Happy Halloween!



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The well-known hourglass marking of Latrodectus mactans, the black widow spider.
Happy Halloween!  Just for ringing the doorbell, I'm presenting you with these eight-legged treats!  Spooky you say?  I suppose it is a matter of perception, I think they are all lovely!  The black widow above has a potent neurotoxic venom, but her bites are rarely fatal for humans.  For insects that blunder into her web however, it is a different story.

The bolas spider below employs a different strategy.  She does not capture prey in a web, but rather forms her silk into a sticky blob on the end of a strand.  She swings this blob at moths that fly near enough to her.  To entice her quarry, she secretes a chemical that emulates pheromones that the moths use to attract mates.  She can even change the chemical signal to match the species of moths that are around.  I've never been able to decide which was cooler: the rodeo style hunt, or the complicated chemical mimicry.
A Mastophora species Bolas Spider hunts with a sticky blob on a silk strand.
 The bolas spider isn't the only spider with a unique method for capturing prey.  The net-casting spider spins a web that is not sticky but has a wooly texture which entangles insects.  It holds the web with its legs, and throws it down on unsuspecting critters that venture too close.

The wolf spider does not hunt with a web at all, rather they stalk their prey and pounce upon them.  Female wolf spiders carry their eggs with them, and when the young hatch, they continue to ride around on mom for a while.  Wolf spiders are frequent visitors in basements, where they eat many other arthropods that may be less welcome.  While a ball of baby spiders may sound like something out of a horror film, I find this parental care to be fascinating.  I'd even go out on an entomological limb and say that it's kinda cute!
Wolf spiders (Lycosidae) carry their young.
A Costa Rican net-casting spider in the family Deinopidae.

1 comments:

biobabbler at: October 31, 2012 at 10:04 AM said...

That is fascinating. I love the different hunting strategies. I'm SO going to tell people about that pheromone-producing cowboy spider--amazing!

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