ARS | Publication request: Conditioned Microplitis Croceipes Cresson (Hymenoptera: Braconidae) Detect and Respond to 2,4-Dnt: Development of a Biological Sensor

Submitted to: Forensic Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 20, 2005
Publication Date: August 3, 2005
Citation: Tomberlin, J.K., Tertuliano, M., Rains, G., Lewis, W.J. 2005. Conditioned Microplitis croceipes Cresson (Hymenoptera: Braconidae) detect and respond to 2,4-DNT: Development of a biological sensor. Journal of Forensic Science. 50(5):1187-1190.

Interpretive Summary: Parasitic wasps optimize their ability to locate food and host insect resources by learning and subsequently using associated chemical and visual cues. ARS scientists at Tifton and the University of Georgia, together with other cooperators, are exploring whether the remarkable olfactory and learning abilities of these organisms can be harnessed for agricultural and military intelligence and detection purposes, such as monitoring for food safety concerns. The parasitic wasp, Microplitis croceipes, is capable of being trained to respond to target odors by allowing them to encounter the odor in association with food or hosts. The ability of this organism to learn, detect and respond to 2,4-DNT, a product associated with trinitrotoluene (TNT) was examined. Response behaviors of wasps trained to this compound were found to accurately reflect presence of the material as well as concentration levels. The demonstration of this capability of conditioned wasps advances the feasibility of this important detection and monitoring technology and accelerates it prospects for transfer into practical application.

Technical Abstract: Microplitis croceipes has served as a model for a number of studies investigating insect learning. Data from past studies have resulted in interest in possibly developing M. croceipes as a biological sensor to locate odors of human interest, such as narcotics and explosives. We examined the ability of M. croceipes to learn, detect, and respond to 2,4-DNT, which is a volatile discriminator of trinitrotoluene (TNT). The percentage of conditioned wasps to detect and respond to the various concentrations of 2,4-DNT for >15 sec was measured. Significantly more of the conditioned wasps responded to the concentration of 2,4-DNT used for conditioning than other concentrations examined. Accordingly, percent conditioned wasps to respond >15 sec could be used as a suitable measure to screen air samples and distinguish between samples with or without the target odorant. Furthermore, the data recorded in this study indicate the behavior being measured could possibly be used to estimate the concentration of the target odorant. Data in this study indicate M. croceipes can detect and respond to this compound, which provides further support for its possible development as a biological sensor. Such a sensor possibly could be used as a sentinel or portable system for detecting indicator odors of?(forensic?) (2,4-dinitrotoluene) importance.