Zoom Link: https://binghamton.zoom.us/j/98942256738
Throughout the history of life lower-level units have become associated into higher levels of organization—prokaryotic into eukaryotic cells, cells into multicellular organisms, and individuals into social groups. Cooperative breeding spiders and related less-social species illustrate how group living and cooperation may arise as solutions to environmental challenges that solitary-living species of certain characteristics cannot meet. Spider species that build costly three-dimensional webs, for instance, may be excluded from areas with strong disturbance by rain or predators unless they live in groups. In addition to communally maintaining their webs and caring for their offspring, these spiders cooperate in the capture of insects many times their body size. As large insects are required for large colonies to form, colonies with up to thousands of individuals form in some areas of the world and not in others. After reviewing the research that led to uncovering the drivers of group living in these organisms, I will consider the conditions under which natural selection at the level of the collective may overcome selection on the individual units to favour traits ranging from cooperation to female-biased sex ratios. In doing so, I will consider the full spectrum of population structures, from short-lived groups of non-relatives that form by aggregation, as in the cellular slime molds or many human institutions, to groups that grow through internal recruitment over the generations, as in the social spiders.
Leticia Avilés is full professor at the Department of Zoology and the Biodiversity Research Centre at the University of British Columbia (UBC), in Vancouver, Canada. With an emphasis on group-living arthropods, her research seeks to elucidate the forces responsible for the origin of higher levels of organization and the consequences of such origins on the structure and dynamics of populations. She earned her PhD at Harvard University and was a post-doctoral fellow and then assistant and associate professor at the University of Arizona (UofA) before joining UBC in 2002. Work in her lab uses both empirical and theoretical approaches to explore the drivers and selective forces involved in the formation of social groups. She has published over 80 papers and book chapters and trained graduate and undergrad students and post docs at three institutions (UBC, UofA, and the Pontificia Universidad Católica del Ecuador, in Quito, where she initiated her training as a biologist). She has received funding from NSF, NSERC, and the James S. MacDonnell Foundation and is a recipient of the American Society of Naturalists Young Investigator Award, a fellow of the Institute for Advanced Studies in Berlin and of the Animal Behaviour Society. She will be joining the board of the American Naturalist as the Natural History Editor in March 2023.
Aviles, L. 2020. Social Spiders. In Starr, C.K., Ed., Encyclopedia of Social Insects. Springer, Cham. doi.org/10.1007/978-3-319-90306-4_110-1. Link: https://doi.org/10.1007/978-3-030-28102-1_110
Avilés, L. 2002. Solving the freeloaders paradox: Genetic associations and frequency dependent selection in the evolution of cooperation among nonrelatives. Proceedings of the National Academy of Sciences of the USA 99(22): 14268-14273. Link: https://doi.org/10.1073/pnas.212408299