Using temporary emigration to inform movement behaviour of cave‐dwelling invertebrates: a case study of a cave harvestman species

1. Understanding of animal movement behaviour is critical for developing appropriate conservation strategies because of its profound implications for predicting species' responses to perturbations. To date there is a substantial knowledge gap of the movement behaviour of subterranean invertebrates. 2. In this study temporary emigration (TE), the probability that an individual is absent from the cave on a given sampling occasion, was used as a method to inform on the movement and behaviour of cave‐dwelling invertebrates. Because these animals are difficult to study with traditional tracking techniques, the capture–recapture (CR) modelling framework was used to assess TE and to account for imperfect detectability and unobservable states. 3. Specifically, the influence of season, sex, and surface weather variables on the TE of the facultative cave‐dwelling harvestman species, Paranemastoma sillii sillii (Herman, 1871), was investigated. Multistate CR models were used while accounting for individual heterogeneity on 999 individually marked adults of two populations inhabiting two caves, located in southwestern Romania. 4. Harvestmen demonstrated clear heterogeneity and seasonality in TE. Findings showed that the TE of harvestmen exhibited variation between caves and there was little support for surface weather variables influencing TE and for sex‐specific TE patterns. 5. These results show that the study of TE patterns is useful to gain valuable insights into movement and intrinsic behavioural processes of cave‐dwelling harvestmen. The method could potentially be used for other invertebrate groups with similar movement characteristics and when traditional tracking techniques are difficult.