The annual migration of Christmas Island’s red crabs – where millions of creatures cover its beaches as they make their way from land to sea – is a true natural spectacle.
However, little is known about whether and how the species might be impacted under the future environmental conditions created by the changing global climate.
A new study by scientists and graduates at the University of Plymouth has investigated one aspect of how such shifts might affect its earliest development.
Specifically, the research focused on whether lower salinity – caused by future increased rainfall during the tropics’ monsoon season, which would in turn dilute coastal waters – might delay the development of crab embryos.
To understand that, the researchers exposed fertilised late-stage embryos of the crab (Gecarcoidea natalis) to four different levels of sea water salinity.
Over the space of 24 hours, they then used a specially-developed and autonomous analysis technology – the
LabEmbryoCam
– to measure a number of the embryos’ key developmental and physiological traits.
Previous research had shown that environmental drivers such as salinity can impact the timing and duration of developmental events in aquatic early life stages of crustaceans.
However, the results of this new study found that changes in salinity had no impact on the time of first heartbeat, time of hatching, first in-egg embryonic and post-hatch heart rate, or post-hatch movement.
Writing in the study, published in the Journal of Experimental Biology, the researchers say the findings may – on the face of it – appear positive for the red crabs’ future survival.
However, with the study focused on just one environmental stressor – and one period of embryo development – they also highlighted the importance of considering all early life stages when fully characterising the effects of environmental drivers on crustacean development.
Dr Lucy Turner
