Effects of the juvenile hormone analogue methoprene and dietary protein on male melon fly Bactrocera cucurbitae (Diptera: Tephritidae) mating success

The effect of access to dietary protein (P) and the topical application of a juvenile hormone analogue (methoprene (M)) on mating behaviour of male melon fly Bactrocera cucurbitae was assessed in the laboratory and in field cages. Age, dietary protein and methoprene application increased the mating success and influenced the mating behaviour. Treatment with methoprene (M+) to protein-deprived (P−) males had only a modest effect on the acceleration of sexual maturity, but application of methoprene (M+) to protein-fed (P+) males greatly accelerated sexual maturity. Protein diet (P+) increased mating success of males in comparison to protein-deprived (P−) males. Protein and methoprene have a synergistic effect on mating behaviour, since M + P+ treated males exhibit reduced mating latency and achieved higher mating in younger ages than methoprene and/or protein-deprived males. Copulation duration was correlated with nutritional status and M + P+ males copulated longer at the age of advanced sexual maturity than M − P+ males. Our results suggest that in this species with a lek mating system, females discriminate between the males based on their sexual signals, which were influenced by protein in the adult diet, methoprene application and age. The results are discussed in the light of mating competitiveness of precocious treated young males and their relevance to Sterile Insect Technique application against this pest species.