Summary: A new study by the University of Plymouth shows that sandhoppers (Talitrus saltator) use magnesium ions to enter a torpid state during winter, effectively acting as a natural “sleeping pill.” This adaptation allows them to survive harsh conditions by staying inactive in burrows. The research highlights how sandhoppers increase their magnesium levels to slow down in cold temperatures and further increase it for deep sleep, ensuring their survival without needing food or water.
Key Takeaways:
- Findings indicate that sandhoppers increase magnesium ions in their bodies to enter a torpid state during winter, acting as a natural sleeping pill.
- This magnesium-induced torpidity allows sandhoppers to stay inactive in burrows, avoiding harsh winter conditions without needing food or water.
- The study raises questions about how rising global temperatures might affect sandhoppers’ sleep and survival mechanisms.
Magnesium compounds are a common ingredient of many remedies designed to help people wind down, sleep, and escape the stresses of modern life.
However, a new study has shown that humans are not the only ones using forms of the chemical to help them survive challenging conditions.
In tests conducted on beaches in Cornwall, and in the laboratory at the University of Plymouth, scientists confirmed the findings of previous studies which showed large sandhoppers (Talitrus saltator) increase the levels of magnesium ions in their bodies as temperatures fall. This slows them down so they are less active than they would be during the warmer months.
Magnesium-Induced Torpidity
However, the new study has shown that when they want to enter a period of deep sleep the creatures have the means through which to increase their magnesium levels even further—in some instances more than doubling them.
Essentially acting as a natural narcotic, the magnesium puts the sandhopper into a torpid state. This enforced rest means that the creatures stay hidden in burrows up to 30 centimeters beneath the beach surface, without the need to come up for food or water, and to some extent buffered from the wintery conditions at the surface of the sand.
The study, published in the Journal of Experimental Marine Biology and Ecology, which focused on the sandhopper population at Portwrinkle, in South East Cornwall, was carried out by professor of marine zoology John Spicer, PhD, and BSc (Hons) Marine Biology graduate Jack Bush.
Insights into Sandhopper Behavior
They say it sheds further light on why large sandhoppers seem to disappear from sandy beaches during cold winter weather. Spicer has spent decades studying the impact of temperature on marine and coastal species, including a number of studies on sandhoppers in Scotland.
“It has been known for over a century that large sandhoppers, relatives of shrimp and crabs, can overwinter buried deep in the sand at the top of beaches away from the reach of the tide. What our study shows is that they may help themselves ‘go to sleep’ by allowing a natural narcotizing agent, magnesium ions, to build up in their body fluids,” Spicer says in a release. “Fluids containing magnesium, like Epsom salts, are routinely used by humans to relax but also when aquatic animals are being examined as part of scientific investigations. Our study shows nature has also found a way to do that without outside involvement.
“That said, as it’s a temperature-dependent process, it does raise questions over what will happen as our world warms. Will sandhoppers no longer sleep and just eat decomposing wrack all day long? Or will they change their sleeping habits by adapting the way they manage the magnesium in their body fluids?”
Photo caption: A sandhopper found around 30 centimeters beneath the beach surface at Portwrinkle, Cornwall (UK). The creature had elevated its magnesium levels to enter a torpid state meaning it could survive the cold winter months
Photo credit: University of Plymouth
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