Ecological correlates and community-wide consequences of spider sociality

• Main Author: Guevara, Jennifer Carlota
• Language: English
• Published: University of British Columbia 2012
• Online Access: http://hdl.handle.net/2429/43630

Understanding the suite of ecological conditions that favor sociality —the tendency of organisms to form groups and cooperate— is key to understanding the origin, maintenance and contribution of social groups to biodiversity. The ecological dynamics of sociality can in turn have many consequences that feed back to influence the way species use the available resources, interact with other species, and persist in nature. The causes and consequences of sociality thus arise from the interplay of organisms and ecological processes. My thesis includes three studies that provide insight into some of the ecological processes that influence sociality and in turn the consequences that sociality may have in resource use and community structure. In the first study (Chapter 2), I use ecological niche modeling to predict the geographical distribution of social and subsocial New World Anelosimus spiders and explore their ecological correlates across latitude and elevation. Using a comparative approach, I further show that elevational patterns are strongly associated with differences in climatic conditions between social systems. In the next study (Chapter 3), I explore the role of group living and cooperation in resource use in a natural community of Anelosimus spiders of similar body size, but with behaviors ranging from near-solitary to fully social. I conduct surveys of prey capture in four sympatric Anelosimus species in Brazil and find that level of sociality and cooperation greatly shape resource use and act to separate different species into different ecological niches. Finally, I conduct feeding experiments to analyze in more detail the emergent patterns of resource use in two sympatric spiders with similar level of sociality but different body size (Chapter 4). I find that differences in resource use arise through differences in foraging efficiency emerging from the interplay of sociality and individual traits (e.g. body size). My thesis highlights the importance of ecological processes in the broad-scale spatial distribution of sociality and its potential consequences in resource use, community structure and ultimately the maintenance of local diversity. These studies also emphasize the work that remains to be done in such exciting area of research.