The Insect Pest Control Laboratory of the Joint FAO/IAEA Programme: Ten Years (2010-2020) of Research and Development, Achievements and Challenges in Support of the Sterile Insect Technique

Abstract

The Joint FAO/IAEA Centre (formerly called Division) of Nuclear Techniques in Food and Agriculture was established in 1964 and its accompanying laboratories in 1961. One of its subprograms deals with insect pest control, and has the mandate to develop and implement the sterile insect technique (SIT) for selected key insect pests, with the goal of reducing the use of insecticides, reducing animal and crop losses, protecting the environment, facilitating international trade in agricultural commodities and improving human health. Since its inception, the Insect Pest Control Laboratory (IPCL) (formerly named Entomology Unit) has been implementing research in relation to the development of the SIT package for insect pests of crops, livestock and human health. This paper provides a review of research carried out between 2010 and 2020 at the IPCL. Research on plant pests has focused on the development of genetic sexing strains, characterizing and assessing the performance of these strains (e.g., Ceratitis capitata), elucidation of the taxonomic status of several members of the Bactrocera dorsalis and Anastrepha fraterculus complexes, the use of microbiota as probiotics, genomics, supplements to improve the performance of the reared insects, and the development of the SIT package for fruit fly species such as Bactrocera oleae and Drosophila suzukii. Research on livestock pests has focused on colony maintenance and establishment, tsetse symbionts and pathogens, sex separation, morphology, sterile male quality, radiation biology, mating behavior and transportation and release systems. Research with human disease vectors has focused on the development of genetic sexing strains (Anopheles arabiensis, Aedes aegypti and Aedes albopictus), the development of a more cost-effective larvae and adult rearing system, assessing various aspects of radiation biology, characterizing symbionts and pathogens, studying mating behavior and the development of quality control procedures, and handling and release methods. During the review period, 13 coordinated research projects (CRPs) were completed and six are still being implemented. At the end of each CRP, the results were published in a special issue of a peer-reviewed journal. The review concludes with an overview of future challenges, such as the need to adhere to a phased conditional approach for the implementation of operational SIT programs, the need to make the SIT more cost effective, to respond with demand driven research to solve the problems faced by the operational SIT programs and the use of the SIT to address a multitude of exotic species that are being introduced, due to globalization, and established in areas where they could not survive before, due to climate change.

Keywords: area-wide integrated pest management; autocidal control; competitiveness; genetic sexing; genetics and molecular biology; human disease vectors; livestock bests; mass-rearing; plant pests; quality control; radiation.

Figure 1

Results of a model that shows the outcome of neglecting to suppress a small fraction of a pest population in an agroecosystem versus the effect of uniformly suppressing the entire pest population. Left: 10% of the population is untreated, and in four generations it produces a large number of individuals, while the 90% of the population that is treated declines. Right: Entire pest population in the agroecosystem is suppressed uniformly, and its numbers decline from generation to generation (Figure from Klassen and Vreysen, 2021, reproduced with permission).

Figure 2

Left: Brown pupae (males) and white pupae (females) from the Ceratitis capitata VIENNA 8 GSS. Right: Brown pupae (males) and black pupae (females) from the Anastrepha ludens Tapachula 7 GSS (Photocredit: C. Caceres).

Figure 3

Walk in field cage for insect sexual behavior studies. (Photocredit: C. de Beer).

Figure 4

The tsetse fly and its associated microorganisms. Figure adapted with permission from [116,117].

Figure 5

(A) Dissected adult Glossina pallidipes showing Hypertrophy Salivary Gland (HSG) symptoms caused by the Glossina pallidipes salivary gland hypertrophy virus (GpSGHV), (B) Normal salivary gland (BGS) relative to the adults tsetse head, (C) Transmission electron microscopy (TEM) micrograph of GpSGHV virus particles.

Figure 6

Effect of hypoxia during irradiation in Aedes albopictus. Hypoxia has significant protective effects, rendering irradiated males with lower sterility levels at all doses (p = 1.48 × 10⁻⁵) Figure from Yamada et al., 2020 [282].

Figure 7

Fertility of female Ae. albopictus mated once with an untreated or sterilized male, or twice at various interval of time with males in untreated-sterilized or sterilized-untreated mating sequences. Individual fertility of females over multiple gonotrophic cycles [305].

Figure 8

Flight ability test conducted on sterile male Anopheles arabiensis (Source: (Culbert et al. [314])) (Photo credit: H. Maiga).

Figure 9

Schematic representation of the phased conditional approach (PCA) proposed to apply SIT and Location of the pilot sites in each phase. (A) The pyramid shows the amount of innovation related to operational research that is required in each phase, whereas the volume of activities and investment will generally grow in the opposite way. (B) Locations of field sites implementing the SIT against mosquitoes, some of which in combination with the incompatible insect technique (IIT-SIT). The number of field trials for each strategy are presented in brackets. Phase 0 sites are not included. (Source: modified from (Bouyer et al. [319])).