Predation risk of caterpillar prey is shaped by arthropods and urbanisation in an urban-agricultural landscape: a common garden experiment

Abstract

Prey-predator interactions are fundamental to ecosystem balance, with predators regulating prey populations. Yet, the degree of this interaction varies, depending on the conditions and structure of the ecosystem. We investigated the influence of leaf herbivory, predator types, and levels of urbanisation on the predation risk of artificial caterpillar prey within an urban-agricultural landscape in southcentral Mindanao, Philippines. Four hundred and seventy-three (31.53%) of the 1500 artificial caterpillars exposed in the field were predated. While there was a significant difference in the predation frequency of caterpillar prey between herbivory treatments, our generalised linear mixed model showed a marginal influence on predation risk, but predator type and local landscape showed significant and relatively higher effects. Arthropods were the most significant predators followed by mammals, birds, and reptiles. Furthermore, an increasing proportion of urban developed areas was associated with a decreased risk of predation in artificial caterpillar models. This study implies that regardless of the specific foraging locations chosen by the arthropod prey, predators are likely to prey on available prey in urban and agricultural landscape environments. Our study provides additional evidence that urbanisation can reduce prey-predator interactions. Considering our findings, we suggest that increasing tree cover and green spaces may effectively improve prey-predator interactions in urbanised areas.