Activity and burrowing behaviour of wireworms (Agriotes spp.) in the presence or absence of roots

Abstract

Click beetle larvae (Elateridae), commonly known as wireworms are burrowing insects found commonly in many habitats. Some species can be a significant agricultural pest, reducing crop yields and quality of harvestable parts such as Agriotes spp. which are common in Europe and parts of North America. X-ray Computed Tomography (CT) has previously been demonstrated as a viable method for investigating wireworm interaction in soils with living plants. In this study, we used X-ray CT to visualise and quantify wireworms, their burrow networks and the root architecture of maize, barley and bare soil over a 96-hour time period order to monitor the typically cryptic behaviour of these organisms. Components within these CT scans were subsequently segmented and volume, size and complexity data collected. Wireworm burrow volume was significantly greater in bare soil compared to maize and barley planted columns, suggesting a behavioural difference in the wireworms elicited by the presence of root structures. Burrow volume was significantly greater at 96 h compared to 24 h. Burrow networks with maize were significantly shallower and less complex in structure compared to their barley and bare soil counterparts. Burrow network depth did not vary significantly over time. The presence and species of crop roots caused differences in wireworm behaviour, leading to variation in both the volume and structure of the burrow networks. Further work is needed to determine the specific type of behaviour of wireworms (e.g. random searching behaviour) and the mechanisms that influence it (e.g. CO2 and Volatile organic compound gradients).