title: The cost of being queen: investment across Pogonomyrmex harvester ant gynes that differ in degree of claustrality.
abstract: The role of the ant colony largely consists of non-reproductive tasks, such as foraging, tending brood, and defense. However, workers are vitally linked to reproduction through their provisioning of sexual offspring, which are produced annually to mate and initiate new colonies. Gynes (future queens) have size-associated variation in colony founding strategy (claustrality), with each strategy requiring different energetic investments from their natal colony. We compared the per capita production cost required for semi-claustral, facultative, and claustral gynes across four species of Pogonomyrmex harvester ants. We found that the claustral founding strategy is markedly expensive, costing approximately 70% more energy than that of the semi-claustral strategy. Relative to males, claustral gynes also had the largest differential investment and smallest size variation. We applied these investment costs to a model by Brown and Bonhoeffer (2003) that predicts founding strategy based on investment cost and foraging survivorship. The model predicts that non-claustral foundresses must survive the foraging period with a probability of 30-36% in order for a foraging strategy to be selectively favored. These results highlight the importance of incorporating resource investment at the colony level when investigating the evolution of colony founding strategies in ants.
authors.affiliation: Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 621 Charles E. Young Drive South, Box 951606, Los Angeles, CA 90095, USA. Electronic address: benzmann@gmail.com.
authors.forename: Brittany L
authors.initials: BL
authors.lastname: Enzmann
authors.affiliation: School of Life Sciences, University of Nevada, Las Vegas 4505 S. Maryland Pkwy., Las Vegas, NV 89154, USA. Electronic address: allen.gibbs@unlv.edu.
authors.forename: Allen G
authors.initials: AG
authors.lastname: Gibbs
authors.affiliation: Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 621 Charles E. Young Drive South, Box 951606, Los Angeles, CA 90095, USA. Electronic address: pnonacs@biology.ucla.edu.
authors.forename: Peter
authors.initials: P
authors.lastname: Nonacs
mesh_terms: D000818:Animals; D001000:Ants / Q000502:physiology*; D001481:Basal Metabolism / Q000502:physiology; D004734:Energy Metabolism / Q000502:physiology; D005260:Female; D008297:Male; D012098:Reproduction / Q000502:physiology; D012919:Social Behavior
keywords: Claustral; Colony founding; Harvester ant; Parental investment; Pogonomyrmex; Semi-claustral