Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2018 Dec 24;11(Suppl 2):657.
doi: 10.1186/s13071-018-3214-9.

Combined sterile insect technique and incompatible insect technique: sex separation and quality of sterile Aedes aegypti male mosquitoes released in a pilot population suppression trial in Thailand

Patttamaporn Kittayapong  1   2 , Nuanla-Ong Kaeothaisong  3 , Suwannapa Ninphanomchai  3 , Wanitch Limohpasmanee  4
Affiliations

Combined sterile insect technique and incompatible insect technique: sex separation and quality of sterile Aedes aegypti male mosquitoes released in a pilot population suppression trial in Thailand

Patttamaporn Kittayapong et al. Parasit Vectors. .

Abstract

Background: The sterile insect technique (SIT), which is based on irradiation-induced sterility, and incompatible insect technique (IIT), which is based on Wolbachia-induced cytoplasmic incompatibility (a kind of male sterility), have been used as alternative methods to reduce mosquito vector populations. Both methods require the release of males to reduce fertile females and suppress the number of natural populations. Different techniques of sex separation to obtain only males have been investigated previously. Our work involves an application of mechanical larval-pupal glass separators to separate Wolbachia-infected Aedes aegypti males from females at the pupal stage, prior to irradiation, and for use in a pilot field release and to assess the quality of males and females before and after sex separation and sterilization.

Results: This study was the first to demonstrate the efficiency of mechanical glass separators in separating males for use in an Ae. aegypti suppression trial by a combined SIT/IIT approach. Our results indicated that male and female pupae of Wolbachia-infected Ae. aegypti mosquitoes were significantly different (p < 0.05) in weight, size, and emergence-time, which made it easier for sex separation by this mechanical method. During the pilot field release, the percentage of female contamination was detected to be quite low and significantly different between the first (0.10 ± 0.13) and the second (0.02 ± 0.02) twelve-week period. Both males and females were almost completely sterile after exposure to 70 Gy irradiation dose. We observed that both irradiated Wolbachia-infected males and females survived and lived longer than two weeks, but males could live longer than females (p < 0.05) when they were irradiated at the same irradiation dose. When comparing irradiated mosquitoes with non-irradiated ones, there was no significant difference in longevity and survival-rate between those males, but non-irradiated females lived longer than irradiated ones (p < 0.05).

Conclusion: Mechanical sex separation by using a larval-pupal glass separator was practically applied to obtain only males for further sterilization and open field release in a pilot population suppression trial of Ae. aegypti in Thailand. Female contamination was detected to be quite low, and skilled personnel can reduce the risk for female release. The irradiated Wolbachia-infected females accidentally released were found to be completely sterile, with shorter life span than males.

Keywords: IIT; Longevity; Mosquito vector; Pupal size; SIT; Sterility; Wolbachia.

PubMed Disclaimer

Conflict of interest statement

Ethics approval and consent to participate

The pilot suppression trial of Aedes aegypti using a combined sterile insect technique and Wolbachia-based approach was reviewed and approved by Mahidol University Institutional Review Board (MU-CIRB 2016/085.0407).

Consent for publication

Not applicable.

Competing interests

The authors declare that they have no competing interests.

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Figures

Fig. 1
Fig. 1
Percentage of female contamination after mechanically sex separated to obtain sterile males for use in the pilot open field release, in order to suppress natural Aedes aegypti populations
Fig. 2
Fig. 2
Total number of eggs and egg hatch rate from mating between irradiated Wolbachia-infected males and non-irradiated Wolbachia-infected females of Aedes aegypti mosquitoes
Fig. 3
Fig. 3
Mean longevity and survival rate of non-irradiated and irradiated Wolbachia-infected Aedes aegypti male and female mosquitoes, after being sex-separated by using larval-pupal glass separators
See this image and copyright information in PMC

References

    1. Lees RS, Gilles JRL, Hendrichs J, Vreysen MJB, Bourtzis K. Back to the future: the sterile insect technique against mosquito disease vectors. Opin Insect Sci. 2015;10:156–162. doi: 10.1016/j.cois.2015.05.011. - DOI - PubMed
    1. Saridaki A, Bourtzis K. Wolbachia: More than just a bug in insects genitals. Curr Opin Microbiol. 2010;13(1):67–72. doi: 10.1016/j.mib.2009.11.005. - DOI - PubMed
    1. Nikolouli K, Colinet H, Renault D, Enriquez T, Mouton L, Gibert P. Sterile insect technique and Wolbachia symbiosis as potential tools for the control of the invasive species Drosophila suzukii. J Pest Sci. 2018;91(2):489–503. doi: 10.1007/s10340-017-0944-y. - DOI - PMC - PubMed
    1. Bourtzis K, Robinson AS. Insect pest control using Wolbachia and radiation. In: Bourtzis K, Miller T, editors. Insect Symbiosis 2. Boca Raton, FL, USA: Taylor and Francis, CRC Press; 2006. pp. 225–246.
    1. Bourtzis K, Dobson SL, Xi Z, Rasgon JL, Calvitti M, Moreira LA, et al. Harnessing mosquito-Wolbachia symbiosis for vector and disease control. Acta Trop. 2014;132:S150–S163. doi: 10.1016/j.actatropica.2013.11.004. - DOI - PubMed

LinkOut - more resources