Female remating inhibition and fitness of Bactrocera dorsalis (Diptera: Tephritidae) associated with male accessory glands

Polyandry is widespread among insects but male accessory gland products can influence the propensity of former mates to copulate later with other males. In addition, females may receive nutritional supplements in accessory gland fluids that substantially increase fitness regardless of whether remating has been inhibited. In this study, we investigated polyandry in female Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) and the relationship between remating and male accessory gland contents. Similar to other fruit flies, 2 kinds of accessory glands were observed in male B. dorsalis. Male mesodermal accessory glands expanded significantly in length and area when copulation finished. A remating refractory period occurred in B. dorsalis females, but it did not differ in duration following copulations with either virgin or non-virgin males. Besides, we found that virgin females lived longer, but produced much fewer eggs than mated females. Remating with a refractory period resulted in more eggs being laid and offspring produced than continuous exposure to 2 mates. In addition, females in the continuous presence of 2 males produced significantly more offspring than females with only 1 male present. We also observed that increases in male and female age reduced the rate of fertilization. These results indicated that multiple matings increased the fitness of B. dorsalis females, although remating inhibition existed in B. dorsalis fruit flies. It is the great reproductive ability of B. dorsalis that enable flourishing populations to occur in wild.