Can morphological analysis reveal the existence of subspecies of Praon exsoletum (Nees, ۱۸۱۱) (Hymenoptera: Braconidae, Aphidiinae) in various geographical regions?

In this study, ۱۳ different biotypes of Praon exsoletum were investigated based on selected morphological characteristics. This species is specialized parasitoid of Therioaphistrifolii on alfalfa and clover. Traditional morphometric analysis was used to obtain three meristic and ۱۵ continuous characters. The analysis of variance showed that P. exsoletumbiotypes differ in many morphometric traits. Moreover, all biotypes displayed their maximum differences in six morphological characters as follows:(۱) number of antennal segments;(۲) inter-tentorial/tentorio-ocular distance;(۳) length/width of ovipositor sheath;(۴) length/width of second flagellar segment; (۵)length/width of third flagellar segment and (۶) number of longitudinal placodes on second flagellar segment. The discriminant function analysis indicated۴۵.۲۳% of correct assignment of specimens to the a priori designated groups of specimens. The results indicated an overlapping of analyzed biotypes according to selected morphological characters. On the other hand, geometric morphometrics analysis applied on forewings, the size and the shape revealed statistically significant differences. Eleven homologous landmarks were selected. The ANOVA (p < ۰.۰۰۰) and MANOVA (P= ۰.۰۰۰) showed that there were significant differences in size and shape of forewings. Visualization of the distribution of individuals was presented using Principal component analysis and Canonical variate analysis. On whole, the result of this investigation showed that R۱ and the radial veins (end of Rs and M) tend to be short. Furthermore, the USAbiotype introduced is positioned near all other analyzed biotypes of P. exsoletum. Among the selected morphological characters, four characters namely (۱) length of wing/length of R۱; (۲) length of wing/length of stigma; (۳) length of first/third flagellar segment and (۴) width of first/third flagellar segment were first considered for morphometric study in Praon and P. exsoletum species. Our results showed lack of subspecies for P. exsoletum.

کلیدواژه ها:

Geometric morphometrics ، landmark ، discriminant function analysis