Komine, H., Fukasawa, K., Akasaka, M., Watari, Y., Iwai, N. and Kaji, K. (2020), Rapid behavioural responses of native frogs caused by past predation pressure from invasive mongooses. Journal of Zoology, vol. 310, pp. 126-134. https://doi.org/10.1111/jzo.12734
It is well known that strong predation pressure by invasive predators cause native prey populations to decline. However, few studies have reported invasive predators induce evolutionary changes in a native prey in a short time scale. This could be because strong predation pressure by invasive species often causes the extinction of native prey before an evolutionary effect can be detected.
Recently, eradication projects successfully removed invasive predators and resulted in the recovery of native prey. We predicted that rapid responses can be detected by evaluating the behavioural traits of native prey populations having different histories of predator invasion. We examined the behavioural responses of a native frog, the Amami tip-nosed frog (Odorrana amamiensis), to the invasive mongoose (Herpestes auropunctatus) on Amami Island, Japan.
The native frog population was reduced by the mongoose; however, the eradication project by Ministry of the Environment Japan led to the recovery of the native frog populations, thereby providing an opportunity to evaluate the evolutionary impact of the invasive species. We hypothesised that spatial differences in flight initiation distance (FID) between frog populations can be explained by the spatial patterns of past mongoose predation pressure. We measured FID in 278 frogs at sites with different history of mongoose invasion.
We found that the native frog became more sensitive to the approach of a potential predator as the historical impact of the mongoose increased. This result suggests that past strong predation pressure by the mongooses drove a rapid behavioural response in the native frog. Our study suggests that such rapid behavioural responses of other native species can be detected not only after successful eradication projects, but also on currently invaded sites with different invasion histories.