Combined Effects of Methoprene and Metformin on Reproduction, Longevity, and Stress Resistance in Anastrepha ludens (Diptera: Tephritidae): Implications for the Sterile Insect Technique

Survival and mating success are traits of quality in mass-reared sterile males. Thus, studying the trade-offs between these traits may help to improve process in the sterile insect technique (SIT). Here, we tested the hypothesis that modifying individual metabolism, especially of energetic reserves, may reduce the negative impact of an early reproduction on the survival of Anastrepha ludens flies. Appling metformin (a drug used to treat type II diabetes) that improves insects' survival, through dietary restriction mimicry, and methoprene (a juvenile hormone analogue) that accelerates the age to reproduction in insects, we explore the dynamic of this trade-off. We fed A. ludens flies with metformin, methoprene, or a mixture of metformin-methoprene for five consecutive days. We determined the effect of these treatments on the fecundity and fertility (number of eggs and percentage of hatching) of females, on sexual maturation and mating success of males, and on the survival of both sexes. The results showed that the acceleration in sexual maturation by the action of methoprene significantly reduced survival in both sexes of two different fly strains. However, adding metformin to the diet buffered this negative effect, without reducing the mating propensity compared with the males treated only with methoprene. The response to metformin was sex-specific since females responded to high doses of the substance, whereas males responded better to low doses. These results suggest that trade-offs between survival and reproduction do not necessarily depend on energy reserves but they are intrinsically related to metabolic regulation and hormonal control.