Study: rare crab spider can change colors

"Overall, it has been a fascinating animal to study," said spider expert Gary Dodson.

By Brooks Hays

MUNCIE, Ind., April 7 (UPI) -- Chameleons aren't the only animal changing colors. Adaptable camouflage is a rare trait, but it's not exclusive to reptiles. As a new study reveals, an arachnid called the whitebanded crab spider (Misumenoides formosipes) can also swap costumes to better blend in with its surroundings.

The crab spider's color-changing abilities have been detailed for the first time in a new scientific paper, published this week in the journal Ecological Entomology. Scientists knew the whitebanded crab spider could switch between shades of white and yellow, but the process had yet to be formally documented.


"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 Ball State biology professor, explained in a press release. "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."

By blending into the hue of their favorite flower pedals, the spiders can remain mostly unseen -- helping them avoid predators and more easily sneak up on prey.


Dodson and his research partner Alissa Anderson, a alumnus of the biology department's masters program, used Adobe Photoshop software to record and measure the color changing process of various female spider specimens (male spiders can't change colors). They found white spiders had a much easier time switching to yellow than vice versa.

The new study also documented the species unique sexual dimorphism and reproductive behaviors. Females are roughly 20 times larger than their male counterparts. But males outnumber female specimens. They often gather in large numbers to compete for the sexual rights to maturing female.

"We determined that first to arrive, body size and previous contest experience are predictors of who will win the fights and remain close to the female," Dodson explained. "We also were able to document another surprising behavior for these spiders -- that the males drink nectar. This has since been determined for several other species. Overall, it has been a fascinating animal to study."

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