Abstract Mating with the best partner is a critical step in the life of an organism, especially when there is a lifelong commitment between partners. Genetic compatibility between mating partners is thought to be an important driver of mate choice, either through inbreeding and/or outbreeding avoidance. Social species provide very interesting systems where related group members may affect each other’s mating choice. This is the case of social insects, where sterile workers could actively drive the mating choice of their sister queens. Here, we performed two series of dyadic choice tests under laboratory conditions in the low dispersing ant Cataglyphis piliscapa. We tested (i) whether a virgin queen chooses between two males of varied genetic proximity (allopatric vs. sympatric) and (ii) whether workers modulate male access to the queen. In tests without worker, allopatric and sympatric males attempted mating equally. Allopatric males succeeded mating more often, but there was no indication of queen choice. When present, workers attacked allopatric males thrice as much as sympatric males. Workers presence reduced the frequency of mating attempts, and more so for the males that they strongly aggressed. We suggest that worker aggressions may have stronger effects in the field where males attempt to mate for many hours and discuss the factors that could favor this behavior. We discuss our results in the light of the very strong population genetic differentiation of C. piliscapa , which could favor outbreeding avoidance, and of its peculiar reproductive system.
Doums et al. (Thu,) studied this question.