This Camouflaged Spider can Change its Color
Camouflage is not exactly rare in nature, but active camouflage - the type that changes to reflect its surroundings - has always been an exceptionally rare and fascinating ability. Some fish, lizards, and cephalopods have this ability to a certain degree. Now we can add spiders to that list, after experts identified a species of crab spider than can slowly change its colors to match its background when hunting.
"This species of spider crab is one of the few that can reversibly change their body color in a manner that to the human eye results in a match to the flowers on which they ambush prey," Gary Dodson, a biologist at Ball State University, explained in a recent statement. "We knew that females, but not males, can switch between white and yellow depending on the background. But we did not how quickly that happened."
Dodson and researcher Alissa Anderson are the first scientists to measure the rate of color change in Misumenoides formosipes, commonly known as the whitebanded crab spider. The results of their work was published in the journal Ecological Entomology. (Scroll to read on...)
According to the study, the pair used Adobe Photoshop software to measure the rate of color change as the spiders moved from one flower to another of a different hue. They found that unlike chameleons or cuttlefish, which are famous for their stunningly fast and accurate active camouflage abilities, these spiders can take three to nine days to undergo an adequate change.
What's more, when given a choice between changing their color or simply moving back to a habitat that they'd better blend into, the spiders will choose the latter every time. One possible explanation, the researchers suggest, is that swapping between white or yellow can be rather exhausting for the arachnid.
Still, as the spiders tend to live among either yellow or white flowering plants exclusively, the limitations of their intriguing ability are not noticeable. In fact, males of the species, which cannot change color, have a hard time finding mates at all.
"They can't see the females, yet they find them at a rate that random searching could not explain," Dodson added. "We documented that the males will optimize their searches by moving toward the odor of a flower species on which sedentary females hunt for prey."
In past work, Dodson had observed how the males, desperate to find a mate, will gather en-masse around the right kind of flowers, often fighting to the death amongst one another for the privilege to even be near an elusive female.
"Overall, it has been a fascinating animal to study," he said.
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