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The Orchid That Smells Like People

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Y:        Hey, Don, do you smell something?

D:        Like what?

Y:        It smells a little like body odor in here.

D:        Oh, that. It must be my orchid plant.

Y:        Your...orchid? Since when do orchids smell like people? Actually, I take that back. I have heard about orchids that smell like rotting meat and orchids that smell like fish to attract pollinators.

D:        That's what this orchid is doing. This is a small northern bog orchid, and it lures in tiger mosquitoes by giving off an odor that has chemicals found in human body odor.

Y:        So the orchid is trying to trick mosquitoes to land on it by making them think they're about to land on a person.

D:        And, instead of human blood, the mosquito gets pollen that it can move to another orchid.

Y:        So how did scientists know it was the body odor chemicals that mosquitoes were responding to?

D:        Well, after collecting the orchids' scent in airtight plastic bags and analyzing what chemicals were in it, scientists collected a sample of mosquitoes buzzing around the site. Then they delivered pulses of the different chemicals they found in the orchid scent. The body odor chemical set off electrical activity in the mosquitoes' antennae, implying that it's what attracts them.

Y:        When you say body odor, you just mean a human‑like smell, right? Not necessarily a bad one?

D:        Yup. And humans can barely smell it, anyway.

Y:        So what you're telling me is that the odor I smell right now isn't coming from your orchid.

D:        Well... I did just get back from a jog...
Orchids

Some orchids have a very strange smell. (Calvin Teo, Wikimedia Commons)

It might sound strange, but some orchids smell like people. Others smell like rotting meat or fish to attract pollinators.

One orchid that smells human is the northern bog orchid. It lures in tiger mosquitoes by giving off an odor that has chemicals found in human body odor.

The orchid is trying to trick mosquitoes to land on it by making them think they're about to land on a person. And, instead of human blood, the mosquito gets pollen that it can move to another orchid.

In order for scientists to know it was the body odor chemicals that mosquitoes were responding to they collected the orchids' scent in airtight plastic bags and analyzed what chemicals were in it. Then they collected a sample of mosquitoes buzzing around the site.

After this they delivered pulses of the different chemicals they found in the orchid scent. The body odor chemical set off electrical activity in the mosquitoes' antennae, implying that it's what attracts them.

 

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