First record of Megastigmus transvaalensis (Hussey) (Hymenoptera: Chalcidoidea: Torymidae) in northwestern Argentina. Effect on drupes of Schinus areira L. (Sapindales: Anacardiaceae)

Abstract

In studies designed to investigate the entomofauna associated to Schinus areira L. we detected the presence of a species of Megastigmus Dalman (Hymenoptera: Chalcidoidea: Torymidae) which affects the fruits of this plant. The objectives of this study were: to identify the species of Megastigmus and the morphotypes of males, to determine the percentage of infestation in drupes of S. areira and to evaluate the distribution of this species in high altitude areas of Jujuy (Argentina). Fruits of S. areira were collected between 2007 and 2012, at five sites in the Jujuy province, located between 2300 and 2800 m. The adults of M. transvaalensis (Hussey) emerged in the laboratory. This is the first record for northwestern Argentina, with infestation values between 6.29 and 26.48 %. We evalu- ated the sex ratios at two sites, Maimará and Tilcara, with a predominance of males over females (2.7:1 and 2.1:1, respectively) and three morphotypes of males (male-A: yellow male; male-I: intermediate male and male-N: black male), the yellow male morphotype being the most abundant (80 %). This exotic species is widely distributed in semi-arid zones of Jujuy related to the distribution of the host plant.