Reproductive interference in insects

1. Reproductive interference occurs when members of different species engage in reproductive interactions, leading to a fitness cost to one or both actors. 2. These interactions can arise through signal interference (‘signal‐jamming’), disrupted mate searching, heterospecific rivalry, mate choice errors, or misplaced courtship, mating attempts or copulation. 3. We present a definition of reproductive interference (RI) and discuss the extent to which a failure of species discrimination is central to a definition of RI. 4. The possible mechanisms of RI are reviewed, using a range of insect examples. 5. Some of the causes and consequences of RI are discussed, focusing in particular on mating systems and mating system evolution. 6. We conclude by considering future ways forward, highlighting the opportunities for new theory and tests of the old theory presented by reproductive interference. Reproductive interference (RI) can arise through processes such as: signal jamming; mis‐directed courtship or copulation; mis‐directed intrasexualrivalry. We focus on RI and mating system evolution. We stress that RI may often involves a failure of species discrimination, but this need not always be the case.