The sterile insect technique may be implemented to control populations of the oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae)

The sterile insect technique (SIT) is widely used to suppress or eradicate tephritid fruit fly pests that threaten agricultural crops. The SIT entails the production, sterilization, and release of large numbers of the target pest species, with the goal of achieving sterile male by wild female matings, which result in infertile eggs and the subsequent reduction of the wild pest population. The success of this control strategy depends, to a large extent, on the ability of released, sterile males to compete successfully against wild males to achieve copulations with wild females. Lance and McInnis (2005) proposed that species with greater male involvement in courtship and mating are less amenable to the SIT than species with simple courtship, because strong artificial selection characteristic of mass-rearing environments is more likely to generate greater behavioral modification to complex than simple courtship and thus to result in increased rejection by wild females. Consistent with Lance and McInnis (2005), the mating competitiveness of mass-reared males of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), a species with complex male courtship, is substantially lower than that of mass-reared males of the melon fly, Bactrocera cucurbitae (Coquillett), or the oriental fruit fly, Bactrocera dorsalis (Hendel), two species with very simple male courtship. In light of this difference in mating ability, we tested the prediction that higher overflooding ratios (sterile:wild males; OFR) would be required to control populations of C. capitata than of the Bactrocera spp. Levels of induced egg sterility achieved under different OFRs were compared to the “net sterility target,” computed as the proportional decrease in a species’ intrinsic birth rate (realized via SIT) required to balance the intrinsic rate of death and found to be ∼80% for the three species considered. Although the data are scant, they generally support the prediction. For B. cucurbitae, OFRs < 50:1 resulted in egg sterility levels near 80%, whereas in C. capitata similarly high sterility values were achieved only with OFRs >300:1. Likewise, relative to populations in control (untreated) sites, populations in release areas were reduced >99% at OFRs of 50:1–100:1 for B. cucurbitae in Japan compared to reductions for C. capitata of 50–93% at OFRs between 700:1–3,160:1 in Nicaragua and about 80% for OFRs between 100:1–400:1 in Hawaii. The implications of these findings for fruit fly SIT are discussed.

The genus Bactrocera (Diptera: Tephritidae) includes ≈70 polyphagous species that are major pests of fruit and vegetable crops. Most Bactrocera speci

Lek mating systems are relatively rare but occur in a diverse taxonomic array of animals, including birds, mammals, anurans, and insects. Such systems exhibit four features: 1) males provide no parental care and supply only gametes; 2) males are spatially aggregated at mating arenas (or leks); 3) males do not control access to resources critical to females; and 4) females are free to select mates at the arena. Among insects, fruit flies of the families Tephritidae and Drosophilidae display lek behavior that closely resembles the 'classic' lek mating systems of vertebrate species. The objective of this paper is to provide an overview of empirical findings on lek-forming tephritid and drosophilid flies. The essay is organized around a series of 19 questions, the first six of which provide background information on fruit fly leks. These questions deal with the location, persistence, and size of leks as well as pheromonal attraction of females and the nature of male-male aggression. The remaining questions touch on broader issues that are common to the study of lekking species regardless of taxonomic affiliation. For example, these questions concern skewed mating distributions among males, male signals important in female choice, the importance of male aggression and signaling position in affecting male mating success, the possibility of male choice, costs to males associated with lek displays, and evidence of direct and indirect benefits to females resulting from mate selection etc. Reflecting data availability, emphasis is on precopulatory mate choice, sperm competition and female cryptic choice are briefly addressed.