On the ambivalence of granivorous carabids: Weed seed bank regulators, potential crop pests or both?

Carabids have long been beloved by collectors and have recently gained much attention in research as beneficial natural enemies of pests and weeds. With agricultural transformation towards lower herbicide use, carabids are expected to help carry the burden of weed regulation. While there is good evidence to found these expectations on, relying on seed-consuming carabids for natural weed regulation also has clear limitations. One of these is the fact that many carabids can be crop pests themselves, often in addition to their beneficial roles as natural enemies of pests or weeds. In a qualitative review, we gathered the available evidence for 72 carabid species acting as crop pests in 27 crops by damaging crops or consuming their seeds. Based on selected examples from different crops, we portray the historical impact and current state of carabids as crop pests. Due to the scarcity of recent reports, we expect that most carabids acting as crop pests are not a currently relevant economic problem across regions and crops, with beneficial ecosystem services provided by carabids outweighing possible damages. Yet, given the abundance of historical evidence and the current trajectory of agriculture towards a more sustainable management that aims to decrease chemical crop protection and increase carabid populations, we see a need to consider that carabids can, under certain conditions, act as crop pests. In this context, it will be crucial to get a better understanding of potential carabid crop pests around the globe, to identify under which conditions carabids switch roles from ecosystem service provides to ecosystem disservice providers and to understand how this role switching will be affected by climate change and agricultural transformation.