Weed biocontrol by carabids – Lessons from two decades of research

Seed disperal is a critical process in the demogrpahy of annual weeds. Once dispersed, seed predators including carabid (Carabidae) beetles, consume many weed seeds on the soil surface. Yet the importance of carabids, and insects more generally, to weed biocontrol had been seldom studied until the early 2000’s. Substantial research effort, particularly in Europe and the US, has since been directed toward understanding carabids and their connection to weed biocontrol. What has emerged is a greater appreciation of the role carabids play in weed seed predation, with studies documenting regulation of the weed seedbank by carabids, under certain conditions. Multidisciplinary teams have identified seed traits associated with predation by carabids, the foraging behavior of carabids toward weed seeds, and even the cues guiding these ground dwelling arthropods to select seeds of specific weed species over others. Further work has improved the understanding of the connection between weed seeds and carabid food webs, and the importance of this interaction as a key agroecosystem service. Despite substantial progress in developing a more holistic understanding of weed biocontrol by carabids, much remains to be studied. This presentation will review the progress made in advancing our understanding of biocontrol by carabids, the state of current knowledge, and research gaps that need to be addressed by future studies.