A group of scientists co-led by University of Pittsburgh biologists Dr Nathan Morehouse and Dr Daniel Zurek has found that spiders in the American genus Habronattus see in three color channels, as most humans and other primates do.
Adult male Habronattus coecatus jumping spider in Nashville, Tennessee. Image credit: Ryan Kaldari.
Dr Morehouse, Dr Zurek and their colleagues found that the principal eyes of Habronattus spiders see in red, green, and UV.
Their secret is a filter that converts some green-sensitive cells in their eyes to seeing red, much like a pair of sunglasses.
“The eyes of jumping spiders could not be more different from those of butterflies or birds, and yet all three tune the color sensitivities using pigments that filter light. It’s actually a pretty clever, simple solution with a big payoff,” said Dr Morehouse, senior author on the study published in the journal Current Biology.
The ‘spectral filtering’ the team discovered had never before been described in any spider. That makes this visual strategy a remarkable example of evolutionary convergence.
“One fascinating thing about the trichromatic area in these spiders’ retinas is that it is very restricted in field of view, which means they’d have to scan scenes ‘line by line’ to accumulate color information,” Dr Zurek said.
Earlier behavioral tests done by the scientists showed that Habronattus spiders could see in color. In their new study, they carefully examined structures within the spiders’ eyes to understand how.
The scientists now plan to explore the role that color vision may have played in generating the diversity of these spiders over evolutionary time.
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Daniel B. Zurek et al. 2015. Spectral filtering enables trichromatic vision in colorful jumping spiders. Current Biology, vol. 25, no. 10, pp. R403-R404; doi: 10.1016/j.cub.2015.03.033
