Abstract
BackgroundThe New World screwworm, Cochliomyia hominivorax, is a devastating pest of livestock endemic to subtropical and tropical regions of the Western hemisphere. The larvae of this species feed on the tissue of living animals, including man, and can cause death if untreated. Over 60 years ago, the sterile insect technique (SIT) was developed with the aim of eradicating this pest, initially from Florida but subsequently from all of North and Central America. From the outset it was appreciated that SIT would be more efficient if only sterile males were released in the field, but this was not possible until now.ResultsHere, we report on the development and evaluation of the first sexing strains of C. hominivorax that produce only males when raised on diet without tetracycline. Transgenic lines have been developed that possess a tetracycline repressible female-lethal genetic system. Ten of these lines show high female lethality at the late larval/pupal stages and three of them present dominant female lethality. Most of the lines were comparable to the wild type parental strain in several fitness parameters that are relevant to mass rearing in a production facility. Further, three lines performed well in male mating success and male competition assays, suggesting they would be sexually competitive in the field. Consequently, one transgenic line has been selected by the New World Screwworm Program for evaluation under mass rearing conditions.ConclusionsWe conclude that the promising characteristics of the selected sexing strains may contribute to reduce production costs for the existing eradication program and provide more efficient population suppression, which should make a genetic control program more economical in regions were C. hominivorax remains endemic.Electronic supplementary materialThe online version of this article (doi:10.1186/s12915-016-0296-8) contains supplementary material, which is available to authorized users.
Highlights
The New World screwworm, Cochliomyia hominivorax, is a devastating pest of livestock endemic to subtropical and tropical regions of the Western hemisphere
In transgenic L. cuprina, both FL11 and FL12 are functional [11], but it is possible that the longer promoter in FL12 may have a higher basal activity at the temperatures that are used to rear C. hominivorax larvae (37–40 °C)
In FL12, the tTA gene cassette was inserted into a piggyBac vector that contained the ZsGreen marker driven by the strong constitutive Lchsp83 gene promoter and in FL11 it was inserted into a piggyBac vector containing the Lchsp83-DsRed express 2 marker
Summary
The New World screwworm, Cochliomyia hominivorax, is a devastating pest of livestock endemic to subtropical and tropical regions of the Western hemisphere. The New World screwworm, Cochliomyia hominivorax, is an insect pest that parasitizes warm-blooded animals in tropical and subtropical regions of the Western hemisphere Females lay their eggs, often near wounds, on the animal’s skin and after the larvae hatch, they feed on the animals’ live tissues, enlarging the wound, which can cause death [5]. Often near wounds, on the animal’s skin and after the larvae hatch, they feed on the animals’ live tissues, enlarging the wound, which can cause death [5] This insect was responsible for the loss of hundreds of millions of dollars annually to the livestock industry of several countries and great efforts were made to control it [5]. The Comisión Panamá–Estados Unidos para la Erradicación y Prevención del Gusano Barrenador del Ganado (COPEG) operates a biosecure facility dedicated to the mass rearing, sterilization, and dispersal of millions of sterile insects every week in the barrier zone between Panama and Colombia, preventing the re-introduction of screwworms from South America, where it still plagues all warm-blooded animals
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