Advances and Challenges of Using the Sterile Insect Technique for the Management of Pest Lepidoptera

Abstract

Over the past 30 years, the sterile insect technique (SIT) has become a regular component of area-wide integrated pest management (AW-IPM) programs against several major agricultural pests and vectors of severe diseases. The SIT-based programs have been especially successful against dipteran pests. However, the SIT applicability for controlling lepidopteran pests has been challenging, mainly due to their high resistance to the ionizing radiation that is used to induce sterility. Nevertheless, the results of extensive research and currently operating SIT programs show that most problems with the implementation of SIT against pest Lepidoptera have been successfully resolved. Here, we summarize the cytogenetic peculiarities of Lepidoptera that should be considered in the development and application of SIT for a particular pest species. We also discuss the high resistance of Lepidoptera to ionizing radiation, and present the principle of derived technology based on inherited sterility (IS). Furthermore, we present successful SIT/IS applications against five major lepidopteran pests, and summarize the results of research on the quality control of reared and released insects, which is of great importance for their field performance. In the light of new research findings, we also discuss options for the development of genetic sexing strains, which is a challenge to further improve the applicability of SIT/IS against selected lepidopteran pests.

Lessons from Drosophila: Engineering Genetic Sexing Strains with Temperature-Sensitive Lethality for Sterile Insect Technique Applications

“…The SIT strategy helps reduce the use of insecticides, which can have negative environmental consequences such as chemical pollution, kill non-target beneficial organisms and result in development of insecticide resistance in wild populations [ 4 , 5 ]. Although SIT has been successfully applied against the New World screwworm [ 6 ], various species of fruit flies [ 7 ], moth species [ 8 ], tsetse flies [ 9 ], and mosquitoes [ 9 , 10 ], there are opportunities for optimisation of existing SIT programs or expansion of SIT control programs to include additional insect pest species [ 11 , 12 ]. The logistics of mass-rearing invasive insect pests under factory conditions for intentional release are often complex and involve many factors including strain management to maintain genetic diversity, establishing suitable larval diet for large-scale rearing, sex separation as only males are required for SIT, then effective sterilization through radiation, marking, quality control (e.g., emergence rate and flight ability), handling and distribution to obtain high-quality, cost-effective sterile males [ 13 ].…”

“…A dominant conditional lethal mutation inserted directly onto the W, for example using the piggyBac transposon [ 65 ], or translocation of a dominant gene from the Z chromosome or autosome to the W, would be required to establish a sexing strain. The development of TSSs was initiated in the codling moth, Cydia pomonella , [ 66 ] but low efficiency of transgenesis in this species limited the research progress [ 8 ]. Several advantages of developing strains with dominant W chromosome conditional lethal temperature sensitive mutations include: (i) elimination of females using a restrictive temperature is inexpensive (ii) insect crosses could transfer the W chromosome (carrying the dominant allele) into a genetic background that best suited a particular country or region (iii) and the released sterile males will not carry transgenic constructs or factors associated with the sexing selecting process [ 66 ].…”

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“…The reduced fecundity and fertility of adults indicate that the disturbances in oogenesis and spermatogenesis, and on the other hand reduction in accessory gland secretions and number of eupyrene sperm (active sperm) will cause low fertility in insects [69]. Marec and Vreysen [70], suggested the reduced fertility resulting from chromosomal translocation. Wendell Snow, et al [71] report that sterilization significantly affects the type and quality of the sperm transferred by treated males.…”

Medium‐term feasibility of the management of the invasive crayfish Procambarus clarkii with the sterile males release technique

“…The SMRT is based on the release into the environment of sterile males able to compete with untreated reproductive males for mating partners. This technique has already been successfully applied to sterilise insects for integrated pest management 10 and is known as the sterile insect technique (SIT) 11 . The main parameter to achieve an optimal goal is the irradiating dose, which must be tightly tailored to ensure a high degree of sterility and low damage to somatic cells in order not to affect the reproductive behaviour of animals and ensure their competition for mating with wild‐type males.…”

“…The aspects to be taken into consideration for effective applicability of the SMRT are (i) the vitality of the males after irradiation, evaluating physiological and behavioural parameters, and (ii) the efficacy of the postirradiation damage of the testicular tissue that guarantees the effectiveness of the sterilization procedure. The dose needed for sterilization in arthropods can reach 300 Gy in the case of Lepidoptera 11 . Sterilization by radiation is already used in some commercial crustaceans, such as Penaeus japonicus , 12 Palaemonetes pugio , 13 and Macrobrachium rosenbergii , 14 with X‐ray doses ranging from 10 12 to 640 Gy 15 …”