Silent means Deadly, Caterpillars Walk the Talk, Mysterious Eclipse, Devon Ice Cap Loses its Cool, The Anthropocene - the Epoch of Humans, Science Fact or Fiction: Grey Hair

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Silent means Deadly

Cricket getting silencing surgery, courtesy D. Logue

When crickets fight, there's a lot of noise. Not just the clashing of mandibles and the clicking of legs, but the cricket equivalent of "trash talking" as well. Dr. David Logue, a biologist at the University of Puerto Rico and his colleagues from the University of Lethbridge in Alberta, were interested in what would happen when the crickets couldn't make the sounds associated with their fights. What they saw was mayhem. Crickets, who were either naturally silent or had their noisemakers removed, fought viciously, longer, and more violently than those full of sound and fury. Apparently, these insects use bluster not to provoke, but to avoid violence.

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Related Links

Paper in Proceedings of the Royal Society:B
Dr. Logue's web page
Ealier paper on silent crickets in Biology Letters
Earlier Quirks story on silent crickets

Caterpillars Walk the Talk

Masked birch caterpillar (Drepana arcuata) courtesy J. Yack

The masked birch caterpillar wards off its rivals in a couple of different ways; it drums its jaw against the leaf on which it lives, and it drags its anus to make a scraping noise. Dr. Jayne Yack, a neuroethologist in the Department of Biology at Carleton University in Ottawa. believes that jaw drumming evolved from the more primitive territorial rituals of biting, butting and hitting. Anal scraping evolved from walking, as in crawling in the direction of intruders to attack them. Aggressive movements toward rivals have become ritualized into signals that have evolved to avoid physical confrontation and injury.

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Related Links

Paper in Nature Communications
News release from Carleton University
Dr Yack's lab
Not Exactly Rocket Science blog (with video)

Mysterious Eclipse

Photograph courtesy John D. Monnier, U of Michigan

For the first time, astronomers have observed the mysterious dark companion in a binary star system that has been a puzzle for more than 175 years. In 1821, the star Epsilon Aurigae was discovered to be an eclipsing double star system; its eclipse happens every 27 years and lasts nearly two years. Astronomers theorized that the second object was a star so dim that its own light wasn't visible from earth. In turn, they believed it was being orbited edge-on by a thick disc of dust. Using new technology developed at the University of Michigan, astronomer Dr. John Monnier has new images that show this is exactly the case. A dark, dense, but partially translucent cloud can be seen passing in front of Epsilon Aurigae.

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Related Links

Paper in Nature
News from the University of Michigan (with video)
Dr. Monnier's web page
CBC News story

Devon Ice Cap Loses its Cool

Ice and rock dominate the landscape on the Devon Island ice cap, photo by Brad Danielson

The Devon Ice Cap is about 14,000 square kilometers in area, as much as 880 meters thick - the second largest ice mass in the Arctic, after the Greenland Ice Cap - and apparently shrinking by the minute. Dr. Sarah Boon, a geographer from the University of Lethbridge, led a group that's been studying this huge mass of ice on Devon Island, and their latest work indicates that the ice cap has been losing mass since 1985. This is worrying, but they hope understanding the ice of Devon Island better might provide insights into the more important dynamics of the much bigger Greenland Ice Cap.

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Related Links

Paper in Arctic (direct pdf link)
News release from Arctic Institute of North America
Devon Ice Cap study project
Dr. Boon's web site

The Anthropocene - the Epoch of Humans

Many geologists think that we have now entered a new geological interval of time. Humans have had such a tremendous impact on the Earth, that we've made ourselves geologically distinct. Physically, with our digging, building, and damming; biologically, with the way we've changed the very species that live on the planet; and chemically, with the traces we'll leave in the rocks formed from the sediments we deposit today, we're creating our own layer in the geological history of the planet. A new name has been proposed for this new geological epoch - the Anthropocene. Dr. Jan Zalasiewicz of the Department of Geology, University of Leicester, has been part of a committee of geologists who are proposing the idea of our time as part of the official geological time line. He thinks it's clearly scientifically based, but that it also confirms the scale of impact that we humans have had on our planet.

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Related Links

Paper in Envrionmental Science and Technology
News release from the University of Leicester
Dr. Zalasiewicz's web site
Earlier paper by Dr. Zalasiewicz in GSA Today (direct pdf link)

Science Fact or Fiction - Grey Hair

From time to time, we'll present a commonly held idea or popular saying - and ask a Canadian scientist to set us straight on whether we should believe it or not. Today's popular belief was submitted to us by Ellen Wardell of Saskatoon: "Stress causes your hair to turn grey." To get to the roots of this issue we've contacted Dr. Jason Rivers, a clinical professor of dermatology at the University of British Columbia.

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Theme music bed copyright Raphaël Gluckstein.
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