Invertebrates on fungal fruit bodies

Fungi and invertebrates comprise a major part of biodiversity in dead wood ecosystems and invertebrates depend on fungi to utilise the dead wood resource. Many invertebrates also visit the long‐lived fruit bodies of wood‐decay fungi to feed on spores, the hymenium or other invertebrates. However, as traditional sampling methods are labour‐intensive, we know little of these interactions.

In this study, we use time‐lapse cameras to monitor invertebrates visiting the hymenium of a common wood‐decay fungus, Fomitopsis pinicola, and explain their activity in terms of temporal variation, temperature and presence of Gyrophaena boleti, a highly abundant fungivorous beetle living primarily in fruit bodies of F. pinicola.

The most common invertebrates on F. pinicola fruit bodies were Coleoptera, Araneae, Diptera, Gastropoda and Chilopoda. The invertebrate activity exhibited strong temporal variation with higher abundance during night and, for Coleoptera, earlier in the season. We discuss how this might correlate with the sporulation period of F. pinicola. The presence of G. boleti had a positive impact on the predatory Lordithon lunulatus and Ipidia binotata, and a negative impact on the fungivorous Thymalus limbatus and Peltis ferruginea. Chilopoda and L. lunulatus were ephemeral visitors, while the fungivorous Coleoptera and Araneae stayed the longest.

We estimated the invertebrates' visitation frequency and duration, which would be time‐consuming to obtain with traditional methods. We offer improvements to our method and urge future research on invertebrate–fungus interactions to quantify invertebrate visits to fungal fruit bodies.

Methods
Monitoring of 19 Fomitopsis pinicola fruit body hymenia with time-lapse cameras taking pictures every ten minutes throughout the day from April-September in 2019 and 2020. The cameras have in-built flash and thermometers. Images were manually annotated to the lowest possible invertebrate taxonomic rank.