Comparative rearing parameters for bisexual and genetic sexing strains of Zeugodacus cucurbitae and Bactrocera dorsalis (Diptera: Tephritidae) on an artificial diet

Authors: FEZZA, THOMAS - Animal And Plant Health Inspection Service (APHIS); Geib, Scott; SHELLY, TODD - Animal And Plant Health Inspection Service (APHIS)

Submitted to: Journal of Asia-Pacific Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/5/2018
Publication Date: 1/8/2018
Citation: Fezza, T.J., Geib, S.M., Shelly, T.E. 2018. Comparative rearing parameters for bisexual and genetic sexing strains of Zeugodacus cucurbitae and Bactrocera dorsalis (Diptera: Tephritidae) on an artificial diet. Journal of Asia-Pacific Entomology. 21:283-287. https://doi.org/10.1016/j.aspen.2018.01.007.

Interpretive Summary: The Sterile Insect Technique (SIT) is an important component of pest control strategies for suppressing populations of pest insects. This involves the release of large numbers of sterilized male individuals, which will mate with wild females, providing no viable offspring, thus suppressing the population. To have a good SIT system, the ability to rear and release male only individuals is important. An example of a male separation strain is a white pupae strain, where male pupae are brown and female pupae are white. Mechanical sorting of the pupae by color can allow for male only release. There could be fitness costs associated with harboring this trait, or others that allow for sex separation, which may impact the rearing output, or release quality of the insect. To test for this, rearing parameters were compared between the pupal color sexing and bisexual strains for both the oriental fruit fly and the melon fly. In both species, most of these parameters were significantly greater for the bisexual strain than the white pupal strains, and, for a given number of eggs, the production of flight-capable adults was approximately 2 times greater in the bisexual strains of both species. The potential usefulness of SIT against melon fly and oriental fruit fly is assessed based on these findings.

Technical Abstract: The Sterile Insect Technique (SIT) is an important component of area wide programs to control invading or established populations of pestiferous tephritids. The SIT involves the production, sterilization, and release of large numbers of the target species, with the goal of obtaining sterile male x wild female matings, which yield infertile eggs. A major advance in SIT involved sex-linked, genetic manipulations that allowed the production and release of male-only strains (also termed genetic sexing strains, GSS). The use of GSS avoids matings between sterile males and females, which may divert males from seeking and mating with wild females, and studies show that male-only releases result in greater suppression of wild populations than standard bisexual releases (i.e., those including both males and females). GSS based on sex-linked pupal color exist for Zeugodacus cucurbitae (Coquillett) and Bactrocera dorsalis (Hendel), two important agricultural pest species, but their rearing characteristics have not been documented in detail. The goal of the present study was to compare the pupal color sexing and bisexual strains for each of these species with respect to important rearing parameters, including egg production and eclosion of larvae from eggs (egg hatch), pupal recovery, and weight, emergence rate, and flight ability. In both species, most of these parameters were significantly greater for the bisexual strain than the GSS, and, for a given number of eggs, the production of flight-capable adults was approximately 2 times greater in the bisexual strains of both species. The potential usefulness of GSS in SIT against Z.cucurbitae and B.dorsalis is assessed based on these findings.