Τhe sublethal impacts of five insecticidal formulations on Oryzaephilus surinamensis behavioral traits

BACKGROUND Mortality caused by various pyrethroids, and neonicotinoids has been studied for stored‐product insects in the past, yet limited information exists on the sublethal effects they can induce to Oryzaephilus surinamensis . In the current study, the sublethal effects of deltamethrin, λ‐cyhalothrin, α‐cypermethrin, etofenprox, and the mixture of acetamiprid with d‐tetramethrin and piperonyl butoxide on the mobility of O. surinamensis in the presence or the absence of a food source was investigated. RESULTS Lethal concentrations (LCs) were lower for deltamethrin, α‐cypermethrin, and λ‐cyhalothrin (LC 10 = 0.000233, 0.000211, and 0.000271 mg active ingredient (a.i.) cm −2 , LC 30 = 0.000413, 0.000398, and 0.000447 mg a.i. cm −2 , respectively), followed by etofenprox, and the mixture of acetamiprid with d‐tetramethrin and piperonyl butoxide (LC 10 = 0.00228 and 0.003267 mg a.i. cm −2 , LC 30 = 0.00437 and 0.01188 mg a.i. cm −2 , respectively). Deltamethrin and λ‐cyhalothrin negatively impacted adult walking behavior, increasing stop durations compared to controls. Adults exposed to LC 10 and LC 30 of λ‐cyhalothrin, and LC 30 of deltamethrin exhibited prolonged periods on their backs compared to the remaining treatments and the controls. The α‐cypermethrin LC 30 ‐exposed adults exhibited significantly shorter walking and stopping durations than controls but demonstrated prolonged climbing on the arena walls compared to adults exposed to the remaining a.i. and the control. A similar trend was observed for etofenprox. CONCLUSIONS Under sublethal concentrations, λ‐cyhalothrin and deltamethrin increased stop intervals and reduced the duration of climbing attempts of O. surinamensis versus α‐cypermethrin. These findings advance comprehension of the underexplored sublethal impacts of the tested a.i. on O. surinamensis adults, holding potential for leveraging insecticide‐induced behavioral effects to enhance warehouse pest management.