A comparison of anesthesia techniques for entomological experimentation: Longevity of the leaf-mining fly pest Scaptomyza flava Fallén (Drosophilidae)

Historically, handling insects usually involved their being killed as early studies used these organisms for work on genetics, physiology and/or pesticide bioassays. With the advancement of these research topics, the development of behavioral studies and the sensitivity of culturally important, threatened or endangered species, approaches that focus on non-lethal preparation of the insects for experimentation have become important. Anesthesia has been used as one of these non-lethal approaches to provide researchers flexibility when designing experiments. Two common anesthetics used for insect experimentation are carbon dioxide and chilling. These anesthetics have been used frequently in the literature but their sub-lethal effects on insects are poorly studied. Another that has potential for experimental use is triethylamine (TEA). This chemical shows promise because of its ease of use and potency as an insect anesthetic, but evidence, if any, of the sub-lethal effects is almost non-existent in the literature. A series of experiments was carried out to find the optimal exposure times and/or concentrations for each of these three approaches. Once an optimal treatment was found for each approach, these were compared to each other in a subsequent experiment. It was found that TEA is a far superior anesthetic when recording/observing fly longevity.