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Most people don't want to think about cockroaches the size of a small mouse, let alone amorous ones. But University of Lethbridge biologist David Logue has spent hours studying the sexual habits of male Madagascar hissing cockroaches, a large and vocal species endemic to the island off the southeastern coast of Africa.
Dr. Logue, who breeds the roaches in his laboratory, has found that they fall into two distinct groups when it comes to sexual behaviour. They are either horny or have a low libido. Horny males are more aggressive and put more effort into the two basic moves involved in roach courtship: hissing and genital thrusting. In fact, horny roaches love sex so much that they will hiss and thrust at pretty much any other roach that moves, male or female.
While it is a waste of time and energy courting males, Dr. Logue has discovered that female cockroaches like the high-energy approach of the libidinous males. “They had the most kids,” he says.
Low-libido roaches are pickier; they don't waste time approaching other guys. But the ladies don't find their laid-back approach as sexy, so they don't sire as many offspring.
Madagascar Hissing Cockroaches are on sale in a Bangkok's market Tuesday, Aug. 20, 2002. The Thai government is cautioning people against a new fad sweeping Bangkok - raising giant African cockroaches as pets - saying the bugs could become a health risk and public nuisance if let loose. (AP)
Videos
Footage of the sexual habits of male Madagascar hissing cockroaches
Dr. Logue will present the findings of his study Aug. 16 at the annual meeting of Animal Behaviour Society in Snowbird, Utah.
SCUBA FOR INSECTS
Hundreds of species of insects, such as backswimmers, water boatmen and Fisher spiders, spend extended periods of time underwater, breathing air from a bubble attached to their bodies. Now, a team of researchers, including the University of Alberta's Morris Flynn, have found why some of these bugs can dive down 30 metres, while others can only dip a few centimetres below the surface.
The key, Dr. Morris and his colleagues discovered, is how much bristly hair the insects have. The bristles are what keep the air bubble in place and stop it from popping as the animals go under. Insects with plenty of hair can dive much deeper than those with sparser hair.
Insects take in oxygen and excrete carbon dioxide through tiny holes in their sides called spiracles, Dr. Morris says. The process seems to work as well in an air bubble as above the water.
Dr. Morris, who moved this summer to the University of Alberta in Edmonton from the Massachusetts Institute of Technology, says it is unlikely that humans will ever be able to dive using an air bubble as an external lung, but it might be possible to design one that a robot could use to draw oxygen to power a fuel cell.
Dr. Morris and his colleagues have published their findings in the Journal of Fluid Mechanics.
REAL NATURE NEEDED
Nature has the power to soothe. But what about nature scenes on television?
In an initial experiment in 2004, three researchers at the University of Washington in Seattle gave seven faculty members and staff with windowless offices a 50-inch plasma screen that displayed a real-time image of the outside world as seen from a camera on top of their building. The participants reported feeling smarter and more connected to nature.
But then the researchers conducted a second experiment involving 90 undergraduate students who were asked to perform a complicated task. This was mildly stressful and caused the students' hearts to start beating more rapidly. The heart rates of students who could look out a window during the experiment returned to normal much faster, while the same scene on a plasma screen proved no more restorative than looking at a blank wall.
“As a species, we need interaction with nature for our physical and psychological well-being,” says Peter Kahn, a professor of psychology and lead author of a paper published recently in the Journal of Environmental Psychology.
ARCTIC HEAT
An international team of marine scientists has discovered hydrothermal vents in the Arctic Ocean spewing water that is almost 300 degrees Celsius. The five hot-water vents, on the Mid-Atlantic Ridge between Greenland and Norway, are the most northern ever discovered.
Hydrothermal vents are among the most extreme environments on Earth: The hottest water in the world bubbles up from cracks in the sea floor, along with minerals, metals and poisonous gases, a seemingly toxic brew that nourishes bizarre sea creatures and microbes.
The latest discovery was made on an expedition led by Rolf Pedersen, a geologist with the University of Bergen in Norway. Five years ago, he and his colleagues found the first Arctic vents 190 kilometres to the south. They say the ecosystems around these northern vents appear to be different from vent communities found in other parts of the world.
Anne McIlroy is The Globe and Mail's science reporter.
