Autor: |
McEwen, Brendan L., Lichtenstein, James L. L., Fisher, David N., Wright, Colin M., Chism, Greg T., Pinter-Wollman, Noa, Pruitt, Jonathan N. |
Předmět: |
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Zdroj: |
Behavioral Ecology & Sociobiology; Jan2020, Vol. 74 Issue 1, p1-9, 9p |
Abstrakt: |
Many animal societies are susceptible to mass mortality events and collapse. Elucidating how environmental pressures determine patterns of collapse is important for understanding how such societies function and evolve. Using the social spider Stegodyphus dumicola, we investigated the environmental drivers of colony extinction along two precipitation gradients across southern Africa, using the Namib and Kalahari deserts versus wetter savanna habitats to the north and east. We deployed experimental colonies (n = 242) along two ~ 800-km transects and returned to assess colony success in the field after 2 months. Specifically, we noted colony extinction events after the 2-month duration and collected environmental data on the correlates of those extinction events (e.g., evidence of ant attacks, no. of prey captured). We found that colony extinction events at desert sites were more frequently associated with attacks by predatory ants as compared with savanna sites, while colony extinctions in wetter savannas sites were more tightly associated with fungal outbreaks. Our findings support the hypothesis that environments vary in the selection pressures that they impose on social organisms, which may explain why different social phenotypes are often favored in each habitat. Significance statement: Many social animals are susceptible to group extinction events. Identifying the factors that precipitate these events can help us to understand how societies function and evolve. We used a social spider model to evaluate whether the drivers of group extinction events may vary with habitat type. We found that ant attacks were more commonly associated with colony demise at arid sites, whereas fungal outbreaks were associated with collapse in wetter environments. If maintained temporally, these contrasting selection pressures could facilitate the evolution of local adaptation in individual- and colony-level phenotypes and aid in the maintenance of intraspecific trait diversity. [ABSTRACT FROM AUTHOR] |
Databáze: |
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