experiment we have planned for this coming year.

Below is a draft of the abstract I submitted – with hopes that I’ll be selected to give an oral presentation. Montpellier, here we come!

Physiological plasticity in response to high-altitude hypoxia and the evolutionary potential for upward range expansion in the Common Wall Lizard

Eric J. Gangloff¹, Mahaut Sorlin¹, G. Antonio Cordero², Jérémie Souchet¹, Fabien Aubret^1 
1Station d’Ecologie Théorique et Expérimentale du CNRS, ²Universität Tübingen

Formerly inhospitable habitats at high elevations have warmed to become thermally suitable for some low-altitude species. However, the extent to which reductions in oxygen availability interact with temperature to limit colonization of novel high-altitude environments is not clear, particularly in ectotherms. Here, we combine classical physiological measures and quantitative genetic approaches to assess the potential for upward migration of the Common Wall Lizard (Podarcis muralis). With lizards from the Pyrénées Mountains of southern France, we first found that physiological adjustments, including those related to cardiorespiratory capacity and metabolic rate, facilitate the development of embryos in high-altitude hypoxia. Second, we found that despite within-individual physiological plasticity in traits related to oxygen delivery and consumption, including blood chemistry and maximum metabolic rates, adult lizards are not able to maintain ecologically-relevant performance traits (sprint speed and running endurance). Next, we assessed variation in physiological traits and their relative plasticity in female lizards and their offspring from populations across an altitudinal gradient, including the local altitudinal range limit. This included a test of whether gestating moms exposed to high-altitude hypoxia could prepare their offspring for future life in this environment. By integrating measures of physiological variation and plasticity potential at multiple life-history stages from populations across elevations, we quantify the relative roles of standing phenotypic variation, within-individual plasticity, and evolutionary potential to facilitate colonization of high-elevation sites. Finally, we apply these results in mechanistic models to forecast how populations of ectothermic species respond to environments that become suitable along one niche axis (temperature) but remain novel on others (hypoxia).