Morphological characteristics for sexing living adults of Chaetoptelius vestitus (Coleoptera, Curculionidae)

Abstract

Abstract The pistachio bark beetle, Chaetoptelius vestitus (Mulsant & Rey, 1861) is a serious pest of pistachio trees. Despite its phytosanitary importance, some aspects of its biology are still unclear. For example, determining the sex of this beetle is usually complicated by the lack of a discrete, externally visible gender-specific character. Here, the morphological characteristics of C. vestitus were studied in order to detect discriminative features for sexing living beetles. The shape of the seventh visible tergite effectively enabled the separation of the sexes. This method can be quickly learned, is non-destructive and permits sex determination of living C. vestitus adults with 100% accuracy and without damaging the insects. Sex determination using external morphology was confirmed by dissection under a stereomicroscope and by rearing experiments. These morphological criteria were further successfully verified on insects collected on seven other sites in Tunisia.