Acute Contact and Oral Testing of Chemical Compounds on Vespa velutina nigrithorax (Hymenoptera, Vespidae) Under Laboratory Conditions.

Standardized laboratory assays are essential for generating reproducible and comparable data in toxicology. Although acute contact and oral toxicity tests are widely applied in pesticide risk assessment, these approaches have rarely been adapted for social vespids. Vespa velutina nigrithorax, an invasive hornet in Europe and East Asia, is commonly managed through chemical control, yet treatment efficacy may vary depending on the route of exposure and other biological factors. This protocol describes a standardized method to assess acute contact and oral toxicity of chemical compounds in adult V. v. nigrithorax workers under controlled laboratory conditions. Hornets are collected in the field, individually housed, and exposed either to topical applications on the thorax or to spiked food sources. Mortality is monitored over 48-96 h and analyzed using appropriate statistical approaches to estimate lethal endpoints. This protocol enables comparison among compounds and exposure routes and provides a practical framework for toxicity screening in hornets. Key features • Builds upon the ecotoxicological methodology developed by Souto et al. [1,2]. • Describes a standardized laboratory acute toxicity test for Vespa velutina nigrithorax, adaptable to other Vespa social and predatory species. • Includes field collection, laboratory maintenance, and acute toxicity assays for oral and contact exposure with behavioral and mortality endpoints. • Compatible with Organization for Economic Co-operation and Development (OECD) ecotoxicological frameworks, enabling reproducible dose-response analyses and comparisons with other insect toxicity studies.