Arsenophonus : A Double-Edged Sword of Aphid Defense against Parasitoids.

It is widely accepted that endosymbiont interactions with their hosts have significant effects on the fitness of both pests and beneficial species. A particular type of endosymbiosis is that of beneficial associations. Facultative endosymbiotic bacteria are associated with elements that provide aphids with protection from parasitoids. (Enterobacterales: Morganellaceae) is one such endosymbiont bacterium, with infections being most commonly found among the Hemiptera species. Here, black cowpea aphids (BCAs), Koch (Hemiptera: Aphididae), naturally infected with were evaluated to determine the defensive role of this bacterium in BCAs against two parasitoid wasp species, and (both in Braconidae: Aphidiinae). Individuals of the black cowpea aphids infected with were treated with a blend of ampicillin, cefotaxime, and gentamicin (-reduced infection, AR) and subsequently subjected to parasitism assays. The results showed that the presence of does not prevent BCAs from being parasitized by either or . Nonetheless, in BCA colonies parasitized by , the endosymbiont delayed both the larval maturation period and the emergence of the adult parasitoid wasps. In brief, indirectly limits the effectiveness of . parasitism by decreasing the number of emerged adult wasps. Therefore, other members of the BCA colony can survive. acts as a double-edged sword, capturing the complex dynamic between and its parasitoids.