Cognition and Natural Selection

I took advantage of the recent species radiation of sticklebacks in British Columbia to study cognitive evolution in a comparative framework. Limnetic and benthic stickleback fish differ in their feeding habits, sociality, habitat complexity, body size, shape, antipredator defenses, mating traits, and dependence on vision vs. olfaction, suggesting differences in cognitive abilities and neuroanatomical structures might exist. Selection is strongly implicated when consistent differences between limnetic and benthic fish are demonstrated across lakes. I used two very different, but complementary approaches:

First, I conducted behavioral experiments in Jenny Boughman's lab at Michigan State University to assess specific cognitive abilities in each species. As one example, I quantified social information use, specifically the ability to use the feeding behavior of others to locate a food patch. This work involved undergrads Whitley Lehto, Ross Minter, Ashley Baird, Sarah LoPresto, and Ashley Lindo. As another example, I and undergrad Jonatan Martinez quantified the relative role of genes and environment in producing species differences in spatial learning (with lots of help from undergrads Benjamin Wurst and William Fetzner). That work was published in Evolutionary Ecology Research [pdf]. I am also developing an automated operant conditioning device for large-scale quantification of discrimination and reversal learning (a project that involved undergrads Clayton Batko, Peter Vites, and William Fetzner at MSU and currently involves Jake Ritthamel at the University of Illinois).

Second, I collected neuroanatomical data on specific brain structures using magnetic resonance imaging (MRI). This work was a collaboration between myself and Jenny Boughman at Michigan State University and Victoria Braithwaite and Thomas Neuberger at Penn State University, with help from undergrad Katelyn Doolittle. That work was published in a Special Column in Current Zoology, “Ecology and Evolution along Environmental Gradients” [open access link].

Social information use experiment: delayed local enhancement

spatial learning

Spatial learning setup.

Stickleback MRI

Images from MRI. (a) Limnetic fish, sagittal section. (b) Benthic fish, sagittal section.