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

Bio-Protection Research Centre, Lincoln University, Lincoln, New Zealand
DOI
10.7287/peerj.preprints.2874v1
Subject Areas
Anesthesiology and Pain Management, Entomology, Toxicology
Keywords
Anesthesia, Chilling, Scaptomyza flava, Triethlyamine, Brassicaceae, Leaf-miner, Drosophilidae, CO2
Copyright
© 2017 Rayl et al.
Licence
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
Cite this article
Rayl R, Wratten S. 2017. A comparison of anesthesia techniques for entomological experimentation: Longevity of the leaf-mining fly pest Scaptomyza flava Fallén (Drosophilidae) PeerJ Preprints 5:e2874v1

Abstract

Historically, handling insects has usually involved their being killed, but non-lethal approaches are necessary when evaluating the biology of such organisms. Anesthesia has been used as one of these non-lethal approaches. Two common anesthetics used in this way have been carbon dioxide and chilling. These have been used frequently in the literature but have sub-lethal effects on insects that may affect further experimentation. An alternative anesthetic that has potential for experimental use is triethylamine (TEA). This 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. Here, longevity was use as a proxy for fitness as this is a common approach to laboratory work of this type for pests and their natural enemies. A series of experiments were carried out to find the optimal rates for these three selected anesthetics. The organism selected for this work was the fly Scaptomyza flava (Fallén), the larvae of which mine the leaves of commercial brassica crops worldwide. It is a ‘cosmetic’ pest in that damage thresholds for crop rejection are very low and prophylactic use of insecticides is the norm. One way of mitigating the negative environmental aspects of this approach is to enhance biological control. One such way of enhancing biological control is the use of flowering plants, as they can provide alternative resources to natural enemies, which can enhance their ability to control pests. To evaluate these flowering plants, handling of the insects is necessary and anesthesia is used for this purpose. For each anesthetic an optimal rate was found, then these rates were compared to each other in a subsequent experiment. These anesthetics differed markedly in their value in terms of the duration of the anesthesia and other practical considerations. TEA had the longest effect, CO2 and chilling had the shortest. All three were similar in their effects on longevity (i.e. recovery time and mortality rates).

Author Comment

This is a submission to PeerJ for review.

Supplemental Information

Rscript for chilling recovery and deaths

DOI: 10.7287/peerj.preprints.2874v1/supp-1

Rscript for TEA recovery of all treatments

DOI: 10.7287/peerj.preprints.2874v1/supp-3

Rscript for CO2 recovery and deaths

DOI: 10.7287/peerj.preprints.2874v1/supp-4

Rscript TEA 25% for recovery

DOI: 10.7287/peerj.preprints.2874v1/supp-5

Rscript TEA 75% for recovery

DOI: 10.7287/peerj.preprints.2874v1/supp-6

Rscript TEA 100% for recovery

DOI: 10.7287/peerj.preprints.2874v1/supp-7

Rscript for the Group 2 experiments for deaths

DOI: 10.7287/peerj.preprints.2874v1/supp-8

Rscript for the Group 2 recovery

DOI: 10.7287/peerj.preprints.2874v1/supp-9

Rscript TEA 50% for recovery

DOI: 10.7287/peerj.preprints.2874v1/supp-11

Chilling recovery and deaths data table

DOI: 10.7287/peerj.preprints.2874v1/supp-12

CO2 recovery and deaths table

DOI: 10.7287/peerj.preprints.2874v1/supp-13