90.5 Friday, Jan. 6 Resource availability and colony founding in harvester ants APPLEBY, L.R.; Univ. of Houston firstname.lastname@example.org
In many organisms, the riskiest life stage is the beginning. Some species deal with this by producing well-provisioned individuals who do not need to forage for some time. In harvester ants of the genus Pogonomyrmex, the highest mortality rates are at the beginning of colony life, when queens start colonies without workers. Some species like P. barbatus start colonies claustrally, without foraging, while others like some populations of P. occidentalis, regularly gather food while first brood develops (semi-claustral founding). It is thought that species have adapted their colony founding strategies to the resource availability of their native habitats. I hypothesized that a normally claustral queen would be handicapped relative to queens of a naturally semi-claustral species in use of exogenous food. I fed newly mated barbatus and occidentalis queens no food, low food, or high food and measured the queen’s mass lost during production of the first clutch, the size of the first clutch, and the size of the first worker. In both species, unfed queens lost the most mass. In the claustral species, fed queens lost more mass when they were fed less (low food) rather than more (high food). Fed semi-claustral queens, on the other hand, lost equal mass regardless of the level of food provided. Food availability did not affect offspring size or clutch size in the claustral species, but the semi-claustral species produced larger offspring and clutches when exogenous food was provided. Low and high food queens of both species produced similar sized clutches and first workers. In conclusion, both claustral and semi-claustral queens can use exogenous food to maintain themselves during colony founding, but semi-claustral queens may be better than claustral queens at using exogenous food.