Discrimination of Eubazus (Hymenoptera, Braconidae) sibling species using geometric morphometrics analysis of wing venation

Abstract

Complexes of sibling and cryptic species are encountered frequently in parasitic Hymenoptera. Geometric morphometrics is a useful tool to detect minimal morphological variations, which often are undetectable by traditional morphological studies and even by classical morphometric approaches. We applied geometric morphometrics to wing venation to assess a complex case of sibling species in the genus Eubazus (Hymenoptera, Braconidae), parasitoids of conifer bark weevils of the genus Pissodes (Coleoptera, Curculionidae). The results and methods were compared with previous taxonomic studies on the same species, involving classical multivariate morphometrics, isoenzyme analyses, cross‐mating experiments and biological observations. Geometric morphometrics confirmed the previous division into four distinct species. However, this approach enabled the four species to be separated simultaneously, with a reliability of 98.6% for well‐classified females and 93.1% for males. A similar result in previous studies was obtained only by combining isoenzyme analyses and several canonical variate analyses, including many morphometric characters. Furthermore, measurements of wing venation were less time‐consuming, more reliable and required less prior knowledge of braconid taxonomy than the measurements needed for the classical morphometrics methods. Geometric morphometrics was used also to test the effect of host species on wing shape. Several female populations of Eubazus semirugosus originating from three different Pissodes spp. were compared. Significant differences were found in wing shape between conspecific Eubazus from different host species. The results are discussed in relation to reproductive isolation and genetic flow between the four species.

Geometric morphometry and molecular analysis clarified the identity of Opius sp. aff. bellus (Hymenoptera, Braconidae), a fruit fly parasitoid in Brazil

“…The habitat where these species originate from can strongly influence the individual variability because interactions with biotic, such as host larvae (Villemant et al 2007), and abiotic factors (temperature, humidity, pluvial precipitation), as well as the unique features of each environment can directly affect these populations (Futuyma 1992).…”

“…The morphotypes from Amapá demonstrated longer wings, with strong compression in the medial-apical region compared to the base and were located at the upper end of the VC2 axis (positive score) (Fig 3). Because of the homology of the landmarks found in the analyzed structure and the use of cartesian coordinates, minimal morphological variations could be detected, as is common in geometric morphometry, thereby providing a powerful tool for studies on systematics (Monteiro & Reis 1999;Baylac et al 2003;Villemant et al 2007). …”

Combination of morphometric and isotopic tools for studying spring migration dynamics in Episyrphus balteatus

“…Moreover, the double influence on wing morphology of life history traits and of the conditions at the location where the individual developed creates confounding effects and reduces the power of wing morphology to determine the geographical origin. Finally, morphological differences are also often associated with genetic structure (Villemant et al 2007, Francoy et al 2011, Vicente et al 2011, Neto et al 2013. However, previous studies found no evidence for genetic structure either in relation with geographical origin (Hondelmann et al 2005, Raymond et al 2013b, or with overwintering strategy (Raymond et al 2013a) in E. balteatus.…”

“…Migration is notably known to shape wing development and to affect wing morphology in different insect taxa including dragonflies (Dockx 2007), butterflies (Johansson et al 2009) and whiteflies (Byrne 1999). Landmark-based geometric morphometrics offer better discrimination capabilities than classical morphometrics (Rohlf and Marcus 1993, Bookstein 1996, Villemant et al 2007 as they make it possible to study the shape in addition to the size of organisms. Geometric morphometrics and in particular wing geometric morphometrics have already been used in insect taxa to characterize and identify populations from different geographical origin (Alibert et al 2001, Camara et al 2006, Francoy et al 2011, Gaspe et al 2012).…”

Biodiversity in a Rapidly Changing World: How to Manage and Use Information?

“…This result was reinforced by other molecular markers, like mitochondrial DNA and cuticular hydrocarbons, which pointed in the same direction of the morphological data. It was also very informative to discriminate species with very little or no external morphological differences, like species from the genus Eubazus (Villemant et al, 2007), Bombus (Aytekin et al, 2007) and Euglossa (Francoy et al, unpublished results). Other works also indicated the efficiency of the technique in stingless bees.…”