​The Genetic Basis of Rescue Behavior in Tetramorium caespitum​​​


A defining characteristic of eusocial insect species is division of labor. Castes as well as task specialization are genetically influenced in many eusocial species, though environmental cues and other factors also play a role. One intriguing task specialization that may function to enhance the survival of the colony is rescue behavior, where individual ants place themselves at risk in the process of aiding a trapped nestmate. The common pavement ant Tetramorium caespitum exhibits this behavior; however, the mechanism underlying this task specialization is not known. The present project aims to test two hypotheses: first, that rescue behavior is genetically influenced in T. caespitum. Other common tasks are genetically influenced, such as foraging, so it is possible that rescue behavior is similarly genetically coded. Second, we hypothesize that T. caespitum are more likely to rescue individuals to which they are more closely related. Behavioral assays were conducted to quantify rescue behavior and individuals showed different propensities to rescue victims. Genetic analyses were used to determine relatedness between individuals and infer paternity. If the hypotheses are true, we expect that the propensity to engage in rescue behavior will be correlated with genetic relatedness and that rescuers are more closely related to victims than non-rescuers in the same behavioral trials.