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October 31, 2005

From Vampiric Spiders To Owl Engineering

In honor of my favorite holiday - Halloween - I thought I'd post about some spooky creature behaviors of interest.

Blood-Sucking Spiders

Jumping spiders are creepy enough, but how researchers have found that there is a spider in Eastern Africa that lives on human blood. However, kind of like the Vampire Lestat feeding on rats because it's safer than dealing with stake-in-the-heart humans, the blood-sucking spiders have found that snacking on mosquitoes is a safer way to get their fix than getting smacked-down by a human...

They say the spider, which hunts blood-sucking female mosquitoes, is the only animal known to select its prey based on what the prey has eaten.

...

Spiders don't have the skin-piercing mouth parts needed to feed directly on human blood, but the mosquito-munching jumping spider appears to have got around this. The strategy has other advantages as well, Nelson points out.

"Blood-feeding is a dangerous activity," she said. "Animals that are bitten have a swatting response, and often the insect is killed."

By eating mosquitoes, the spider avoids the risk of being squashed by an unwilling blood donor.

More at: African Spider Craves Human Blood

Hooting Fiends Luring Dung Beetles To Their Deaths

Tool usage in animals is something I'm fascinated with. It seems to be considered advanced behavior and it's certainly intelligent on some level, but I would really like to know how biologists define tool usage. My working definition is using a foreign object for something other than its intended use - for example, using a rock to break open a shell or a reed to suck termites from a mound or a dolphin protects its nose by wearing a sea sponge.

Is the weaving of a web by a spider tool usage, or the hidden door behind which the trapdoor spider hides? Now owls have joined the tooling animals with their interesting bug-luring dung usage that is almost like a primitive kind of farming.

Burrowing owls' habit of bringing mammal dung to their burrows is an example of tool use, researchers say. The dung attracts beetles, an important part of owl diets, the scientists have found.

More at: Owls use tools: Dung is lure for beetles

Glow-In-The-Dark Pumpkins

I first heard about this extraordinary toxic cleanup method on the Earthwatch Radio podcast earlier in the month. Sortof like the poisonous but beautiful oleander flowers that help clean up the carbon dioxide and toxic fumes along the freeways, scientists are increasingly turning to horticultural methods to handle managemen of toxins. Most recently, there's been some research on using squashes to extract nasty toxins from the soil.

Some toxic chemicals that were taken out of production during the 1970s are extremely persistent and still linger in the environment. In North America, some places are still tainted by the pesticide DDT and industrial chemicals known as PCBs. Scientists are testing plants to see if they can clean up these places, and they say pumpkins and zucchini do the job pretty well.

More at: A Helpful But Hazardous Harvest

Posted by sorsha at October 31, 2005 10:01 PM