Sex-linked differences in semiochemical-mediated movement by Trogoderma variabile Baillon and Trogoderma inclusum Le Conte (Coleoptera: Dermestidae) after exposure to long-lasting insecticide netting

Authors: RANABHAT, SABITA - Kansas State University; DOMINGUE, MICHAEL - US Department Of Agriculture (USDA); STOLL, IAN - University Of Missouri; BINGHAM, GEORGINA - University Of Nebraska; ZHU, KUN YAN - Kansas State University; Morrison, William - Rob

Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/6/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: Stored product insects are highly mobile and present in the landscape, and they may be able to readily disperse and find food sources by tracking food odors and insect pheromones. A recent new management tactic to reduce movement of dispersing insects is long-lasting insecticidal netting (LLIN) containing 0.4% deltamethrin. Two important and highly destructive dermestids in the US are warehouse beetle and larger cabinet beetle. However, it is unknown how exposure of adults to the deltamethrin-based insecticide netting may affect their ability to respond to food odors and pheromones. Using video-tracking, we found frequency of entering a space near food or pheromone increased 4–6-fold in single-sex populations of warehouse beetle after exposure to insecticide netting compared to untreated netting, while it was reduced in larger cabinet beetle. Overall, the movement parameters of adult larger cabinet beetle to odors were affected to a greater extent than that of warehouse beetle by exposure to long-lasting insecticide netting. Interestingly, there were sex-specific differences in the way insects responded to odors after exposure to insecticide netting. For example, larger cabinet beetle females moved 1.3-fold further compared to males and warehouse beetle males spent 5-fold more time near food and pheromone odors after insecticide exposure compared to females. Our results suggest that exposure to insecticide netting may differentially impact behavior of males and females and sex must be taken into account when planning and analyzing data from behavioral assays. Our research suggests the use of insecticide netting may complement other pest management tactics by altering the ability of stored product insects to find food and mates when used as part of a comprehensive integrated pest management program.

Technical Abstract: Stored product insects are highly mobile and present in the landscape, and they may be able to readily disperse by tracking plumes of food cues and pheromones. A recent novel preventative IPM tactic to intercept dispersing insects that has been successfully used after harvest is long-lasting insecticidal netting (LLIN) containing 0.4% deltamethrin. However, it is unknown how exposure to the deltamethrin-based LLIN (LLIN used thereafter) may affect olfaction and orientation to important semiochemicals by stored product insects. In this study, our aims were to evaluate whether exposure to LLIN affected male and female (or mixed sex) populations of Trogoderma variabile and T. inclusum movement in the presence of important semiochemicals, including food kairomones and pheromones. We evaluated this with a video-tracking protocol and confirmed volatile emissions with headspace collection coupled with gas chromatography and mass spectrometry (GC/MS). Movement was upregulated 4–6-fold in T. variabile after exposure to LLIN compared to control netting, while it was reduced by 28–54% in T. inclusum. Overall, the olfaction of adult T. inclusum was affected to a greater extent than that of T. variabile. There were sex-linked differences in olfaction after the insects were exposed to LLIN. Pheromonal stimuli were more important for males, but food and pheromones were equally important for females. Our research suggests the use of LLIN may enhance the effectiveness of other behaviorally-based strategies when used as part of a comprehensive IPM program.