Anopheles arabiensis egg treatment with dieldrin for sex separation leaves residues in male adult mosquitoes that can bioaccumulate in goldfish (Carassius auratus auratus)

Abstract

The sterile insect technique (SIT) is a biological control tactic that is used as a component of area-wide integrated pest management (AW-IPM) programs. The SIT can only be applied against disease-transmitting mosquitoes when only sterile male mosquitoes are released, and the blood-sucking and potentially disease-transmitting females are eliminated from the production line. For Anopheles arabiensis, a potent vector of malaria, a genetic sexing strain was developed whereby females can be eliminated by treating the eggs or larvae with the insecticide dieldrin. To evaluate the presence of dieldrin residues in male mosquitoes designated for SIT releases, a simple, sensitive, and accurate gas chromatography–electron capture detector (GC–ECD) method was developed. In addition, bioaccumulation and food chain transfer of these residues to fish after feeding with treated mosquitoes was demonstrated. The overall recovery from method validation studies was 77.3 ± 2.2% (mean ± relative standard deviation [RSD]) for the mosquitoes, and 99.1 ± 4.4% (mean ± RSD) for the fish. The average dieldrin concentration found in adult male An. arabiensis was 28.1 ± 2.9 µg/kg (mean ± standard deviation [SD]). A range of 23.9 ± 1.1 µg/kg to 73.9 ± 5.2 µg/kg (mean ± SD) of dieldrin was found in the fish samples. These findings indicate the need to reassess the environmental and health implications of control operations with a SIT component against An. arabiensis that involves using persistent organochlorines in the sexing process.

Construction of a genetic sexing strain for Aedes albopictus: a promising tool for the development of sterilizing insect control strategies targeting the tiger mosquito

“…Larvae or even eggs [24] should be treated exclusively in the laboratory for sexing purposes. However, traces of dieldrin may persist in adults as previously reported in Anopheles arabiensis GSS [25]. Although the overall amount of dieldrin residues remaining in the mosquito body has been overestimated in previous studies [25], their main conclusions remain valid: sterile males released in the frame of SIT or other population suppression projects using rdl-based GSS would still carry dieldrin residues which can bio-accumulate in the environment and contribute to the increasingly worrying phenomena of insecticide resistance.…”

Development of a genetic sexing strain of Anopheles arabiensis for KwaZulu‐Natal, South Africa

“…This GSS strain has been evaluated for reliability in female elimination, radiation sensitivity and mating competitiveness (Oliva et al ., ; Yamada et al ., ) and shows potential as a candidate for use in a SIT programme. The greatest challenges facing this strain are environmental concerns, stability and productivity concerns associated with its use (Yamada et al ., , ; G. Munhenga, unpublished data). Furthermore, this strain cannot be directly transferred for SIT releases under a different country setting because it contains an exclusively Sudanese genetic background.…”

Sex Sorting for Pest Control: It’s Raining Men!

“…arabiensis strain in which the dieldrin-resistance allele was translocated to the Y chromosome so that males are resistant to dieldrin and females susceptible [64]. This strain presents low productivity, male recovery being 13% of the initial number of eggs [65][66][67] with a risk that released males spread highly toxic dieldrin into the environment [68]. However, this strain has been backcrossed into different An.…”