Submitted by Neil Tsutsui on
The most impressive product of social evolution is the eusocial society: a group of animals with a division of labor, cooperative brood care, and nest-living with overlapping generations. The classic examples are social insects (ants, bees, wasps, and termites) but this list has expanded to include humans, shrimp colonies, naked mole rats, and most recently: trematodes. Trematodes are parasitic flatworms, common parasites of snails, where some species form larval infrapopulations with a division of labor. “Reproductives” are large and asexually produce larvae, while “soldiers” are small and attack enemy trematodes trying to establish in the same snail. That is the extent of our knowledge on trematode sociality, so with this research we seek to answer one of the most fundamental questions one can ask about their sociality: how do these trematodes recognize their in-group from their out-group? What separates friend from foe?
Having started this project in the spring semester, we are continuing work into the summer, incorporating a new branch of our project requiring more long-distance field work and the introduction of genetic analysis. With behavioral assays underway revealing who the trematodes will fight and why, we now want to know if their aggressiveness towards outsiders is better explained by geographic distance or genetic distance. This can help us hone in on what their recognition cue is and where it originates from (their environment or their genes). Describing the influence of geography and genes on a trematode’s recognition of enemies will begin to show the similarities and differences in social evolution across flatworms and the more well-known social animals (mammals, insects, etc.). Finally, studying trematode aggression from samples across California for this summer project will begin establishing a range-wide database of how trematode community competition is uniquely expressed in marsh ecosystems across California.
Field work = travel to salt marshes across California, develop search image of California horn snails and their habitat, collect snails, and learn basic salt marsh ecology
Lab work = dissect snails, identify and preserve trematodes, perform behavioral assays, and extract and analyze DNA.
These are the tasks both myself and the student will be doing, but once the project gets on its way, the field collecting, snail dissecting, and trematode identification and behavioral assays will probably make up the majority of the undergraduate’s work.
Independent, enthusiastic, and experienced. While good experiences include field work in marshes, and/or lab work with chemical ecology and genetic analysis, this project is most beneficial for a student experienced and deeply interested in animal behavior; to wield the methodology for figuring out what an animal is doing, why it is doing it, and how it got that way.