Feeding on methoprene increases male accessory gland size and body protein in the Mexican fruit fly

Abstract

Methoprene, a juvenile hormone analog, accelerates male sexual maturation in some pest species controlled through the Sterile Insect Technique (SIT). The SIT consists of the mass-rearing, irradiation and release of insects into affected areas, where sterile males mate with wild females and render them infertile. Sterile males are held for 6 days in confinement before release, and they are often released before attaining sexual maturity. The use of methoprene during this time has been shown to increase male mating frequency. However, very little is known on the effects of methoprene on the reproductive physiology of tephritid pests, including male accessory gland size, whole body protein content, sperm transfer and female remating receptivity. Here we found that sterile Anastrepha ludens males fed methoprene with only a 1:24 protein to sugar diet had greater male mating frequency and bigger male accessory glands compared to males deprived of methoprene. Furthermore, positive effects of methoprene inclusion in the diet were found on the amount of sperm stored by females, and body protein content but only when males fed sugar only. Inclusion of methoprene in the diet did not affect remating propensity of wild females having mated with sterile males. Females mating with young 5-day-old males stored fewer sperm than females mating with older males regardless of diet. The use of methoprene as a pre-release supplement can positively impact early sexual maturation, energy reserves and male reproductive organs of A. ludens males, thus supporting its use in SIT programmes controlling this pest.