Natures wonders: plant dead bee scent attracts flies (Introduction)

by David Turell , Thursday, October 06, 2016, 20:54 (2968 days ago) @ David Turell

A neat trick to get pollination for a plant:-https://www.newscientist.com/article/2108328-flower-hijacks-the-fragrance-of-attacked-bees-to-imprison-flies/-"Stop and smell the dying bees. The scent of a South African plant mimics the chemicals honeybees release when they're under attack.-"Scavenging flies on the lookout for a meal are then tricked into pollinating the plant's flowers.-"Many plants attract insect pollinators by exuding substances meant to mimic the sexy smell of potential mates or the alluring aroma of rotting flesh.-"Dötterl and his colleagues focused on solving the mystery for Ceropegia sandersonii, a South African plant that produces “pitfall flowers”, umbrella-shaped blossoms that keep pollinators trapped within their petals for about a day, before releasing them, now packed with pollen.-"To identify the plant's pollinators, the team gathered the insects they found imprisoned within its flowers. The most common was a type of small fly that dines on the drippings left by spiders as they kill and consume honeybees.
The team wondered if the plant could be exploiting the fly's culinary preferences to bait the insect.-“'What does a honeybee eaten by a spider and this flower have in common?” Dötterl asks.
To find out, the scientists simulated an attack by squeezing the honeybees with their fingers or poking them with a narrow glass cylinder, then collecting the defensive compounds the bees released. The team also extracted the chemicals given off by the plant, and found several compounds in common.-"Flies can perceive about half of those compounds, as subsequent experiments showed.
When the researchers left vials containing a blend of four of the overlapping substances outside, they lured in about half a dozen flies each in under an hour, while similar control vials of acetone were left alone.-“'They really look for a combination of compounds,” Dötterl says, referring to the scavenging flies. That makes sense because the individual chemicals are common in nature - many plants emit one or two of them - but the mixture is unique. “We found no other organism, other than the honeybee and this flower, which releases all four compounds together,” Dötterl adds.-"The team's use of multiple methods provides convincing evidence for how the flowers attract the flies, says Manfred Ayasse at the University of Ulm in Germany.
“It's a new fascinating example of chemical mimicry in plants that try to attract pollinators, and try to cheat them,” Ayasse says.-"It's also a good example of an intricate pollination system, says Jeremy McNeil at Western University in London, Ontario.-“'It goes to show that there are many ways to get a pollinator,” McNeil says. “The more we look, I think we're going to discover more and more.'”-Comment: How did chance evolution make this work? I have no idea, but the arrangement is very complex. Without pollination this plant won't survive. Let's assume this fly was pollinating but not often enough. To make the scent the plant had to know the flies' preferences in meals. How did it learn that? Not trial and error as Darwin might suggest. Saltation.