Meeting Abstract

P1.64  Tuesday, Jan. 4  Plasticity in resource allocation in new harvester ant colonies APPLEBY, Lara; Univ. of Houston lrappleby@uh.edu

Ant worker size varies during colony development in ways that may be adaptive. Colonies of many ant species initially produce small workers (nanitics). The disadvantages of nanitics’ small size are thought to be outweighed in beginning colonies by the immediate advantage nanitics confer in colony growth and perhaps therefore also in colony survival. How new queens allocate resources among offspring size, offspring number, and self-maintenance is unknown. I test the hypothesis that colony resource allocation strategies maximize growth rate of beginning colonies (“fast-start”). This hypothesis predicts that new queens which are provided with more resources will produce more offspring rather than larger offspring and lose less personal mass during colony founding. Queen production of larger offspring in response to food supplementation would instead suggest that colony resource allocation strategy has been set by selection at the mature colony stage, resulting in suboptimal immediate responses of colony growth rates to resource supplementation (“lifestage-discord”). I treated each of 8 groups of 20 new harvester ant queens to a unique combination of temperature (26°C, 30°C), food (protein-limited, unlimited), and brood-caretakers (0 foreign conspecific pupae, 8 pupae). As predicted by the fast-start hypothesis, colonies with more food or caretakers made more, rather than larger workers and queens in those two treatments lost less mass during worker production. Workers made by colonies with more caretakers were also larger, in line with the lifestage-discord hypothesis. Protein-limited colonies also made larger workers. I present theories of intracolonial food-dynamics that account for these conflicting results. Overall, the results support the hypothesis that the resource allocations strategy that causes early colonies to produce nanitics is an adaptation for early colony life.