Rethinking same-sex sexual behaviour: male field crickets have broad mating filters.

Same-sex sexual behaviour (SSB) occurs in many animals and is often treated as an anomaly requiring special explanation. One common explanation for SSB is mistaken identity. However, animals make similar 'mistakes' in other contexts-such as attempting to mate with immature individuals or inanimate objects. Framing such behaviours as 'mistakes' risks misinterpreting how animals make flexible mating decisions. Here we make a case for an alternative approach to thinking about SSB by instead considering an individual's mating filter. A broad filter means directing courtship toward anything that resembles a potential mate, whilst a narrow filter means only courting with receptive targets. We illustrate this approach by examining the mating filters of male Pacific field crickets ( Teleogryllus oceanicus ). We find that males engage in SSB but also misdirect courtship toward juveniles (but not plastic crickets). This finding suggests that SSB is not an anomaly and is better considered alongside other misdirected behaviours. We argue that by viewing misdirected behaviours through the lens of mating filters rather than as 'mistakes' we can build a more nuanced understanding of reproductive behaviour and begin to determine when having a broader mating filter can be advantageous.