Insect pests of stored products can result in millions of dollars in damaged goods around the world. Some of these insects enter a diapause-like state, where they arrest developing into adults until environmental cues indicate optimal conditions. The warehouse beetle, Trogoderma variabile Ballion (Coleoptera: Dermestidae) and other dermestids can remain as larvae for years. As larvae, these beetles continue to grow and molt as long food resources are available. Using reduced temperatures, we prolong the larval stage of T. variabile for 30 d, followed by return to warmer temperature. We group larvae in sets of 5, 10, 15, or 20 with or without food to determine the timeline and proportion of insects that will develop into adults under different environmental conditions. Our preliminary results suggest that diapausing larvae have an increased time to pupate and develop into adults compared to larvae that have not been held at lower temperatures, especially when kept with fewer conspecifics. We also find that food had little impact on diapausing larvae development. We find less cannibalism in diapausing larvae than in control larvae, which could lead to higher population numbers over time. Our results suggest that these insects have little reliance on food for adult development and that diapausing larvae have a delay in their developmental program even when placed at a warmer temperature. Because these beetles can remain in the larval stage for long durations, focusing management efforts to disrupt development at the larval stage could be a good target for management tactics.
