Intrinsic and synthetic stable isotope marking of tsetse flies

Rebecca Hood-Nowotny1§*, Margarete Watzka2b, Leo Mayr3c, Solomon Mekonnen1d, Berisha Kapitano4e and Andrew Parker1f

1Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency, Vienna, Austria
2Department of Chemical Ecology and Ecosystem Research, Vienna Ecology Centre, Faculty of Life Sciences - University of Vienna, Althanstrasse 14 ,A-1090 Vienna, Austria
3Kaliti Tsetse Mass Rearing and Irradiation Centre, Southern Tsetse Fly Eradication Project (STEP), Ministry of Science and Technology, Akaki Kaliti Kefle Ketema W.27 K.10, Debrezeyet Road, P.O. Box 7794, Addis Ababa, Ethiopia
4Southern Tsetse Eradication Project, Southern Regional Government Agricultural Bureau, P.O. Box 80, Awassa, Ethiopia
§Current address: Southern Tsetse Eradication Project, Ministry of Science and Technology, , P.O. Box 474, Hawassa, Ethiopia

Abstract

The sterile insect technique has been successfully used to eliminate tsetse populations in a number of programs. Program monitoring in the field relies on the ability to accurately differentiate released sterile insects from wild insects so that estimates can be made of the ratio of sterile males to wild males. Typically, released flies are marked with a dye, which is not always reliable. The difference in isotopic signatures between wild and factory–reared populations could be a reliable and intrinsic secondary marker to complement existing marking methods. Isotopic signatures are natural differences in stable isotope composition of organisms due to discrimination against the heavier isotopes during some biological processes. As the isotopic signature of an organism is mainly dependent on what it eats, by feeding factory–reared flies isotopically different diets to those of the wild population it is possible to intrinsically mark the flies. To test this approach unlabeled samples of Glossina pallidipes (Austen) (Diptera: Glossinidae) from a mass rearing facility and wild populations were analyzed to determine whether there were any natural differences in signatures that could be used as markers. In addition experiments were conducted in which the blood diet was supplemented with isotopically enriched compounds and the persistence of the marker in the offspring determined. There were distinct natural isotopic differences between factory reared and wild tsetse populations that could be reliably used as population markers. It was also possible to rear artificially isotopically labeled flies using simple technology and these flies were clearly distinguishable from wild populations with greater than 95% certainty after 85 days of “release”. These techniques could be readily adopted for use in SIT programs as complimentary marking techniques.

Keywords: Glossina pallidipes, Glossinidae, mass rearing, SIT, sterile insect technique

Abbreviations: AW-IPM, Areawide integrated pest management; SIT, Sterile insect technique; VPDB, Vienna Pee Dee Belemnite; VSMOW, Vienna Standard Mean Ocean Water

Correspondence: a* rebecca.clare.hood-nowotny@univie.ac.at, f a.parker@iaea.org, *Corresponding author

Editor: Tochi Dhadialla was editor of this paper.

Received: 14 May 2010 | Accepted: 25 February 2011 | Published: 1 July 2011

ISSN: 1536-2442 | Volume 11, Number 79

Hood-Nowotny R, Watzka M, Mayr L, Mekonnen S, Kapitano B, Parker A. 2011. Intrinsic and synthetic stable isotope marking of tsetse flies, using wing pigmentation. Journal of Insect Science 11:79 available online: insectscience.org/11.79


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