Stinking beauty betrays dung beetles.

Many blossoms offer sweet fragrances that attract pollinators, not to mention young lovers, but a purple flower in Borneo takes a different tack. It gives off an odor convincing enough to win the attention of dung beetles.

This plant provides a rare example of pollination machinery specialized for beetles that eat dung, says Shoko Sakai of Kyoto University in Japan. Other plants stink, but they usually attract flies or a mix of excrement lovers. The flower in Borneo, however, relies mostly on small Onthophagus beetles, she and Kyoto colleague Tamiji Inoue report in the January American Journal of Botany.

The plant's name, Orchidantha inouei, honors the senior author, who died in a plane crash at the research site before publication. Orchidantha belongs to the same taxonomic order as gingers, bananas, and bird-of-paradise plants. The order includes plants that command the pollination services of birds, bats, tree shrews, and even lemurs.

Orchidantha flowers don't offer nectar but release their special fragrance from around 7:30 a.m. until midnight. To the human nose, the odor does not smell exactly like dung but "more simple," Sakai reports. It's not the strongest floral odor she's smelled, but she can catch whiffs of a blossom from about a meter away.

For more than 100 hours, the researchers watched or videotaped two Orchidantha patches. Flies and various other insects window-shopped, but only dung beetles crawled behind a floral screen to the reproductive structures. Out of 30 visits from Onthophagus, proposed as the major pollinator, the beetles brushed the female stigma in 18 cases. In 16 of those 18 cases, beetles brushed the male anthers and emerged from the flowers sporting white pollen.

The world would be less pleasant without the clean-up efforts of the 30,000 species of dung beetles, says Bruce D. Gill, a dung beetle specialist for the Canadian Food Inspection Agency in Ottawa, Ontario. Ancient beetles even cleaned up after dinosaurs (SN: 9/21/96, p. 186).

Some dung beetles shape their dung finds into lumps the size of croquet balls, with diameters 2 to 3 times the insects' body length, which they take home for the family. "When you see these beetles rolling a ball of dung along the road, it's pretty spectacular," Gill says.

The Onthophagus beetles that visit the Borneo flower don't roll dung but tunnel under fresh piles. There, a male and female work together to stuff an underground chamber with dung from above. It makes great baby food when eggs hatch. Adults also feed on dung, especially the fluids. "It's sort of a yogurt for beetles," Gill says.

Orchidantha disrupts this quest for dung. "The poor beetles are working hard to clean up the mess left by mammals and these flowers are fooling them," Gill grumbles.

Telling deceit from a subtle trade can be difficult, observes Gordon Frankie of the University of California, Berkeley. For example, some orchids look like female bees, and males trying to mate get covered with pollen. The male seems a clear loser, but evidence suggests that openings in his legs collect plant scrapings as raw material for manufacturing pheromones to attract a real mate. Frankie urges more research before concluding that the dung beetles gain no benefit from the flower.

"Nothing surprises me with pollinators," he says. New oddities surface, and familiar puzzles linger. Despite vital importance to humanity, he says, researchers are not even sure what animals pollinate the coffee plant.