How much should we care about insect–plastic interactions?

The world relies heavily on plastic use in daily life, leading to increased global concern over mismanagement of plastic waste, its entry into natural environments, and impacts on living organisms. Over time, plastic in the environment will break down into microplastics (5 mm-1 µm) and eventually into nanoplastics (<1 µm), which are found in many living organisms, including insects. Insects are also of particular interest in plastic waste management because of their potential role in degrading plastic waste. However, these applications have not yet been scalable, and the ubiquity and consequences of plastic ingestion are unclear. Further, insect-plastic interactions are complicated by the seemingly endless combinations of shapes, types, sizes, and concentrations of plastics. As a result, we have a fragmented body of literature and unclear patterns that raise questions about whether resources put toward studying insect-plastic interactions should be placed elsewhere and why, or how much, we should care. Nevertheless, insects are vital members of almost all ecosystems, and their populations are already threatened by numerous stressors; thus, ignoring another potential threat would be unwise. To reveal clear patterns that can shape how we invest in mitigating and harnessing insect-plastic interactions, we pose six major questions. We also present a matrix of 'care' that combines the likelihood of exposure with the strength of the outcome of the interaction. We aim for these questions and matrix to serve as tools to guide broader participation, research priorities, and allocation of resources, to tackle what is currently a prodigious, but worthy, pursuit.