Intraspecific behavioral variation and the red imported fire ant foraging gene

Among social insects, genetic variation in a behavior can allow a colony to exhibit more flexible, rapid responses to environmental changes and promote homeostasis. Such variation enables adaptive evolution and can increase colony fitness in multilineage colonies such as polygynous red imported fire ants (Solenopsis invicta). Our preliminary research demonstrated significant and persistent colony-level variation in fire ant foraging behavior. In a some social insects, variation in foraging behaviors and division of labor has been associated with variation in expression of the foraging gene (for). We assayed foraging behavior and for expression of field colonies and single-lineage laboratory colonies reared in standardized environments. Colony lineage explained about half of all variation observed in foraging-related behaviors. Fire ants varied in for expression at the task level and  increased for  expression correlated with increased foraging.  This study suggests that significant genetic variation in foraging behavior exists among fire ant colonies and may underlie variation in the ecological effects of fire ants and variation in methods necessary for their control.