Speaker
Description
New selection pressures can cause rapid evolutionary change. This has, for example, been observed in the Pacific field cricket Teleogryllus oceanicus on Hawai’i, which is under harsh predation pressure from the parasitoid fly Ormia ochracea. The fly locates the male crickets by their mating calls and deposits its larvae on the cricket which gets eventually killed. Within less than 20 generations, a sex-linked mutation causing an alteration to the wing structure became dominant on most islands. Males with this mutation are mute and thus safe from the fly. Yet, mute males cannot attract females from afar. They therefore keep close to the remaining calling males. This mutation creates a trade-off between sexual selection and parasite protection. We use mathematical models to answer under what scenario in this system evolutionary rescue would be possible and how a trade-off causing mutation shapes the dynamics and probability of rescue.