Should I stay or should I go? Condition- and status-dependent courtship decisions in the scorpionfly Panorpa cognata

Abstract

The occurrence of prolonged courtship behaviour in many animal species is a well-known phenomenon. The duration of courtship may be influenced by both females and males, often with different interests. In the scorpionfly Panorpa cognata, males offer a salivary secretion as a nuptial gift before copulation. However, males do not immediately initiate copulation by the production of the salivary mass. Instead pairs usually engage in prolonged courtship interactions. Yet the duration of courtship is highly variable, ranging between a few minutes and several hours. Furthermore, courtship does not always result in copulation; instead females often terminate courtship and abandon the male. The duration and outcome of courtship are likely to be influenced by factors such as body condition and female mating history, because they might influence individual attractiveness and motivation to mate. I examined to what extent these factors influence both male and female courtship decisions. Mated females were less keen to remain in courtship for long and abandoned males sooner than virgin females. Yet, male mating behaviour was unaffected by female mating status. Counterintuitively, females in poor condition interrupted courtship sooner with increasing body weight of their male partner. In addition, heavier males initiated copulations sooner than males in poorer condition. However, this effect was evident only in interactions with females in poor condition. A possible interpretation of these results is that males attempt to prevent females in poor condition from leaving prior to copulation by initiating copulation faster.