| Description |
Ants are social organisms, likely a key behavior explaining their high ecological success. Among the benefits are enhanced foraging opportunities, group defense, and living inside nests, which help ameliorate environmental extremes. Yet sociality brings new challenges, among them a sessile life. In this dissertation I studied two crucial aspects of ants that likely evolved as a response to their sessile nature. One aspect is understanding the costs and benefits of nest relocation. To address this question, I studied the behavior of the ant Pheidole dentata, which is a common species of the American southeast. I found that colonies relocated often, on average every 16 days. Colonies used a variety of nest types, such as the ground, tree trunks, and under rocks. Colonies nesting in the ground were the most likely to relocate compared to other locations. Leaf-litter depth and vapor pressure deficit also increased the likelihood of colonies relocating. There were also spatial and temporal variations in relocation rates. Thus, relocation is affected by various abiotic conditions affecting colonies simultaneously. Ant nests also gave colonies a tempered environment compared to external temperature conditions. Internal nest temperatures fluctuated much less than air temperatures, and these were on average lower than external ones. Colonies appear to choose locations that remain cooler than adjacent locations. They also avoid places where temperatures will exceed 38°C, possibly because scouts are unable to forage at those temperatures. Thus, colonies appear to have some thermoregulatory control through relocation. A second behavior that I studied is resource discovery in ants, as the ability to find resources is crucial to their survival. In general, more ants searching for food meant faster discovery, either at the community level or at the species level. Nevertheless, the efficiency of scouts finding food differed by species. Thus, scouts of some species were able to find food faster than foragers of other species. These results highlight that discovery in ant communities depends on both the number of ants searching for food, and the individual abilities of workers at locating resources. |
