Invasive Crabs
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Behavioural innovation is thought to play an important role in enabling animals to cope with environmental change. Research on animal innovation has focused on terrestrial and freshwater vertebrates, but few animals face environmental variation as extreme as those living in littoral zones, where physical and social conditions change dramatically from moment to moment.
The aim of this thesis was to study the chemical communication involved in aggressive and reproductive behaviours in the European lobster (Homarus gammarus). Both male and female H. gammarus established and maintained dominance, but the sexes used different strategies for dominance maintenance.
In ancient China crabs were smashed open and thrust into wounds in battles because chitosan is antimicrobial, meaning it heals and kills bacteria.
Chitosan's properties allow it to rapidly clot blood and promote hemostasis (stops bleeding). Chitosan bonds with platelets and red blood cells to form a gel-like clot which seals a bleeding vessel.
Last September, ecologist David Johnson and his colleagues were at a Virginia salt marsh at low tide. There, they observed some unexpected behaviour by an aquatic predator.
They witnessed blue crabs waiting in shallow, water-filled pits, stalking and ambushing fiddler crabs above land, at low tide.
After capturing their prey, they would carry it back to the pit to consume it, then discard the large claws of the fiddler crab at the edge of the pit.
While it’s a fun, challenging and tasty experience for most, more than 20 divers have lost their lives during mini season in the last decade.
Through analysis of these tragic deaths, researchers at Divers Alert Network (DAN) have identified the most relevant contributing factors and most important safety practices for divers participating in the annual event.
These tips probably won’t surprise you, but sometimes the most basic precautions are the most likely to save a life.
Researchers from the University of Bayreuth, Germany discovered how two hermit crab species co-exist on the same beach without fighting over limited resources like food or shelter.
Scientists at the University of Exeter studying rockpool prawns (Palaemon elegant) have discovered that they exhibit different personalities, and those that are "shy" tend to fare better when competing for food.
The findings of their study was published in Volume 140 of the journal Animal Behaviour.
In the study, the prawns, all taken from the Gyllyngvase beach in Falmouth, were tagged and tested on their level of boldness by placing them in an unfamiliar tank and observing how much they explored and ventured to the centre.
Investigating deep waters off Bahamas, US-based researchers recorded the glow of tiny bioluminescent species using a submersible vehicle.
Descending to sites between 600 and 1000m down, the scientists observed flashes of bioluminescence where plankton collided with boulders and corals.
The team also studied how crustaceans react to this light, and found previously unknown sensitivities to blue and ultra violet wavelengths.
King crabs invade Norwegian waters.
The Cold War has been over for more than two decades, but a relentless red army of monster crabs are still pouring over the border of Russia into Norway. The crabs are feared by environmentalists, but not by scuba divers.