Environmental drivers such as salinity can impact the timing and duration of developmental events in aquatic early life stages of crustaceans, including terrestrial crabs of the family Gecarcinidae. Low salinity delays larval development in land crabs, but nothing is known about its influence on the crucial late-stage encapsulated embryonic or immediate post-hatch development. Therefore, we exposed fertilised late-stage embryos of the Christmas Island red crab (Gecarcoidea natalis) to differing salinities (100%, 75%, 50% or 25% sea water) for 24 h during their spawning period and measured some key developmental and physiological traits. We found no effect of salinity on time of first heartbeat, time of hatching, first in-egg embryonic and post-hatch heart rate, or post-hatch activity duration. These results highlight the importance of considering all early life stages when fully characterising the effects of environmental drivers on crustacean development, including under climate change.

Author contributions

Conceptualization: L.M.T., J.I.S.; Formal analysis: L.M.T., Z.I.; Investigation: L.M.T., K.A.C., L.W., C.H.W., J.I.S.; Methodology: L.M.T., Z.I., O.T., J.I.S.; Software: Z.I., O.T.; Validation: L.M.T., Z.I., O.T., J.I.S.; Visualization: L.M.T., Z.I.; Writing – original draft: L.M.T.; Writing – review & editing: L.M.T., K.A.C., L.W., C.H.W., Z.I., O.T., J.S.

Funding

This research was supported by School of Biological and Marine Sciences, University of Plymouth internal funding. L.M.T. was supported by a University of Plymouth Research Culture Support Fellowship. O.T. was supported by a UK Research and Innovation (UKRI) Future Leaders Fellowship (MR/T01962X/1). O.T. and J.I.S. were supported by a Biotechnology and Biological Sciences Research Council (BBSRC) Follow on Fund (grant BB/W017938/1).

Data availability

The data that support the findings of this study are available from Zenodo: doi:10.5281/zenodo.10727747

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