Prey sex pheromone as kairomone for a new group of predators (Coleoptera: Dasytidae, Aplocnemus spp.) of pine bast scales

During the last decades, an increasing number of predators were found to use specific prey pheromones as chemical cues. Beyond its ecological relevance, this knowledge has practical applications on insect conservation and pest control. In this study, we present first evidence that two species of the family Dasytidae (Coleoptera)Aplocnemus brevisRosenhauer andA. raymondiSainte-Claire Deville use the sex pheromone of the pine bast scaleMatsucoccus feytaudiDucasse (Hemiptera: Matsucoccidae) as kairomone to locate this prey. The feeding habits and biology ofAplocnemusspecies are practically unknown. In the laboratory, the adults ofAplocnemussp. acceptedM. feytaudiegg masses as food source as well as other diets. Females represented more than 90% ofAplocnemussp. attracted to the pheromone lures. We believe that females use this olfactory cue to locate suitable places for oviposition and that larvae are the predators ofMatsucoccus. This study further demonstrates that the response to the kairomone elicited short prey searching times, about 23% of the individuals appeared less than 12 min after lure exposure, being consistent with the hypothesis of prey specialization. Habitat and geographical distribution predict an ancestral association ofA. breviswithM. feytaudiand ofA. raymondiwithM. pini. Nevertheless, a recent prey shift ofA. raymondito the invasiveM. feytaudiin Corsica is in progress.