Wing shape as a potential discriminator of morphologically similar pest taxa within theBactrocera dorsalisspecies complex (Diptera: Tephritidae)

Abstract

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.

Molecular clock analysis on fiveBactroceraspecies flies (Diptera: Tephritidae) based on combination ofCOIandNADHsequences

“…For this reason, several studies have been conducted to clarify the taxonomic puzzles, for example on taxonomy, molecular genetics, behaviour, chemical and cytogenetic reactions (Tan et al 2011;Khamis et al 2012;Schutze, Jessup, et al 2012Boykin et al 2013;Krosch et al 2013;Schutze et al 2013;Tan et al 2013). Despite the difficulties, several discoveries have been made at a basic level on its taxonomic situation via the implementation of the tools that have been discussed above.…”

“…Besides that the differences were determined to be in the volatile components of male reproductive organs (Wee & Tan 2005). Furthermore, the wing shape in geometric morphometric analysis (Schutze, Jessup, et al 2012) and the morphometry of the male aedeagus (Iwahashi 2001) have been useful in discerning members of the B. dorsalis species complex. The time divergence estimated from the fossil record of the Tephritidae family also showed that the well-resolved B. dorsalis species complex with all members shares a common ancestor at 6 million years ago (MYA) (in the Pliocene period) .…”

The evolution of avian wing shape and previously unrecognized trends in covert feathering

“…Orientation (or rotation) and scale effects attributed to each specimen are removed during analysis [43], and subtle sources of variation that are not easily summarized by simple linear measurements are more completely captured [42,[44][45][46]. Although landmark-based morphometric analyses have been widely used to investigate the relationships between form and function in insects [47], the sole previous study in birds investigated only six closely related species [46]. So far to our knowledge, no landmark-based morphometric analysis has been used to investigate broader patterns of variation in wing shape across Aves.…”

Wing morphometrics as a possible tool for the diagnosis of the Ceratitis fasciventris, C. anonae, C. rosa complex (Diptera, Tephritidae)

“…Seventeen homologous type I landmarks (Bookstein 1997) consisting of points at which a wing vein meets the edge of the wing, or wing vein and cross-vein intersections were selected. Thirteen of the landmarks were homologous to those of Schutze et al (2011), and an additional four were chosen to try to obtain a higher resolution of species and of genotypic clusters. No landmarks were chosen in the anterior and posterior regions of the wing because these areas are most easily damaged.…”