Dangerous liaisons of three key secondary stored-product pests in cracked maize

Abstract

The current study examines the relationships of Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae) with Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) and Tenebrio molitor L. (Coleoptera: Tenebrionidae) through Gaussian and Poisson regression models on cracked maize. For this purpose, variable temperatures (25 °C, 30 °C, and 35 °C), relative humidities (RH) (55% and 75%), exposure intervals (65 days, 130 days, and 195 days), and insect combinations (the insect species alone and the combinations per 2 or 3 species that included O. surinamensis) were utilized. Poisson model was the most suitable for the response insects alive while Gaussian model for the weight loss. The increase of temperature from 25 °C to 30 °C and from 30 °C to 35 °C led to a gradual decrease of insects alive and a gradual increase of weight loss, while the enhancement of RH caused increase of both responses. At the 195 days of storage period, insects alive reduced whereas weight loss amplified. The combinations of insects that led to the highest and the lowest numbers of insects alive were O. surinamensis alone and T. molitor alone respectively. The most damaging combination was O. surinamensis-T. molitor while the least damaging was T. molitor alone. Findings of the current study enrich the existing knowledge of the relationships of three secondary stored-product insects in processed maize. The complexity of their coexistence is linked with the forecast of the contingent damage of the insect activity during the storage period.