First record of Necremnus leucarthros (Nees, 1834) (Hymenoptera: Eulophidae) as a parasitoid of Hypera postica (L.Gyllenhal, 1813) in Uzbekistan
Abstract
For the first time in Uzbekistan, the parasitoid Necremnus leucarthros (Nees, 1834) (Hymenoptera: Eulophidae) is recorded as a natural enemy of the alfalfa weevil Hypera postica (Gyllenhal), a major pest in alfalfa agroecosystems. Field studies conducted in 2024–2025 in Tashkent Region, combined with laboratory observations, revealed a high level of parasitism. Analysis of 4,580 H. postica cocoons showed that 46.7% were parasitized in 2024 and 54.1% in 2025. A total of 25,578 specimens of N. leucarthros emerged from the collected cocoons. The mean number of parasitoids per cocoon ranged between 10.3 and 11.9 individuals. Morphological characteristics of adults and larvae, as well as key aspects of the species’ biology, are described, including its narrow host specialization and accelerated development (5–7 days from parasitism to adult emergence). Laboratory observations showed that females feed on host hemolymph and prefer third-instar larvae for oviposition. The increasing rate of parasitism and high survival of offspring indicate a significant role of N. leucarthros in the natural regulation of H. postica populations. These findings expand the known distribution of the species and confirm its potential as a promising biological control agent for alfalfa protection in Central Asia.