Eco-Evo Evo-Eco

Second day of the CSEE conference and more exciting insides into eco-evolutionary research from all over the world and all over the place. Our morning sessions covered mainly ecological topics: One could learn how the distribution of plant populations can be inferred by tracking pollen (Parker et al.: The needle in the haystack: tracking pollen distributions to locate important plant populations), and how population dynamics in small rodents can be inferred by tracking regurgitates (Heisler et al.: Picking up puke: A method to monitor small mammal communities across landscapes) – quite a spectrum! Regarding anthropogenic impacts on species and ecosystems, an interesting study from Lobo et al. presented evidence for increased aggression and social dominance in rodent populations from recently logged forest habitats. Vincent Fugere presented a meta-analyses of selection coefficients imposed by humans. Vincent found that, contrary to the expectation, selection was reduced in many anthropogenic contexts, including habitat disturbance and logging (Fugere and Hendry: Human influences on the strength and shape of phenotypic selection). This is somewhat paradoxical since many other studies found for e.g. strongly elevated evolutionary rates in anthropogenic contexts (see e.g. Hendry and Kinnison 1999 and follow up studies and meta-analyses).

On the other side of the hall, in the “ecology and evolution” section, Rana El-Sawaabi (et al.) presented her preliminary results from sticklebacks linking eco-evo dynamics through the “elemental phenotype”: while phosphorous concentration on stickleback’s body correlates with the degree to which they express the armored phenotype, they find the surprising result that more armored individuals are also the ones that excrete more phosphorous to the environment. Their next goal is to determine to what extent phosphorous availability constrains the development of armor in freshwater (a trait that is often interpreted to respond to predation pressure). This is interesting research in the context of eutrophication and cascading ecosystem effects. Stay tuned!

Two afternoon highlights were the talks by Em Standen (et al.) and Felipe Dargent (et al.) – both concerned to look at evolutionary dynamics by manipulating environments of focal organisms, in this case (of course) fish:

A while ago, Em decided to start raising fish on land to see what happens.. sounds interesting? Yes, it is. Standen et al. chose Polypterus as their model species as this creature seems to be determined (well, at least morphologically) to fill at least some of our gaps in knowledge about the conquest of land by vertebrates. By raising Polypterus in artificial lab environments that forced them to make a living outside of the water, these fish explored an immense repertoire of behavioral and anatomical plasticity, enabling them to move effectively on land surfaces (well, at least for a fish that is). Very cool stuff!

Felipe, on the other hand, decided a while ago to study guppies from different populations and parasitation regimes in the context of what he calls “enemy release”, i.e. under relaxed parasite pressure, to track down changes in resistance evolution. Dargent et al. elegantly showed that under relaxed selection (removal of the parasite in the wild) male and female guppies rapidly evolve different trajectories of resistance. While females, as they showed before, evolve increased resistance after parasite removal, males increase their variance in resistance but do not evolve increased (or decreased) resistance. Since their replicated parasite-released populations were derived from an ancestral population that was sexually dimorphic in resistance (males more resistant than females) the evolution seen in females but not males has led to an evolutionary loss of sexual dimorphism – within 6-8 generations!

So far for a brief Tuesday's summary.. back to the lecture halls!