Mobility of Adult Tribolium castaneum (Coleoptera: Tenebrionidae) and Rhyzopertha dominica (Coleoptera: Bostrichidae) After Exposure to Long-Lasting Insecticide-Incorporated Netting

Abstract

Stored products represent an enormous economic output, but insects regularly immigrate into stored products from the surrounding landscape throughout the postharvest supply chain. Long-lasting insecticide-incorporatednetting (LLIN), which usually contains an incorporated pyrethroid, has been used as part of a strategy to reduce the spread of malaria in tropical regions since the 1990s and has only recently been considered for its application in pre- and postharvest agricultural contexts. The goal of this study was to determine how short-term exposure to LLINs in the laboratory impacts the locomotory behavior and mortality for adult Tribolium castaneum (Herbst), (Coleoptera: Tenebrionidae) red flour beetle, and Rhyzopertha dominica (Fauvel), (Coleoptera: Bostrichidae) lesser grain borer, at different periods of time after exposure. Exposure to LLINs resulted in multiple-fold reductions in the distance moved and elevated angular velocity in both species that quickly took effect and persisted even after 168 h compared with adults exposed to control netting. R. dominica was somewhat more susceptible than T. castaneum to LLINs. Finally, the dispersal capacity of both species, measured as ability to move to a remote resource patch, was significantly impaired or absent after exposure to LLINs compared to adults exposed to control netting. Our results demonstrate that LLINs are a promising new technology for reducing infestation by stored product insects since even short exposures limit movement and ultimately lead to knockdown and death.

Mobility of Stored Product Beetles after Exposure to a Combination Insecticide Containing Deltamethrin, Methoprene, and a Piperonyl Butoxide Synergist Depends on Species, Concentration, and Exposure Time

“…However, for each species, there were substantial reductions in movement even at exposure to low concentrations of the insecticide. This suggests that dispersal from the treated area will be minimal, and these individuals will likely not be able to colonize new areas of a food facility (e.g., including perhaps adjacent grain bins), as has been documented by exposure of T. castaneum and R. dominica to a long-lasting, deltamethrin-incorporated netting material [16]. Understanding movement after exposure provides a more comprehensive picture of the efficacy for chemical control tactics, with clear management implications.…”

“…One adult from each concentration was placed individually into six filter paper-lined (Whatman #1, GE Healthcare, Chicago, IL, USA) 62 cm 2 Petri dishes, where movement (distance moved and instantaneous velocity) was recorded using a video-tracking apparatus combined with Ethovision XT v. 14.0 (Noldus Software, Leesburg, VA, USA). The apparatus was described in detail in Morrison et al [16] Briefly, a network camera (Basler AG, Ahrensburg, Germany) suspended 80 cm above the insects recorded the movement of each adult for 10 min, after which the dishes were removed, and the insects were discarded. This process was repeated four more times per replicate, with a total of n = 15 insects tested per treatment combination.…”

“…Guedes et al [15] and Morrison et al [16] used Ethovision ® , a system that is designed to continuously monitor movement of an individual insect on a target area or surface. The time to knockdown of adults, and immobilization patterns during or after exposure, have been used as indicators of insecticidal efficacy and the presence of phosphine resistance [17,18].…”

“…Understanding the range of indirect toxicity effects on the behavior of insects may help to provide food facility managers with a more comprehensive assessment of the efficacy by chemical control measures [15]. Furthermore, the effects on mobility may be used to predict mortality and concomitant efficacy [15,16].…”

A Review of the Phenotypic Traits Associated with Insect Dispersal Polymorphism, and Experimental Designs for Sorting out Resident and Disperser Phenotypes

“…By using these two types of hostile matrix, these authors found that: (a) A higher angle of the connecting tube, i.e., a more difficult dispersal path, lowered the dispersal success of males and females of T. castaneum, and (b) the increased length of the tubes connecting the containers increased the duration necessary for reaching the terminal (destination) container. Morrison et al [79] modified the Arnold's et al [72] system by working with two containers whose distance was increased (25, 75, and 175 cm) in order to investigate the effects of short exposures to pyrethroid (long-lasting insecticide-incorporated netting) on the dispersal capabilities of two insect species. For control insects, the matrix was slightly hostile for the red flour beetle, with fewer insects reaching the destination containers when the distance in between the two containers was the highest (175 cm), as compared with the two other tested distances.…”