Pupal Size Distribution and Sexual Dimorphism in Wild and Laboratory Populations of Two Species of Anastrepha (Diptera: Tephritidae) Fruit Flies

Abstract

Body size is one of the most determining traits in the fitness of insects. For fruit fly (Diptera: Tephritidae) control programs using sterile insect technique, size is a valuable indicator of the quality of the mass-reared insects. However, laboratory colonization and mass-rearing conditions can contribute to the disparity in phenotypic traits between laboratory and wild populations, reducing the performance of sterile males and the effectiveness of the sterile insect technique. Hence the relevance of evaluating the possible variations in body size (size and shape) in 2 economically important species: Anastrepha ludens (Loew) and Anastrepha obliqua (Macquart) (both Diptera: Tephritidae). In this study, we compared pupal size distribution of wild and laboratory populations, using 3 parameters: pupal length, width, and weight. Additionally, we recorded the sex of the emerged adults to determine the sexual dimorphism related to pupae size. In A. ludens, male and female wild pupae were longer than pupae of their laboratory congeners, while laboratory pupae were wider and heavier than the wild pupae. In A. obliqua, male and female wild pupae were significantly larger than pupae of their laboratory congeners in all size parameters. We confirmed the sexual dimorphism in pupal size in both species and both populations. Females were bigger than males in all pupal size parameters. This study provides useful information about size distributions and dimorphism from pupal size, providing baseline data with potential implications and applications in mass rearing of A. ludens and A. obliqua for the application of the sterile insect technique.