Modeling long-term, stage-structured dynamics of Tribolium castaneum at food facilities with and without two types of long-lasting insecticide netting

Authors: RANABHAT, SABITA - Kansas State University; Gerken, Alison; Scheff, Deanna; ZHU, KUN YAN - Kansas State University; Morrison, William - Rob

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/16/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: The red flour beetle is a cosmopolitan and destructive pest at many food facilities. The use of long-lasting insecticide (LLIN) netting has shown incredible promise for the management of stored product insects. However, it is unknown how insecticide netting deployed within food facilities may affect the long-term population levels of red flour beetle compared to populations where no insecticide netting is present. Exposure to netting incorporated with two different insecticides (deltamethrin and alpha-cypermethrin) has been shown to affect mortality in the current generation and decrease offspring production in the subsequent generation; however, it is unknown how the use of this netting impacts subsequent generations and thus, long term population levels in food facilities. We modeled the long-term population levels of red flour beetle at food facilities over 15 generations by incorporating realistic estimates for mortality and offspring production after contact with both types of insecticide netting and comparing those estimates to estimates generated for population growth under scenarios in which no pest management tactics were deployed. We added parameters to the model with estimates from the literature and modeled the numbers of each life stage at each generation, including eggs, larvae, pupae, and adults. We found that deploying both insecticide nettings led to significant population reductions of 53–99%, whereas exponential population growth was predicted under scenarios in which no management tactics were used. In addition, there were differences in the frequencies of each life stage under each scenario modeled, with fewer eggs and larvae produced, and fewer periodic peaks in in population levels when insecticide netting was present compared to absent. Under realistic parametrization, populations of red flour beetle were predicted to go extinct (barring immigration of new individuals into the environment) in 15 generations. Our work contributes to a growing literature about the effectiveness of LLIN after harvest.

Technical Abstract: The red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), is a cosmopolitan and destructive external-infesting pest at many food facilities. The use of deltamethrin- and alpha-cypermethrin-incorporated long-lasting insecticide netting (LLIN) has shown incredible promise for the management of stored product insects. However, it is unknown how LLIN deployed within food facilities may affect the long-term population dynamics of T. castaneum compared to populations where no LLIN is present. Exposure to LLIN has been shown to affect mortality in the current generation and decrease progeny production in the subsequent generation. Thus, we modeled the long-term population dynamics of T. castaneum at food facilities over 15 generations by incorporating realistic estimates for mortality and progeny reduction after contact with LLIN compared to baseline growth by the species. We parameterized the model with estimates from the literature and used a four-stage structured population (eggs, larvae, pupae, and adults). The model was implemented using the package popbio in R. We found that deploying LLIN led to significant population reductions of 53–99% based on the estimates of mortality and progeny reduction from prior work, whereas the baseline model exhibited exponential population growth. In addition, there were differences in the frequencies of each life stage under each scenario modeled. As a result, it appears deploying LLIN may contribute to the local extirpation of T. castaneum within as few as 15 generations. Our work contributes to a growing literature about the effectiveness of LLIN after harvest.