Bi-environmental cage for colony management in the mass rearing of Anastrepha ludens (Diptera: Tephritidae).

Abstract

Anastrepha ludens (Loew) is controlled in Mexico using sterile insect technique (SIT). SIT relies primarily on mass-reared insects, which are subjected to the effects of selection during colonization and rearing, and that frequently result in modifications of their biology and behavior. Here, we propose and evaluate a novel "bi-environmental cage" for colony management which promotes more natural sexual selection. The cage allows each sex to reach sexual maturity in separate compartments acclimatized according to natural conditions. Females mature in areas where they can recognize oviposition sites, while males mature in areas populated with small trees to allow establishment of territories in leks and performance of courtship behaviors. To determine whether the bi-environmental cage can minimize the potential adverse effects on mating competitiveness, two strains of A. ludens were tested; wild flies strain and genetic sexing strain Tapachula 7 (mass-reared flies). We found that after 4 generations in the mass-reared flies in the bi-environmental cage showed a level of fecundity similar to that of flies from the conventional cage. A similar pattern was also seen in the case of wild flies in both types of cages. In addition, other biological attributes of the wild strain assessed over six generations showed adaptability to mass-rearing conditions. Wild males from the bi-environmental cages were more sexually competitive than those from the conventional cage. Our results show that it is possible to mitigate many of the detrimental effects of domestication on the sexual performance of mass-reared males by using close-to-natural conditions for colony management.