Spiders that die of fright
And what are they mortally afraid of? Their own bigger relatives.
If you have a paralyzing fear of spiders, here's a Halloween treat: Some spiders can be literally scared to death by their own eight-legged relatives.
Matthew Persons, an arachnid researcher at Susquehanna University in Selinsgrove, Pa., has watched it happen with wolf spiders, a vast, voracious family of creepy-crawlers that help keep harmful bug populations in check.
Persons wondered why wolf spider species bother leaving silk thread trails, since they live on the ground and don't make webs. It turns out these "draglines" are loaded with chemical cues and clues that make potential prey - including other wolf spiders - very afraid.
To study this, Persons and some of his students put small wolf spiders in individual enclosures with yummy insect meals. Then they introduced silk and feces from a bigger wolf spider species, either intermittently or permanently.
Over 21 days, the itty bitty spiders that were constantly exposed to hints of a predator stopped eating, lost weight and, finally, gave up the ghost.
Persons was surprised to find that spiders can be scared to death "even when the predator isn't present!"
His research has also shown that silk trails and droppings contain information about what and when the spider last ate. Using these clues, a potential prey spider could deduce how hungry the Big Guy is, what kind of bug he's in the mood for - and how scared to be.
Persons spends $3,000 a year on crickets to feed his spiders, and he is passionate about their biological importance.
Spiders, he says, can help answer questions about "sexual selection, foraging strategies, predator-prey interactions, communication, parental investment, population biology," and food chains.
Oh, and one more: "Cannibalism."
- Marie McCullough