The impact of invasive alien vertebrates on native insects

Thousands of vertebrate species have been intentionally and unintentionally introduced to new locations beyond their native range. Many of these species have established alien populations, and some have become invasive and caused adverse impacts on native biodiversity. Research has improved our understanding of how these impacts affect native vertebrates, but comparatively little is known about how they affect native invertebrates, including insects. Yet, alien vertebrates may directly or indirectly interact with native insects wherever they are introduced (e.g., directly, by feeding on insects, and indirectly, by profoundly altering ecosystems). In this chapter, through a literature review, we identify direct and indirect impacts caused by a range of alien vertebrate species, and from many regions worldwide. We find that most research has focused on impacts affecting individuals of a native insect species, often by analyzing the stomach or fecal contents of an alien vertebrate species, and that reports of positive impacts are scarce and often inferred rather than measured. We conclude that the impacts of alien vertebrate species on insects remain largely unexplored. Future studies should aim to identify and quantify population-level impacts. Their robustness may be improved by adopting exclusion and before/after experiments, and collaborating with entomologists and insect ecologists.