New Faunal Records of Scelionidae (Hymenoptera) Egg Parasitoids of Stink Bugs in Soybean Agroecosystems

Abstract

Scelionid wasps (Hymenoptera: Scelionidae) are important egg parasitoids regulating stink bug populations in soybean agroecosystems, yet their diversity and distribution remain insufficiently documented in several soybean-growing regions. The present study reports new faunal records of Scelionidae associated with pentatomid egg masses collected from soybean fields. Systematic field surveys were conducted during different crop growth stages, and stink bug egg clusters were collected and reared under laboratory conditions to record parasitoid emergence. Emerged adult parasitoids were preserved and identified using standard taxonomic keys, supported by microscopic examination of diagnostic characters such as antennal segmentation, wing venation, and body sculpture. Identified taxa primarily belonged to genera Trissolcus, Telenomus, and Baryconus, representing new distributional and host association records for the region. Parasitism rates varied across sampling sites and were strongly influenced by crop phenology and stink bug abundance. Higher parasitoid activity was recorded during mid-vegetative to early reproductive stages of soybean, coinciding with peak availability of host egg masses. Environmental conditions characterized by moderate temperature and high humidity favored parasitoid emergence and survival. The study highlights the ecological importance of scelionid egg parasitoids in suppressing stink bug populations and reducing potential yield losses in soybean production systems. Documentation of these new faunal records expands the known biodiversity of egg parasitoids in agricultural landscapes and provides baseline information for future biological control programs. These findings emphasize the need for conservation of natural enemy complexes through reduced pesticide use and habitat management practices. Overall, the study supports the integration of scelionid parasitoids into sustainable integrated pest management strategies for effective stink bug control in soybean agroecosystems.