Diversity of Hymenopteran Parasitoids in Coffee Plantations under Agroecological Transition and Its Impact on Coffee Leaf Miner (Leucoptera coffeella) Infestations

Abstract

The biodiversity of natural competitors is vital to key ecosystem services and agroecosystems’ benefits to society. The abundance and richness of hymenopteran parasitoid communities, and subsequently their services, are dependent on the variety of habitats in the different agroecological landscapes. Here, we monitored the fluctuation of predatory wasps and hymenopteran parasitoid populations and their impacts on coffee leaf miner infestations under different coffee plantation landscapes. Thus, 24 sampling plots were arranged in four cultivation systems: conventional (CONV), in transition to organic shaded (T.OSH), in transition to organic full-sun (T.OFS), and without pesticide (T.WOP). In each plot, leaves with intact mines were collected randomly once a month over a period of 23 months. Parasitoid species, coffee leaf miner infestation, predation, and parasitism were assessed based on the emerged parasitoids and wasps’ activity signs in the mines. The data on parasitoids revealed the presence of 621 hymenopteran parasitoids, of which, 420 were Braconids and 201 were Eulophids. Overall, the abundance of braconid specimens (67.6%) was greater, but the species richness was higher in Eulophids. The highest species richness of L. coffeella parasitoids was in T.OSH and T.OFS. Furthermore, in the coffee plants evaluated, the coffee leaf miner population is well established and does not cause economic damage, as the spontaneous action of predatory wasps and parasitoids, in addition to climatic factors, contributes to regulating these pest infestations. Of these parasitoids, the braconid Orgilus niger and Stiropius reticulatus were found to be promising and well-adapted control provider species.