Laboratory of Zoology, University of Mons, Mons, Belgium.
PLoS One. 2012;7(9):e43053. doi: 10.1371/journal.pone.0043053. Epub 2012 Sep 20.
Social parasites exploit the colony resources of social insects. Some of them exploit the host colony as a food resource or as a shelter whereas other species also exploit the brood care behavior of their social host. Some of these species have even lost the worker caste and rely completely on the host's worker force to rear their offspring. To avoid host defenses and bypass their recognition code, these social parasites have developed several sophisticated chemical infiltration strategies. These infiltration strategies have been highly studied in several hymenopterans. Once a social parasite has successfully entered a host nest and integrated its social system, its emerging offspring still face the same challenge of avoiding host recognition. However, the strategy used by the offspring to survive within the host nest without being killed is still poorly documented. In cuckoo bumblebees, the parasite males completely lack the morphological and chemical adaptations to social parasitism that the females possess. Moreover, young parasite males exhibit an early production of species-specific cephalic secretions, used as sexual pheromones. Host workers might thus be able to recognize them. Here we used a bumblebee host-social parasite system to test the hypothesis that social parasite male offspring exhibit a chemical defense strategy to escape from host aggression during their intranidal life. Using behavioral assays, we showed that extracts from the heads of young cuckoo bumblebee males contain a repellent odor that prevents parasite males from being attacked by host workers. We also show that social parasitism reduces host worker aggressiveness and helps parasite offspring acceptance.
社会性寄生虫会利用社会性昆虫的巢穴资源。有些寄生虫会将宿主巢穴当作食物或庇护所，而其他物种还会利用宿主的育幼行为。有些物种甚至已经失去了工蜂阶层，完全依赖宿主的工蜂来养育后代。为了避免宿主的防御和绕过其识别码，这些社会性寄生虫已经发展出了几种复杂的化学渗透策略。这些渗透策略在几种膜翅目昆虫中得到了深入研究。一旦社会性寄生虫成功进入宿主巢穴并融入其社会系统，其新生的后代仍然面临着同样的挑战，即避免被宿主识别。然而，后代在宿主巢穴中生存而不被杀死所使用的策略仍然记录甚少。在布谷蜂中，雄性寄生虫完全缺乏雌性所具有的形态和化学适应性来进行社会性寄生。此外，年轻的寄生虫雄性会早期产生特定物种的头部分泌物，用作性信息素。因此，宿主工蜂可能能够识别它们。在这里，我们使用了一种熊蜂宿主-社会性寄生虫系统来测试这样一个假设，即社会性寄生虫雄性后代会表现出一种化学防御策略，以逃避宿主在其巢内生活期间的攻击。通过行为分析，我们发现，年轻的布谷蜂雄性头部提取物含有一种驱虫气味，可防止寄生虫雄性被宿主工蜂攻击。我们还表明，社会性寄生会降低宿主工蜂的攻击性并有助于寄生虫后代的被接受。
