Are bug meals bug free? Stored-product insect infestations in edible insect processing

Insect meal production is expected to further rise in the coming years. As with all agricultural commodities, insect meals may be vulnerable to infestations by storage insects. However, information on the susceptibility of insect meals to infestations by stored-product insects is rather limited. To fill this gap, we investigated the susceptibility of substrates based on insect meals made of Tenebrio molitor L.or Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae) larvae to major stored-product insects. Both T. molitor and A. diaperinus are promising insect species for industrial utilization and commercial large-scale production. In a first screening, A. diaperinus meal was artificially infested with adults of 13 major storage insects. Based on our results several insect species, e.g. Tribolium castaneum, Trogoderma granarium, T. molitor, A. diaperinus and Lasioderma serricorne, can develop significant populations on A. diaperinus meal. In another series of bioassays, we evaluated the susceptibility of wheat bran-based substrates amended withdifferent percentages of A. diaperinus or T. molitor larvae meal. It was shown that T. molitor and T. confusum can successfully infest 100% T. molitor meal and T. molitor-based substrates. Similarly, A. diaperinus, T. molitor and T. castaneum developed significant populations on 100% A. diaperinus meal and related substrates, however, the development of all species on 100% insect meal was slower in comparison to wheat bran. To conclude, T. molitor and A. diaperinus larvae meal, as well as insect meal-based substrates with different percentages of wheat bran, were found to be susceptible to infestations by major stored-product insects.