D3445: Microbial dynamics in stored product insects: Implications for temperature-mediated interactions in a warming world

Understanding the dynamics of microbial communities within food facilities is essential for coordinated integrated pest management strategies, particularly with progressing climate change. Here, we present findings from a 2-year trapping study conducted at a food facility, focusing on the temporal changes in the microbial communities associated with insects captured in grain bin environments. Over a period of 19 weeks from April to October 2022 and 2023, we deployed six commercial pitfall traps, with alternating treatments of either no odor source (control) or 5 grams of clean or microbially-inoculated wheat. Traps were rotated among the grain bins during each deployment to capture full variability in the Sitophilus oryzae population and its microbial community. Weekly counts of captured weevils were recorded, and a subset of specimens (n = 5) was selected for microbial imprints in the laboratory on potato dextrose agar (PDA) where they were imaged after 3 and 5 days.  Transmission of microbial community in the laboratory was linked to average weekly temperature in the field preceding collection from MesoNet. Our results indicate significant temporal fluctuations in the abundance of weevils captured in the traps, with notable differences observed between control and wheat-baited traps. Furthermore, we found microbial transmission correlates with harvest of major grain crops in Kansas, and is also correlated with abiotic conditions such as temperature in the field preceding collection. This study underscores the importance of considering both insect behavior and microbial dynamics in the context of temperature-mediated interactions, as IPM strategies are refined under climate change.