Flight behaviour attenuates the trade-off between flight capability and reproduction in a wing polymorphic cricket

Flight-dimorphic insects have been used extensively to study trade-offs between energetically costly traits. Individuals may develop and maintain structures required for flight, or alternatively they may invest in reproduction. Previous experiments have not examined whether flight itself might affect investment into reproduction. As in other Gryllus species, flight-capable individuals of the wing polymorphic cricket, Gryllus texensis, incur an apparent reproductive penalty for being able to fly, expressed as smaller ovaries in females and lower courtship propensity in males, than their flight-incapable counterparts. We find that a short bout of flight eliminates the trade-off. Two days after the flight, the ovaries of flight-capable females were comparable with those of short-winged females. Similarly, flight markedly increased the probability of courtship behaviour. Our results suggest that the impact of the flight–reproduction trade-off described in earlier studies may have been overestimated.