The Loh Down On Science

Black widows may be more calculating than you think!

Are black widow spiders sensible managers?

This is Sandra Tsing Loh with the Loh Down on Science.

Meet David Nelsen, from Loma Linda University, in Southern California.  He pestered wild-caught black widow spiders to test their fight or flight response.  How?  By poking them with a soft-tipped probe.  They just scurried off.  Then he prodded them incessantly, once a second for a full minute.  They just ran around and shot silk in defense.  But when he pinched them?  They sank their fangs into the probe.

He then pinched his subjects while presenting a film-covered tube to bite into.  The tube collected any injected venom.  And?  Most bites were dry warning nips!  When they weren’t?  The spiders injected twice as much juice when pinched in the body than in a leg.  And they metered out half-doses after they’d already delivered a good fangful.

So the spiders judge the threat level and respond prudently.  Venom takes precious energy to produce.  Why fight and risk injury when you can flee? 

Black widows manage their resources:  It's how they keep that hourglass figure.

 

***** For more 90-SECOND SCIENCE FACTS, click here.*****

The Loh Down on Science is produced by LDOS Media Lab, in partnership with the University of California, Irvine, and 89.3 KPCC. And made possible by the generous support of the Gordon and Betty Moore Foundation.


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