Radiant arachnid romance
Friday, 26 Jan 2007 00:01
Cosmophasis umbratica: Not interested in non-fluorescent females
It may be invisible to humans, but spiders from the world's largest arachnid family are making good use of ultraviolet light to attract mates, a new study says.
The ornate jumping spider cosmophasis umbratica employs fluorescent mouth parts to excite the opposite sex' interest.
Both male and female jumping spiders have excellent eyesight and are highly-sensitive to UV light, the authors of today's study, published in journal Science, write.
The spiders have photoreceptors in and around their mouths that are able to detect UV wavelengths in a similar way employed by parrots and marine invertebrates.
While males have UV reflective patches on their face and body, female spiders' body parts contain a UV-excited bright green fluorescence that is unique to them.
When researchers placed spiders of both genders in environments bathed in UV light, male spiders actively courted females by adopting courtship postures.
But male spiders then responded to non-fluoresced females by largely ignoring them, the authors write.