Diet and Spatial Pattern of Foraging in Ectatomma opaciventre ...

616 Sociobiology Vol. 58, No. 3, 2011
periods than closer areas. This would explain the higher number of individual
foraging pathways of E. opaciventre closer to the nest.
Therefore, foraging strategies seem to depend upon several ecological
variables, such as the distribution of food resources in time and space, food
size and quality, competition, and predation. A colony must then have a spatial
pattern of foraging to collect food effectively and minimize the chance
of competition, in order to assure less energy waste and a greater input of
resources in the shortest time.
CONCLUSION
The diversity of prey collected by E. opaciventre in the area studied was
low, most probably because of the poor variety of species in the degraded
environment and because the observations were carried out in the dry season.
Collecting other ant species as the major part of its diet was likely due to the
abundance and high richness of individuals belonging to several subfamilies of
Formicidae in the area studied. The foraging trails of E. opaciventre presented
a pattern similar to those observed in other Ectatomminae studied. With a
sinuous profile and directional fidelity, these trails avoid competition with
other nests and lead to a better division of the resources explored. Although
most trips were unsuccessful, the foragers did not stray too far from the nest,
nor did they spend too much time foraging. Since the area was dominated by
grass, intense sunlight and heat was present, which could have caused the ants
physical exhaustion if they had extended the time spent outside the nest.
ACKNOWLEDGMENTS
We thank the National Council for Scientific and Technological Development
(CNPq) for the financial support.
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