Attractiveness of Tagetes erecta L. and Capsicum annuum L. to Aphidius platensis Brethes (Hymenoptera: Braconidae: Aphidiinae): behavior, survival, nutrient reserve and chemical profile of the plants

Abstract

Conservative biological control aims to maintain and increase populations of natural enemies in agricultural crops, providing flowering plants as a food source. Floral resources become nectar and pollen, important for feeding adults of parasitoids. Improve the performance of parasitoids, prolong longevity and increase fecundity, as well as the resources they are capable of, and usually the parasitoids. The aim of this study was to investigate whether marigold flowers Tagetes erecta L., influence the behavior, biology and nutrition of the aphid parasitoid Aphidius platensis Brethes, to collect and identify the VOCs of marigold (blooming and non-blooming) and sweet pepper plants involved in olfactory attractiveness of A. platensis. Females parasitoids exposed to marigolds, spent more time walking and parasitizing the aphids Myzus persicae Sulzer or Schizaphis graminum Rodani aphids and subsequently had higher parasitism rates. The parasitoid without access to marigolds spent more time stationary and marginally more time grooming, however, the time spent probing, emergence rate, and the sex ratio were not affected. Survival was increased in the presence of marigold in relation to water and the marigold is a source of nutrients (lipids, glycogen and sugar) for A. platensis. With respect to olfactometry, marigold blooming, marigold blooming + sweet pepper and infested sweet pepper attracted A. platensis. The volatile analysis showed blooms T. erecta, emits VOCs that influence the olfactory preference, in the attraction of A. platensis. Fatty acid derivatives (DAGs) were found in higher numbers in flowering marigolds. Infested sweet peppers were more attractive to A. platensis than intact sweet peppers. These results suggest that marigold blooming can optimize the biological control of aphids by A. platensis.