Abstract
Individuals vary within a species in many ecologically important ways, but the causes and consequences of such variation are often poorly understood. Foraging behavior is among the most profitable and risky activities in which organisms engage and is expected to be under strong selection. Among social insects there is evidence that within-colony variation in traits such as foraging behavior can increase colony fitness, but variation between colonies and the potential consequences of such variation are poorly documented. In this study, we tested natural populations of the red imported fire ant, Solenopsis invicta, for the existence of colony and regional variation in foraging behavior and tested the persistence of this variation over time and across foraging habitats. We also reared single-lineage colonies in standardized environments to explore the contribution of colony lineage. Fire ants from natural populations exhibited significant and persistent colony and regional-level variation in foraging behaviors such as extra-nest activity, exploration, and discovery of and recruitment to resources. Moreover, colony-level variation in extra-nest activity was significantly correlated with colony growth, suggesting that this variation has fitness consequences. Lineage of the colony had a significant effect on extra-nest activity and exploratory activity and explained approximately half of the variation observed in foraging behaviors, suggesting a heritable component to colony-level variation in behavior.
Highlights
Individuals vary within populations in many ecologically important ways [1,2,3,4] and there is mounting evidence that this variation can have large effects on populations and communities [5,6,7]
We selected collection sites in Texas and Mississippi because in previous field work we observed differences in the arboreal and ground-level foraging behavior of fire ants from the two regions [36]. This is of particular interest because differences in the use of arboreal resources have been linked to the invasive success of fire ants in the United States and the ecological dominance of multiple ant species [37,38,39,40,41]
The results of this study suggest that natural populations of fire ants exhibit substantial colonylevel variation in foraging behavior both among and within populations, that this variation persists over time and across environments, and that this variation can have significant consequences for colony performance
Summary
Individuals vary within populations in many ecologically important ways [1,2,3,4] and there is mounting evidence that this variation can have large effects on populations and communities [5,6,7]. Social insects are often abundant and provide critically
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