Social Resilience and Behavioral Flexibility in Major Workers of the Ant Pheidole dentata

Meeting Abstract

P3-116  Saturday, Jan. 7 15:30 – 17:30  Social Resilience and Behavioral Flexibility in Major Workers of the Ant Pheidole dentata POOLE, AM*; MUSCEDERE, ML; Hendrix College, Conway AR; Hendrix College, Conway AR

Polymorphism in social insect workers is often assumed to enhance division of labor but limit colony resilience in the face of environmental or social perturbations, since morphologically specialized worker subcastes (e.g. large major workers) general have specialized behavioral repertoires (e.g. defense). We investigated the ability of P. dentata majors to display behavioral plasticity when challenged with a task typically performed by their smaller minor nestmates (brood care), and tested a possible neuromechanism, biogenic amine signaling, that could influence task performance. We asked: (1) How does the performance and quality of brood care vary over one week in colonies where the proportion of major workers is higher than typical (ca. 10%); (2) are there costs to any behavioral compensation shown by workers in colonies with disrupted subcaste ratios; and (3) is plasticity of biogenic amine signaling a mechanism underlying behavioral compensation? Our results indicate that while brood condition suffered initially in colonies comprised entirely of majors, these majors largely compensated for the lack of minor worker efforts within 4-6 days by increasing their rates of foraging and brood-directed behaviors. Brood outcomes and foraging rates in colonies comprised of 80% majors were intermediate between 100% and 10% major colonies. While the time delay associated with behavioral plasticity in 100% major colonies is consistent with underlying physiological regulation, amine signaling did not appear to be strongly linked to our social perturbations. Our findings suggest that the ability of P. dentata major workers to flexibly contribute to brood care may be underestimated, and could buffer colonies from the potential costs of morphological specialization when caste ratios are disturbed.

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