PARENT SESSION
Poster Session # 1: Ecological Theory and Evolutionary Ecology.
Monday, August 4 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.
Ant Energetics—The scaling of foraging costs with colony size.
Moses, Melanie*,1, Lease, Hilary*,1, 1 University of New Mexico, Albuquerque, NM, USA
ABSTRACT- Ant colonies have population sizes ranging from tens to millions. The ant genus Pogonomyrmex contains species with maximum population sizes ranging from 100 to 10,000 individuals per colony. We examine what factors might generate these extreme differences in colony size. We investigate how the energetic cost of foraging scales with colony size in these seed harvesting desert ants. The energetic cost of foraging is the distance foraged times the metabolic expense per distance. Ants in larger colonies travel greater distances to obtain sufficient food for the colony. However, the cost incurred by traveling longer distances must somehow be compensated for in large colonies. Here, we test the hypothesis that increased metabolic efficiency (per ant, per distance traveled) also occurs in larger colonies. We make field observations of forager population size and foraging distance, and laboratory measurements of oxygen consumption and ant mass to assess the metabolic cost of foraging in colonies of different sizes. We use this data to construct a metabolic argument to explain why species can exist at radically different colony sizes.
Key words: energetics, colony size, scaling, ant