An investigation of the direct and trans-generational costs of ejaculate depletion in Telostylinus angusticollis (#203)
Males can be limited by the number of ejaculates that can be produced, as well as the quality of ejaculate transferred. This may be costly not only due to the possibility of decreased fertilisation potential, but due to the decrease of components found in the semen such as seminal fluid protiens (SFPs) that can stimulate oviposition and influence paternal effects. It is known that frequent mating can reduce the number of progeny sired by the male, however it is not known if frequent mating can also decrease paternal effects. In this study, we investigate the consequences of ejaculate depletion in the Australian neriid fly, Telostylinus angusticollis. Males were either allowed to mate frequently over 6 hours (mated treatment) or exposed to females but prevented from mating (non-mated treatment), and then paired with a standard virgin female to quantify male mating rate, reproductive output and paternal effects on offspring viability and condition. Although males from the mated treatment exhibited reduced mating rate following the treatment period, there was little evidence of a cost of previous mating in terms of reproductive output or paternal effects. However, mating treatment affected the rate of reduction in male accessory gland size with each subsequent mating, and accessory gland size affected larval viabilty. These results indicate that males of T. angusticollis do not suffer an obvious cost to frequent mating on reproductive performance. However, these results suggest that frequent mating depletes the accessory glands, with potential consequences for offspring viability.