Como a temperatura influencia a eficiência do forrageamento de Atta laevigata (Hymenoptera: Formicidae)

Abstract

The foraging dynamics of leaf-cutting ants varies according to temperature, but this is little known for Atta laevigata, one of the most important pest in Brazil. The objective of this work was to evaluate the foraging efficiency of the A. laevigata colony in relation to temperature variation, under laboratory conditions. Three sub-colonies were connected, by a transparent hose, to a foraging arena inside a BOD with a temperature of 10°, 22° and 40°C, simulating the external environment. A video camera was installed above the exit of the foraging arena, to record the foraging of ants during 12 hours, with five replications per sub-colony and temperature. The number of workers with and without load per minute (ants/minute) in both directions, head capsule size of the recruited workers, walking speed of the ants and mass of transported material were measured, by temperature and sub-colony. Data analyzes were carried out with GLM modeling using the R statistical software. The flow of workers on the trail, weight of fragments transported by the ants and walking speed of A. laevigata workers were higher at the optimal foraging temperature (22ºC), however, the size of recruited workers did not vary with temperature. Colony foraging efficiency was higher at 22oC and reduced at extreme temperatures. Changes in the behavior of A. laevigata foragers as a function of temperature variation indicate behavioral flexibility allowing foraging and maintenance of resources even under extreme conditions. The results are important to understand the ecology and improve the management of this species. Keywords: Leaf-cutting ants, abiotic factors, ant flow, behavior.