Copulation of the Japanese potamid crab <i>Geothelphusa dehaani</i> in their natural habitat

Abstract

Mating pairs of the potamid crab Geothelphusa dehaani were observed in a mountain stream of Fukuoka Prefecture, Japan, during the survey of over ca. 3-year period. Five mating pairs in copulatory posture were found in the afternoon in October and November. Mating pairs remained immobile for at least several minutes. No guarding behavior was observed after the release of copulation. They were all found on the bottom substrate under the water in pools. Females were either in the soft-shell or hard-shell condition, and even included one juvenile among the adults.

Effect of local‐ and landscape‐scale factors on the distribution of the spring‐dependent species Geothelphusa dehaani and larval Anotogaster sieboldii

“…Although G. dehaani can inhabit both aquatic and terrestrial habitats (Okano et al, 2003), juveniles prefer aquatic habitat (Wada, 2017). The copulation behavior of G. dehaani is rarely reported, but a recent study reported that mating occurs in water and lasts for several minutes (Kobayashi & Archdale, 2020). These observations indicate that the species likely has a high dependence on spring water, at least during its early life stages.…”