Foraging behaviour and ecology of the ant Dinoponera australis

HOLIK, F.; HANISCH, P; SUAREZ, A.; TUBARO, P. L.

Buenos Aires

Congreso; I Reunión de Biología del Comportamiento del Cono Sur. Comporta 2017 - VI JUCA.; 2017

Facultad de Ciencias Exactas y Naturales, UBA

In Iguazú National Park, D. australis colonies are over-dispersed and the species reach a wet biomass of more than 2.5 kg/ha, a biomass comparable with small vertebrates in tropical forest. Data obtained from stable isotopes and from direct observations of foraging success in Iguazú, suggest that these ants are among the top predators in this terrestrial invertebrate community. Moreover, workers exhibit relatively high degrees of route fidelity. Their big size, the fact that workers search for food individually without nest-mate recruitment, and their relatively small number of active foragers makes them a useful model to study individual and nest foraging strategies. We tested the hypothesis that each ant specialized in a particular area around the nest. Additionally, we surveyed other relevant variables (duration of the foraging trips, foraging success, maximal distance to the nest, etc). To achieve our goals, detailed foraging routes were mapped for individually marked workers with the help of an X/Y coordinate system placed in the foraging area around the nest. We also excavated half of the studied colonies. We obtained 121 individual foraging routes from 6 nests. The total area used by each colony average 42m2, foraging time average 24 minutes (range 1 - 176 minutes) and the probability of encounter food was 31%.We studied the possibility of applying the Maximum Entropy principle to describe the statistics of foraging parameters. Together, these data provide insight into the biology of one of the world?s largest ants and why they may be able to attain such high densities.