Morphometric based differentiation among Trichogramma spp.

Abstract

Genus Trichogramma Westwood is being utilized in various biological control programme worldwide. Trichogramma spp. are egg parasitoids which lay their eggs inside the host eggs. More than 240 species are known, of which, 45 species are recorded from India. It is quite difficult to identify and differentiate among the species of Trichogramma due to smaller size. In present study, we hypothesized a methodology to identify the Trichogramma species based on potential morphometric characteristics. The males and females of five different species of Trichogramma namely, T. brassicae, T. chilotraeae, T. danaidiphaga, T. danausicida and T. dendrolimi were morphometrically analysed. A total of 33 characters in males and 27 in females were taken into consideration for morphometric identification and analysis using principal component method. It was observed that few characters of male like body length, length of flagellar hair, maximum marginal hair length of fore wing, genitalia characters including aedeagus length, distance between chelate structure and gonoforceps, and others were identified as important morphometric characters. Similarly, in females, ovipositor length, body and head length, eye width, antennal club width and number of setae in forewings were found important for taxonomic identification. Male and female of each species are clearly identified from high definition microscopic images.