Semiochemical studies of Gonipterus sp. 2 (Curculionidae) and pheromone-based masstrapping of Nudaurelia clarki (Saturniidae) in South Africa

Abstract

In this study, we investigated the pheromones of Gonipterus species 2 (Coleoptera: Curculionidae) and Nudaurelia clarki (Lepidoptera: Saturniidae). These insects are two South African plantation pests that have caused the forestry industry tremendous economic losses due to defoliation. The development of pheromonebased management tools for these pests can ensure sustainable and effective pest control without detrimental effects to surrounding environments. Our results showed that Gonipterus sp. 2 produces at least cis- and transverbenol, which were described as putative pheromone components for G. platensis. Female headspace samples contained larger concentrations of the same volatiles than male samples. Furthermore, topical application of Juvenile hormone III does not induce pheromone production in Gonipterus sp. 2. The described pheromone of N. cytherea, Z-dec-5-en-1-yl-3-methylbutanoate, was shown to be effective for trapping N. clarki in KZN. The synthesized pheromone consisted of four electroantennographically active compounds, and attracted numerous N. clarki male moths species-specifically. We report on the first instance of female autodetection in the Saturniidae family, because female N. clarki antennae also detect the pheromone. The attractiveness of the same pheromone to both N. cytherea and N. clarki, together with preliminary genetic evidence that shows identical cytochrome oxidase I sequences between these species, reveal that these two species might actually be one. Future development of pheromone-based pest management strategies requires confirmation of the attractiveness of cis- and transverbenol to Gonipterus sp. 2, and optimizing N. clarki pheromone-based trapping for use in mass-trapping or mating disruption mechanisms.