Simple methods to devitalize beetles under laboratory conditions

Authors: BLANCO, CARLOS - US Department Of Agriculture (USDA); RADAVICH, ANNE - Us Army Public Health Command (USAPHC); Portilla, Maribel

Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/21/2025
Publication Date: 7/28/2025
Citation: Blanco, C.A., Radavich, A., Portilla, M. 2025. Simple methods to devitalize beetles under laboratory conditions. Southwestern Entomologist. 50:1-8. https://doi.org/10.3958/059.050.0312.
DOI: https://doi.org/10.3958/059.050.0312

Interpretive Summary: The United States Department of Agriculture’s Animal and Plant Health Inspection Service (USDA-APHIS) regulates the domestic movement and importation of most arthropods, providing general guidelines for their transport and containment. However, practical guidance on procedures to render these insects nonviable—particularly when they are no longer needed or when illegally imported plant pests must be destroyed—is limited. While insecticidal substances and methods such as autoclaving or physical destruction can achieve complete devitalization, their application in laboratory or enclosed settings may pose safety risks to personnel or require substantial financial investment. Encouragingly, simple and cost-effective methods have been shown to fully devitalize certain Lepidoptera and ant species under laboratory conditions. In this report, we expand upon the efficacy of these procedures by evaluating their effectiveness against six surrogate beetle species.

Technical Abstract: Beetles (Coleoptera) are well-suited for laboratory studies due to their high species diversity, rapid reproductive rates, minimal space requirements for rearing, and extensive knowledge of their reproductive biology. Laboratory experiments often conclude with surviving beetles that must be devitalized, and exotic or illegally imported beetles confiscated at ports of entry also require safe elimination. In this study, we evaluated devitalization methods using surrogate adults of six species: Oryzaephilus surinamensis L. (Silvanidae; sawtoothed grain beetle), Tribolium confusum Jacquelin du Val (Tenebrionidae; confused flour beetle), Sitophilus oryzae L. (Curculionidae; rice weevil), Tribolium castaneum (Herbst) (Tenebrionidae; red flour beetle), Tenebrio molitor L. (Tenebrionidae; yellow mealworm), and Zophobas morio (Fabricius) (Tenebrionidae; superworm). Independent groups of 15–40 beetles were subjected to immersion in water, water with 10% dish soap, water with 10% sodium hypochlorite, and 70% isopropyl alcohol for two hours; exposure to freezing temperatures (-5 to 1'°C) for two hours; and microwave treatment for 60 seconds. Among these, microwaving and freezing consistently resulted in complete devitalization across all six species.