Mobility parameters of Tribolium castaneum and Rhyzopertha dominica populations with different susceptibility to phosphine

Phosphine (PH3) is the most commonly used fumigant to protect stored products from arthropod infestations worldwide. Our knowledge about the behavioral differences between phosphine-resistant and -susceptible stored product pest populations is limited. This study evaluated differences in mobility and behavior of populations of two major stored product insects, Tribolium castaneum (Herbst) and Rhyzopertha dominica (F.), which have different susceptibility to phosphine. In this regard, laboratory bioassays in Petri dish arenas were designed to determine if phosphine resistance has an impact on the walking and mobility behavior of adult beetles of both species. Results indicated that there were significant differences between resistant and susceptible populations for both species. Regarding velocity, R. dominica susceptible individuals moved faster than resistant ones. However, the resistant population showed reduced activity for several parameters tested compared to the susceptible population. Similar trends were also noted for T. castaneum. Knowledge of these parameters should be further utilized in management tactics, as resistant populations may behave in a different way in key management indicators such as trapping and sampling, as compared with susceptible ones. (C) 2020 Elsevier Ltd. All rights reserved.