Molecular identification of Trichogramma Westwood, 1833 species as egg parasitoids of Ostrinia nubilalis (Hübner, 1796) in corn production areas of Sakarya province in Türkiye (Insecta: Lepidoptera, Hymenoptera)

Abstract

The study focuses on using ITS2 sequences from rDNA for systematic studies of Trichogramma Westwood, 1833 species. ITS2 sequences have shown to be reliable in distinguishing Trichogramma species. Accurate identification of natural enemies is essential for biological control programs. The aim of the study is to compare rDNA-ITS2 sequences from Trichogramma samples with sequences in GenBank. By utilizing ITS2 as a barcode, the study aims to achieve dependable species identification and evaluate genetic diversity within Trichogramma species. ITS2 sequence was used to differentiate two Trichogramma species, Trichogramma euproctidis (Girault, 1911) and Trichogramma brassicae Bezdenko, 1968 collected from Sakarya province of Türkiye. The ITS2 sequences of the two Trichogramma species were aligned using Clustal W, and genetic distances as well as a phylogenetic tree were calculated using MEGA V7.0. In the study, rDNA-ITS2 sequences of fifty four Trichogramma specimens were confirmed in GenBank. Additionally Mfold web server was used to predict secondary structures of ITS2 sequences. The construction of all secondary structures was carried out at 37ºC using RNA version 2.3 default parameters. The study identified a new species that expands the Trichogramma fauna of Sakarya Province in northwestern Türkiye, where only one species had previously been detected through rDNA-ITS2 sequence analysis. This shows the importance of molecular markers in species identification and biological control strategies.