Platygastridae (Hymenoptera) Egg Parasitoids of Mirid Bugs in Cereal Fields

Abstract

A field-based faunistic survey was conducted to document Platygastridae (Hymenoptera) egg parasitoids associated with mirid bugs in cereal cropping systems, with emphasis on species composition, host associations, and their potential role in natural pest regulation. Systematic sampling of cereal fields revealed the presence of multiple mirid bug species infesting wheat, barley, and maize, with egg masses predominantly deposited on leaf surfaces and stem tissues. Parasitized eggs collected from field populations were reared under laboratory conditions to obtain adult parasitoids for identification using morphological characters supported by COI gene sequencing. Several platygastrid taxa were recorded, indicating a diverse egg parasitoid complex actively exploiting mirid populations in cereal agroecosystems. Parasitism levels varied across locations and crop stages, with higher rates observed during peak mirid oviposition periods under moderate temperature and humidity conditions. The synchrony between parasitoid emergence and host egg availability suggests strong temporal adaptation and effective host exploitation strategies. Phylogenetic analysis confirmed clustering of recovered parasitoids within established Platygastridae lineages, with limited intraspecific variation among populations, indicating stable regional genetic structure. Environmental factors such as crop density, pesticide exposure, and habitat heterogeneity influenced parasitoid abundance and parasitism efficiency. The study highlights the ecological importance of Platygastridae as natural enemies contributing to the suppression of mirid bug populations in cereal-based systems. Conservation of these parasitoids through reduced pesticide input and habitat management may enhance their biological control potential. These findings provide baseline information for integrating egg parasitoids into sustainable pest management programs aimed at reducing mirid bug damage in cereal agroecosystems.