Comparative morphological analysis of mature larvae of eight Vespa Linnaeus, 1758 species (Hymenoptera, Vespidae) in South Korea

The social wasp genus Vespa, encompassing insects commonly referred to as hornets, consists of 22 species that are predominantly distributed across the Palearctic and Indomalayan regions. These harmful pests, often spread through trade, pose risks to public health. Hornet larvae undergo development within the protected environment of nests.

Hence, they may exhibit more conserved characteristics than adults, which face direct selection pressure. To date, larval morphology has been studied in only approximately half of the 22 known hornet species, and in-depth comparative research on species within the genus Vespa is scarce. In South Korea, comprehensive descriptions and identification keys for the eight reported species and two subspecies are lacking.

To address this gap, this study aimed to provide morphological descriptions and identification characteristics of mature larvae from eight Vespa species in South Korea. Between 2021 and 2024, larvae were collected from nests across South Korea. The larvae were observed under scanning electron microscopy, optical microscopy, and stereo microscopy to evaluate various morphological characteristics.

Results indicated that distinguishing hornet larvae morphologically from larvae of other taxonomic groups is challenging. Specifically, no significant morphological differences were noted between V. velutina nigrithorax and V. simillima simillima. The lack of distinctive morphological features in larvae complicates taxonomic identification, making it more challenging compared to the identification of adult specimens.