Evidence for contrasting size-frequency distributions of workers patrolling vegetation vs. the ground in the polymorphic African ant Anoplolepis custodiens

Abstract

It is often hypothesized that ant species with substantial variation in worker body size should have schemes for allocating workers to different foraging tasks based on size. Here, we document in Anoplolepis custodiens ants preliminary evidence for a relationship between worker body size and the foraging surfaces on which workers walk. Workers of A. custodiens were collected in pitfall traps near their nest entrances and compared in size to workers exploring the branches of associated shrubs (Salsola sp.). Although ants of all sizes moved freely on the ground, the bushes were almost entirely populated by the smallest workers. These results suggest an effect of substrate on the foraging behavior of an understudied species and suggest that A. custodiens might be a good model to explore size-based behavioral differences in polymorphic ants.