Science briefs: Crabs can hear hungry fish coming

June 22, 2014 

Fish are not silent creatures. There’s a veritable symphony of sound echoing under the sea. They use their watery voices to relay distress, find prey, defend their nests, and attract mates. All this noise got Northeast University marine biologist Randall Hughes and her colleagues thinking: If fish are vocal creatures, can their prey hear them? And if so, how do they react?

In a new paper in the journal Proceedings of the Royal Society B, Hughes and her team show that sound plays at least as much of a role in mud crabs’ reaction to fish behavior as other widely studied cues –and possibly more.

“We showed that these crabs change their behavior in response to acoustic signals,” she said.

The researchers put the crabs into environments designed to mimic the natural world and transmitted various types of sound recordings of oyster toadfish, hardhead catfish and black drum.

“We pretty quickly saw that the crabs weren’t feeding as much in response to the predator sounds,” Hughes said.

The catfish and black drum had the most pronounced effect on the crabs’ behavior. northeastern.edu

Some trap-jaw ants spreading in Southeast

Trap-jaw ant species are active hunters with venomous stings and jaws powerful enough to fling themselves through the air. According to new research published in the journal Zootaxa, they are also spreading into new territory in southeastern states.

“The fact that some of these species are spreading is interesting, in part, because these giant ants have managed to expand their territory without anyone noticing,” said Magdalena Sorger, a Ph.D. candidate at N.C. State and co-author of a paper describing the ant species. “We know very little about these ants, including how they interact with native ant species in the areas they’re invading.”

This also is the first scientific article establishing the presence of trap-jaw species Odontomachus haematodus in the United States. Native to South America, haematodus was first unofficially recorded in Alabama in 1956. But the researchers found that the species has now spread across the Gulf Coast, at least as far east as Pensacola, Fla.

“Haemotodus is particularly interesting because it is larger and more aggressive than other trap-jaw ants in the United States,” Sorger said. ncsu.edu

New dinosaur’s skull sported fancy ‘wings’

Scientists have named a new species of horned dinosaur based on fossils collected from Montana and Alberta, Canada. Mercuriceratops gemini was approximately 20 feet long, weighed more than 2 tons and lived about 77 million years ago. Research describing the new species was published in the journal Naturwissenschaften.

Mercuriceratops means “Mercury horned-face,” referring to the wing-like ornamentation on its head that resembles the wings on the helmet of the Roman god, Mercury. Mercuriceratops had a parrot-like beak and probably had two long brow horns above its eyes. It was a plant-eating dinosaur.

“Mercuriceratops took a unique evolutionary path that shaped the large, frill on the back of its skull into protruding wings like the decorative fins on classic 1950s cars. It definitively would have stood out from the herd during the Late Cretaceous,” said lead author Michael Ryan, curator of vertebrate paleontology at The Cleveland Museum of Natural History. cmnh.org

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