title: A transgenic male-only strain of the New World screwworm for an improved control program using the sterile insect technique.
abstract: The 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.
  
  
  
  Here, 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.
  
  
  
  We 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.
authors: Department of Entomology, North Carolina State University, Campus Box 7613, Raleigh, NC, 27695-7613, USA.|Panama-United States Commission for the Eradication and Prevention of Screwworm (COPEG), Pacora, Panama.|Smithsonian Tropical Research Institute, Naos Molecular Laboratory, Panama City, Panama.
authors: Carolina
authors: C
authors: Concha
authors: USDA-ARS, Tick and Biting Fly Research Unit, Knipling-Bushland Livestock Insects Research Laboratory, 2700 Fredericksburg Rd., Kerrville, TX, 78028, USA.|Present address: Department of Veterinary Parasitology, Madras Veterinary College, Tamil Nadu Veterinary and Animal Sciences University, Chennai, India.
authors: Azhahianambi
authors: A
authors: Palavesam
authors: USDA-ARS, Tick and Biting Fly Research Unit, Knipling-Bushland Livestock Insects Research Laboratory, 2700 Fredericksburg Rd., Kerrville, TX, 78028, USA.
authors: Felix D
authors: FD
authors: Guerrero
authors: USDA-ARS, Screwworm Research Unit, Pacora, Panama.
authors: Agustin
authors: A
authors: Sagel
authors: Department of Entomology, North Carolina State University, Campus Box 7613, Raleigh, NC, 27695-7613, USA.
authors: Fang
authors: F
authors: Li
authors: Department of Statistics, North Carolina State University, Campus Box 8203, Raleigh, NC, 27695-8203, USA.
authors: Jason A
authors: JA
authors: Osborne
authors: Panama-United States Commission for the Eradication and Prevention of Screwworm (COPEG), Pacora, Panama.
authors: Yillian
authors: Y
authors: Hernandez
authors: USDA-ARS, Screwworm Research Unit, Pacora, Panama.
authors: Trinidad
authors: T
authors: Pardo
authors: USDA-ARS, Screwworm Research Unit, Pacora, Panama.
authors: Gladys
authors: G
authors: Quintero
authors: USDA-ARS, Screwworm Research Unit, Pacora, Panama.
authors: Mario
authors: M
authors: Vasquez
authors: USDA-APHIS-IS, Pacora, Panama.
authors: Gwen P
authors: GP
authors: Keller
authors: USDA-ARS, Screwworm Research Unit, Pacora, Panama.|USDA-ARS, Screwworm Research Unit, Knipling-Bushland Livestock Insects Research Laboratory, 2700 Fredericksburg Rd., Kerrville, TX, 78028, USA.
authors: Pamela L
authors: PL
authors: Phillips
authors: USDA-APHIS, IS Action Programs, 2881 F&B Road, College Station, TX, 77845, USA.
authors: John B
authors: JB
authors: Welch
authors: Smithsonian Tropical Research Institute, Naos Molecular Laboratory, Panama City, Panama.
authors: W Owen
authors: WO
authors: McMillan
authors: USDA-ARS, Screwworm Research Unit, Pacora, Panama.|USDA-ARS, Screwworm Research Unit, Knipling-Bushland Livestock Insects Research Laboratory, 2700 Fredericksburg Rd., Kerrville, TX, 78028, USA.
authors: Steven R
authors: SR
authors: Skoda
authors: Department of Entomology, North Carolina State University, Campus Box 7613, Raleigh, NC, 27695-7613, USA. mjscott3@ncsu.edu.
authors: Maxwell J
authors: 0000-0001-6536-4735
authors: MJ
authors: Scott
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D004175:Diptera / Q000187:drug effects / Q000235:genetics*; D005260:Female; D008297:Male; D010572:Pest Control, Biological / Q000379:methods*; D018570:Risk Assessment; D012726:Sexual Behavior, Animal / Q000187:drug effects; D013242:Sterilization; D013752:Tetracycline / Q000494:pharmacology
chemical_list: D013752:Tetracycline
keywords: Genetic control; Male-only; New World screwworm; Sterile insect technique; Transformer; tTA