Using morphological characteristics to distinguish between male and female larvae and pupae of the groundnut leafminer, Aproaerema modicella (Deventer) (Lepidoptera: Gelechiidae)

Abstract

The groundnut leafminer, Aproaerema modicella (Deventer) (Lepidoptera: Gelechiidae) is a well known groundnut pest in Asia. It was first reported in east Africa during 1998 after which it rapidly spread throughout East and southern Africa. The adult is a small brownish-grey moth and it difficult to distinguish between the different sexes even under a stereomicroscope. Research on pest behaviour is hampered by the fact that male and female moths cannot be distinguished. The aim of this study was to identify distinguishing morphological characteristics of male and female larvae and pupae that are visible with the naked eye or under a stereomicroscope. The presence of pink coloured gonads which are easily visible through the cuticle was a distinguishing characteristic of male larvae. The position of the male genital aperture is a useful distinguishing characteristic present in male pupae. It is situated further away from the proximal side of the last abdominal segment, compared to the aperture of oviduct and bursa copulatrix of the female.