Can a nest associate fish use an introduced host?—Brood parasitism by Pungtungia herzi toward introduced Coreoperca kawamebari

The minnow Pungtungia herzi is a nest associate spawner that utilizes the spawning nests of other species, including freshwater perch, goby, and catfish. We investigated whether the minnow can utilize a nonindigenous host that has been recently introduced by human activity. In the Makuni River, Kii Peninsula, central Japan, the minnow has originally used the nests of the catfish Pseudobagrus nudiceps, which are located beneath rocks. Our field observations revealed that the minnow also uses the nests of the recently (~5 years ago) introduced perch, Coreoperca kawamebari, which are located at the stems of submerged plants. However, the frequency of utilization was lower than that in the native range of C. kawamebari, suggesting that the minnow has not yet fully used the new host. The new host may positively affect the population size of this brood parasite through the extension of the successful reproductive season of the minnow.