How temperature influences displacements and corpse aggregation behaviors in the ant Messor sancta

We studied the effects of temperature on movement and individual corpse aggregation behaviors (picking up or dropping a corpse) in the ant Messor sancta. Dispersion of ants in space was higher at 30 degrees C than at 16 degrees C. Concerning aggregation behaviors, we observed at both temperatures that the probability of picking up a corpse from a pile was negatively correlated with pile size, while the probability of dropping a corpse was positively correlated with pile size. The combined picking up and dropping behaviors represent a local amplification of corpse aggregation that is stronger at 30 degrees C than at 16 degrees C. Overall, this study shows clearly that the transport of corpses by ants, as well as the amplification process involved in corpse aggregation, is modulated by temperature. The implications of these results on the dynamics of ant cemetery formation (and other aggregation behaviors) are discussed. We propose that the modulation of a local amplification process by an environmental factor could be a general mechanism involved in the coordination of ant activity to adapt the external and internal shape and organization of the nest to environmental conditions.