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Urban smells confound flower-seeking moths

Car exhaust and other urban fumes can disrupt moths’ ability to make their way to flowers, a new study reports.

“The flowers occur in patches that can be kilometers away, and these moths are almost at the edge of survival trying to find them,” said Jeff Riffell, a biologist at the University of Washington and the first author of the study, which appears in the journal Science.

The research focuses on the tobacco hornworm moth, which depends on nectar for energy. Nectar from one flower provides enough fuel for just 15 minutes of flying time, so “flying around is really energetically expensive,” Riffell said.

The scientists sampled flower scents and other odors with a sensitive mass spectrometer, and then used a wind tunnel to determine how different combinations of smells affected a moth’s ability to find flowers. They found that the moths did far better in rural environments than in urban and suburban ones.

But it is not just man-made odors that affect the moths. Scents from neighboring vegetation can be very disruptive as well, Riffell said.

Now the researchers are interested in studying the effects of urban scents on other major pollinators, like honeybees.

Flashing disco clam has mirror balls on its lip

Ctenoides ales is well-known to scuba divers, who call it the disco or electric clam for its mirror-ball luminescence. But few scientists had given it much notice until Lindsey Dougherty came along.

Dougherty, a 31-year-old integrative biologist and doctoral student at the University of California, Berkeley, says she fell in love with the clam the first time she saw one flashing at her in the waters off Indonesia.

Now, in the Journal of the Royal Society Interface, she and colleagues report that they have discovered the mechanism that causes the clam’s flash. The inside of the clam’s lip, it turns out, is full of nanospheres of light-reflecting silica; by contrast, the outside of the lip has no silica and is highly light-absorbent.

“So it furls and unfurls, creating two flashes per second,” Dougherty said.

When she presented the clams with artificial predators in the lab, she saw an increase to four flashes per second. The inside lip is particularly good at reflecting blue light – perfect for the ocean.

Now the question is why the clams flash at all. They may be using their flashes to attract prey, scare away predators or even “attracting each other to settle nearby,” Dougherty said.

She is also interested in studying the eyes of C. ales. Each clam has about 40.

– New York Times