The influence of colony traits on the collective behaviour of Myrmica scabrinodis ants

Eusocial insects exhibit different kinds of collective behaviours which are the outcomes of interactions among several individuals without central control. Ant societies are ideal models to study group behaviours performed by cooperative individuals at caste or at the colony level. In addition to the ecological constraints, such as the costs of maintaining patterns of interactions, the social structure might also affect the collective behaviour in ants. We tested the effect of Myrmica scabrinodis colony traits (number of queens, colony size, and colony age structure) on four major collective behaviours (aggression against intruders, removal of nestmate corpses, foraging, and colony relocation). Our results showed that neither the number of queens nor the colony size affected the level of aggression against non‐nestmates while the efficiency of corpse removal was positively correlated with both traits. The age structure of the colony influenced both the aggressiveness towards non‐nestmates and the hygienic behaviours. Subcolonies containing a higher proportion of young individuals were more aggressive and less efficient in corpse removal. All studied traits affected foraging activity, as one of the most important behaviour in colony life. Some of the ant collective behaviours, like foraging, are determined by many traits and their interaction, while others are mostly determined by one or a few major colony characteristics. Overall, our results suggest that individual tasks which generate collective behaviours depend on different intrinsic traits of the ant colony that make a timely and appropriate behavioural response possible in every situation.