Another parasitoid without a passport: the first report of the natural dispersion of Selitrichodes neseri (Hymenoptera: Eulophidae), a parasitoid of the blue gum chalcid wasp in Uruguay

Abstract

Leptocybe invasa (Hymenoptera: Eulophidae) is considered one of the main insect pests that causes economic losses in Eucalyptus spp. plantations and nurseries. This species induces gall formation in the midribs and petioles of Eucalyptus leaves, as well as in branches or trunks of seedlings. Biological control with parasitoids is considered the best strategy for their management. Selitrichodes neseri Kelly and La Salle (2008) (Hymenoptera: Eulophidae) is one of the parasitoids most employed for L. invasa control, being imported by some countries. In February 2021, we observed some specimens of S. neseri emerging from L. invasa galls in northeastern Uruguay. This work aimed to confirm the natural entry of the parasitoid S. neseri in Uruguay and its potential distribution. We conducted surveys to collect L. invasa galls in 45 localities nationwide from March 2021 to April 2023. We performed a S. neseri potential distribution model with MaxEnt and Bioclim. We found the presence of S. neseri in 6 of them, all near Brazil. 755 adult parasitoids (304 ♂, 451 ♀) have emerged from the galls. The climatic variables that contributed most to this model were Precipitation Seasonality (40.5) and Isothermality (11.5). Our results indicate that a large part of the country presents a moderately suitable habitat to optimal habitat for the establishment of S. neseri. The model shows that southern Brazil would present optimal conditions for this species. It may have spread from that country. This is the first time that the natural entry of S. neseri has been reported.