Differentiation in wing shape in the Bactrocera tau (Walker) complex on a single fruit species of Thailand

Abstract

The Bactrocera tau complex contains fruit fly pests which damage several species of cucurbit crops. Two cryptic species, A and C, of the B. tau complex both occur on the host fruit Momordica cochinchinensis. In this study, wing geometric analysis was used to differentiate the B. tau complex on M. cochinchinensis. A total of 586 wings (297 males, 289 females) were discriminated into two groups corresponding to the reference species A and C of the B. tau complex. B. tau A and C were reclassified at higher than 96% and 99% accuracy, respectively. B. tau C had larger wings than B. tau A. Interspecific differentiation was significant due to wing size, indicating that wing shape can be used to separate the species. The B. tau C was found to be the dominant species on M. cochinchinensis. A classification tree based on Mahalanobis distances suggested that the variation within B. tau C is related to seasonal variation. The variation among seasonal populations was similar in males and females. Wing shape analysis, which can differentiate between species within cryptic complexes helping to detect variation within species, may have important applications in pest control programs.