PORTLAND, OREGON—Orchids are masters of deception. To lure potential pollinators, some resemble nectar-laden flowers, yet offer no sweet reward. Others smell like rotting meat. Still others look and smell like female insects. Now, sensory biologists have discovered orchids that emit an odor just like the human body. Their target: tiger mosquitoes. Although mosquitoes are considered poor pollinators, Platanthera obtusata, a bog orchid common in the United States, seems to rely on the blood-sucking insects for reproduction. The orchid rarely interbreeds with its closely related Platanthera cousins, which often live alongside it in the same bog. As a result, sensory ecologists suspected each species remains true to its own kind by attracting different pollinators. To test this idea, the researchers put air-tight bags over several kinds of orchids to collect their odors, and then analyzed each one’s chemical components. Along with components common to many flowers, P. obtusata gives off some chemicals found in human body odor, the researchers reported here today at the annual meeting of the Society for Integrative and Comparative Biology. Although the orchid’s “body odor” is barely detectable by humans, it does set off electrical activity in the mosquito’s antennae, indicating it may very well attract the insects. To verify this attraction, the researchers are carrying out behavioral tests. They suggest that such studies could lead to the identification of natural chemicals that could be used as bait in mosquito traps.