Four morphologically cryptic species of the Bactrocera dorsalis fruit fly complex (B. dorsalis s.s., B. papayae, B. carambolae and B. philippinensis) are serious agricultural pests. As they are difficult to diagnose using traditional taxonomic techniques, we examined the potential for geometric morphometric analysis of wing size and shape to discriminate between them. Fifteen wing landmarks generated size and shape data for 245 specimens for subsequent comparisons among three geographically distinct samples of each species. Intraspecific wing size was significantly different within samples of B. carambolae and B. dorsalis s.s. but not within samples of B. papayae or B. philippinensis. Although B. papayae had the smallest wings (average centroid size=6.002 mm±0.061 SE) and B. dorsalis s.s. the largest (6.349 mm±0.066 SE), interspecific wing size comparisons were generally non-informative and incapable of discriminating species. Contrary to the wing size data, canonical variate analysis based on wing shape data discriminated all species with a relatively high degree of accuracy; individuals were correctly reassigned to their respective species on average 93.27% of the time. A single sample group of B. carambolae from locality ‘TN Malaysia’ was the only sample to be considerably different from its conspecific groups with regards to both wing size and wing shape. This sample was subsequently deemed to have been originally misidentified and likely represents an undescribed species. We demonstrate that geometric morphometric techniques analysing wing shape represent a promising approach for discriminating between morphologically cryptic taxa of the B. dorsalis species complex.

Four distinct Franciscana Management Areas (FMAs) have been proposed based on several lines of evidence including genotype, phenotype, population response and distribution. To determine if differences in external morphology fit this division, a canonical variate analysis was carried out for males and/or females from FMAs I to IV using up to 14 characters. A total of 78 adult specimens were analysed. More than 90% of the differences between groups were summarized by three canonical variates. Females were larger than males in all areas. Females from FMA IV were of intermediate length between those from FMA I and FMA III and individuals from FMA II were smaller than those from all other areas. Position of dorsal fin and morphology of the anterior body region, differentiate individuals from FMA I and FMA III. Morphological differences found in this study give additional support for the proposed FMAs. Since habitat characteristics and franciscana feeding ecology vary regionally, it is possible that observed morphological differences are due to ecological divergence for niche occupation. The indication of a discontinuous distribution, consistency between genetic and morphological evidence, and a short time genetic divergence, might indicate that franciscanas inhabiting FMA I represent a distinct subspecies.