Use of time-lapse cameras to monitor beetle activity on fruiting bodies of Fomitopsis pinicola

Abstract

Insects and fungi are the major contributors to forest biodiversity. It is apparent that insects have an ecologically important effect on fungal communities in dead wood systems. Beetles frequently visit the fruiting bodies of polypore wood-decay fungi to feed on spores and have the potential to act as targeted dispersal vectors by carrying and disseminating fungal propagules. However, and despite the hypothesised importance of this interaction, we know little of who these beetle visitors are, when and how often they visit, or how long a typical visit lasts. In this study, beetle activity on fruiting bodies of Fomitopsis pinicola (Sw.) P.Karst. was monitored by using commercial time-lapse cameras at 11 different sites in Østmarka in Southern Norway. Insect visitation studies have traditionally relied on strenuous manual observations. The goal of this study was to evaluate the use of time-lapse cameras as an alternative to manual observations of beetle activity on polypores, something which has not previously been attempted. Despite various technical difficulties and a high proportion of images being of poor quality (> 60%), the time-lapse cameras were able to generate a large amount of high-quality image data, from which the activity of three beetle species could be estimated. The image quality did not allow for detailed taxonomical identification of small beetle species (> 5 mm), so time-lapse cameras should be seen as a supplement to traditional methods as opposed to a complete replacement. The method can without doubt be improved and developed further. Time-lapse cameras thus have great potential for use in entomological research focusing on fungus-insect interactions.