Herbivoria múltipla na indução de voláteis atrativos a Cycloneda sanguinea (Linnaeus, 1763) (Coleoptera: Coccinellidae)

Abstract

Natural enemies of insect herbivores can use volatile organic compounds (VOCs) released by plants as cues for finding suitable foraging environments. When a plant is damaged by a herbivore, it can change its VOC profile, increasing the attraction of these natural enemies. There is evidence that different herbivore species can activate alternative biochemical pathways in plants and these may have positive or negative interactions between them, but little is known about how this can interfere with the attraction of predators. Ladybugs of the family Coccinellidae are predatory insects in all stages of life, and have a high searching efficiency, attacking aphids as their preferred food source. Aphids are phloem-feeding insects, mainly inducing the shikimic acid pathway. A little known aspect is how the interactions mediated by plant VOCs happen when there is more than one species of herbivore feeding on the plant. This work aimed to evaluate the olfactory response of the ladybug Cycloneda sanguinea to plants damaged by more than one species of aphid. Olfactometer bioassays were carried out, where odors of sweet pepper plants were offered without damage and damaged by the aphids Myzus persicae, Aphis gossypii or by both. Plants damaged by aphids A. gossypii and M. persicae were significantly more attractive than plants without damage. Plants damaged by both aphids at the same time, or sequentially were more attractive than undamaged plants. From this study we conclude that the ladybug is attracted by VOCs from plants damaged by aphids, and that multiple damage does not interfere with attraction of this natural enemy. Studies with several herbivores attacking one plant are necessary to understand better the how changes in plant VOCs suffering multiple herbivory affect predator-prey interactions.