Mate sampling strategy in a field cricket: evidence for a fixed threshold strategy with last chance option

The strategy females use to sample potential mates can influence mate choice and thus sexual selection. We examined the mate sampling strategy of the cricket Gryllus lineaticeps. In our first set of experiments, we simultaneously presented three different chirp rates to females. The set consisted of three trials, each covering a different range of chirp rates. Independent of chirp rate range, female G. lineaticeps preferred rates that were above 3.0 chirps/s to rates that were below 3.0 chirps/s. Females did not discriminate among chirp rates that were below this threshold and did not discriminate among chirp rates that were above this threshold, suggesting that they express a fixed threshold sampling strategy. In our second experiment, females were presented sequentially with a fast chirp rate and then a slow chirp rate. When the interval between presentations was 20 min, females showed significantly weaker responses to the slow rate than to the fast rate. However, when the interval between presentations was 24 h, female responses to the slow and fast rate did not significantly differ. The latter result suggests that females lower their threshold of acceptance when they have not recently experienced highly attractive song types. This lower acceptance threshold is probably adaptive, as it would allow females to avoid paying high search costs, and to reproduce, only when low-quality males are available. Our results are consistent with a rarely considered sampling strategy (fixed threshold with last chance option strategy) and highlights the importance of the timing of social experience for mate sampling.