Résumé
Significance: In animal societies, social life often generates male mating harassment. How do communal animals manage such conflicts without escalating antagonistic relationships? In the Sahara Desert, we studied the mating system of gregarious-behaving desert locusts, the world’s most destructive locust. Despite being widespread and abundant during plagues, its populations are otherwise difficult to access, and its reproductive behaviors in the field are understudied. We show that female locusts behaviorally overcome the costs of male mating harassment: females occupy separate sites before and after mating. Only females with ripe ovaries arrive at male-biased lekking groups. Hence, substantial social conflicts can be simply managed by behaviors. These findings invite to explore theevolutionary hypotheses behind lekking with a density-dependent plastic species.Abstract: Male mating harassment may occur when females and males do not have the same mating objectives. Communal animals need to manage the costs of male mating harassment. Here, we demonstrate how desert locusts in dense populations reduce such conflicts through behaviors. In transient populations (of solitarious morphology but gregarious behavior), we found that nongravid females occupied separate sites far from males and were not mating, whereas males aggregated on open ground (leks), waiting for gravid females to enter the lekking sites. Once a male mounted a gravid female, no other males attacked the pair; mating pairs were thereby protected during the vulnerable time of oviposition. In comparison, solitarious locusts displayed a balanced sex ratio in low-density populations, and females mated irrespective of their ovarian state. Our results indicate that the mating behaviors of desert locusts are density dependent and that sex-biased behavioral group separation may minimize the costs of male mating harassment and competition.