March 14, 2007—If whip spiders could use cell phones, you
can bet they'd be on a family calling plan.
That's because at least two species of these amblypygids—a type of arachnid—like to keep in constant contact with mom and siblings for about their first year of life, according to new research.
(Related photo: "Rare Baby Spiders Ride Mom's Back" [January 27, 2006].)
Young whip spiders gather in social groups and are constantly waving their long, flexible, whiplike front legs, said Linda S. Rayor, a behavioral ecologist at Cornell University and lead author of a new study in the Journal of Arachnology. The arachnids' namesake appendages are covered in hairs that are sensitive to chemical signals and vibrations, she noted.
When mom comes over to a group, as seen in the above image, she strokes her young with her whips. The youngsters respond by orienting themselves toward her and more actively waving their whips.
"It's almost like seeing a big interactive family together at dinner—there's constant movement and reaction to others in the group," Rayor said.
The news comes as a surprise, because amblypygids have long been thought of as solitary hunters that can get "really feisty as adults" when they encounter another of their kind, she said (see photos of wind scorpions, a related, and aggressive, arachnid species). With the whip spiders in her study, Rayor noticed the first evidence of aggression when the arachnids reached sexual maturity, at about 12 to 14 months old.
Rayor and colleagues observed the behavior in two species—the dime-size Phrynus marginemaculatus from Florida and the larger Damon diadema native to Tanzania—only in the lab.
The researcher thinks it's possible the younger animals' peaceful social behavior has been missed so far in the wild, because juvenile whip spiders can be incredibly hard to see. They blend in well with their forest setting and hide easily in cracks.
Amblypygids are "pretty common in tropical regions all over the world," Rayor noted. "But they are strictly nocturnal hunters.
They hide very effectively during the day. They're flat little devils."
More Photos in the News
Today's 15 Most Read Stories
Free Email Newsletter: Focus on Photography