Sexual maturity and intraspecific mating success of two sibling species of the Bactrocera dorsalis complex



Bactrocera carambolae Drew & Hancock and B. papayae Drew & Hancock (Diptera: Tephritidae), two closely related sibling species in the B. dorsalis (Hendel) complex were shown to have different rates of sexual maturity. The response of B. carambolae males to methyl eugenol was observed to begin 10 days after emergence and increased with age. The attractancy peaked at 28 days after emergence and above. The males were also found to require a higher dosage of methyl eugenol (1 mg) for optimal response. These results are in contrast with those of B. papayae reported previously. The response to methyl eugenol was also observed to correspond with the age when first mating was performed.

After eclosion, both sexes of B. carambolae mated approximately 2 weeks later and showed significantly lower matings/individual when compared with B. papayae in a 60-day observation period. Both sexes of B. papayae and males of B. carambolae were able to remate on the next day. However, B. carambolae females required a minimum refractory period of 8 days in order to be sexually receptive again.

During the 60-day period, the mating propensity in B. papayae (100% success) was higher than B. carambolae (71–87% success) (P < 0.05). This observation was substantiated by a higher intraspecific mating success of B. papayae as compared to B. carambolae in a field cage (P < 0.001).