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 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?
During the spring, we started field work in California’s salt marshes and began collecting the diversity of trematode species needed for this research. In summer, we designed our behavioral experiments and began witnessing where interspecific aggression occurred in these trematode communities. This fall, we will improve our behavioral experiments by creating (and testing) nutritional mediums to sustain in vitro trematode interactions longer, and attempt to answer these preliminary questions: (1) which trematode species are capable of within-species aggression, and (2) if a trematode colony is separated for some time, and then rejoined, do they still recognize each other as colony mates, or do they treat each other as strangers? These fundamental questions of colony interactions have been asked and answered in social insects, so answering these questions for trematodes will begin to show the similarities and differences in social evolution across trematodes and the more well-known social animals. Finally, beyond social evolution interests, studying trematode aggression to this depth will reveal the mechanisms by which competitive trematode communities have achieved their composition and coexistence 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, set up behavioral assays, and possibly extract and analyze DNA and proteins from trematodes.
These are the tasks both myself and the student will be doing, but snail dissecting, trematode identification, and setting up 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/or genetic analysis, this project is most beneficial for a student experienced and deeply interested in animal behavior; seeking to learn the methodology for figuring out what an animal is doing, why it is doing it, and how it got that way.