Dynamic $β$-VAEs for quantifying biodiversity by clustering optically recorded insect signals

While insects are the largest and most diverse group of terrestrial animals, constituting ca. 80% of all known species, they are difficult to study due to their small size and similarity between species. Conventional monitoring techniques depend on time consuming trapping methods and tedious microscope-based work by skilled experts in order to identify the caught insect specimen at species, or even family level. Researchers and policy makers are in urgent need of a scalable monitoring tool in order to conserve biodiversity and secure human food production due to the rapid decline in insect numbers. In order to improve upon existing insect clustering methods, we propose an adaptive variant of the variational autoencoder (VAE) which is capable of clustering data by phylogenetic groups. The proposed dynamic beta-VAE dynamically adapts the scaling of the reconstruction and regularization loss terms (beta value) yielding useful latent representations of the input data. We demonstrate the usefulness of the dynamic beta-VAE on optically recorded insect signals from regions of southern Scandinavia to cluster unlabelled targets into possible species. We also demonstrate improved clustering performance in a semi-supervised setting using a small subset of labelled data. These experimental results, in both unsupervised- and semi-supervised settings, with the dynamic beta-VAE are promising and, in the near future, can be deployed to monitor insects and conserve the rapidly declining insect biodiversity.