Quantifying Variation in the Shape of the Valvae in Thaumatotibia leucotreta (Lepidoptera: Tortricidae)

Recent studies have demonstrated that geographically isolated populations of Thaumatotibia leucotreta (Meyrick), an important pest of some crops in southern Africa, show minor genetic divergence. Because sexual selection can cause rapid evolution of male genitalia in insects, particularly in widespread, polyphagous species, differences in the morphology of these structures among different populations may be evidence of divergence. Hence, variation in the shape of the valva in the male genitalia within and among three different populations of T. leucotreta was analysed using geometric morphometrics. Although some variation was detected among mean population values for certain traits, there was no overall pattern. Principal component analysis showed no distinct clustering of valval shape among populations, providing no evidence for divergence in genitalic structures, at least in the shape of the valva.