Comparative capture of Trogoderma granarium and T. variabile in floor traps in single species releases with previously captured conspecific or heterospecific individuals

Authors: GOURGOUTA, MARINA - University Of Thessaly; BALIOTA, GEORGIA - University Of Thessaly; Morrison, William - Rob; DOMINGUE, MICHAEL - Animal And Plant Health Inspection Service (APHIS); ATHANASSIOU, CHRISTOS - University Of Thessaly

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/22/2021
Publication Date: 10/27/2021
Citation: Gourgouta, M., Baliota, G., Morrison Iii, W.R., Domingue, M.J., Athanassiou, C.G. 2021. Comparative capture of Trogoderma granarium and T. variabile in floor traps in single species releases with previously captured conspecific or heterospecific individuals. Journal of Economic Entomology. 114(6):2591-2597. https://doi.org/10.1093/jee/toab174.
DOI: https://doi.org/10.1093/jee/toab174

Interpretive Summary: An increasing amount of evidence suggests that traps for monitoring stored product insects may not be stably attractive over time. In fact, some prior work has suggested that the prior capture of certain species may affect the subsequent capture of future individuals of the same or different species. This may result as a function of odor signals emitted from dead or dying insects captured in traps. However, it is unknown how this phenomenon may affect monitoring of important quarantined species such as the khapra beetle, which has been rated as among the top 100 worst invasive species. Warehouse beetle is a closely related species to khapra beetle in the same genus, but not under quarantine conditions in the US. Both may commonly be intercepted at ports of entry in the US in monitoring programs. In seeding a commonly used commercial pitfall trap with a kairomone oil and either warehouse beetle or khapra beetle individuals, and then releasing the same or opposite species, we found that prior captures in traps did not negatively affect subsequent captures of either species. This is very promising news for monitoring protocols, suggesting that traps will not lose efficiency over time in the field as they potentially intercept individuals.

Technical Abstract: In the present work, a series of tests were performed to examine the effect of previously captured adults in floor traps, on the captures of 'rogoderma granarium and T. variabile, in single species releases. In a first series of tests, a single trap with kairomone oil and dead adults of single or both species, was placed in a plastic container, which was used as the release arena. Subsequently, adults of both species were separately released in the arena, and the adult capture was recorded 24 h later. In a second series of trials, two traps were placed in the same arena, containing different numbers of prior seeded adults, and adult capture was similarly recorded. For T. granarium, in all cases more adults were found inside the trap than under the trap or on the trap walls. In contrast, for T. variabile, most adults were recorded on the trap walls. In general, T. variabile had a stronger response to the traps than T. granarium. This work illustrates that previous captures of either species do not negatively affect captures of new live larvae and may tend to enhance captures in some cases. This has important implications for the use of traps for the biosureveillance of these two important dermestid species.