Smells like aphids
27 Oct 2010 by Evoluted New Media
The orchid has come up with a clever trick to dupe hoverflies into laying their eggs in the flower and acting as a pollinator – smelling like a worried aphid.
The orchid has come up with a clever trick to dupe hoverflies into laying their eggs in the flower and acting as a pollinator – smelling like a worried aphid.
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Orchids emit pheromones and dupe hoverflies into pollinating them Credit MPI Chemical Ecology, Johannes Stökl |
Scientists from the Max Plank Institute for Chemical Ecology discovered that the Epipactis veratrifolia produced chemical substances that are usually emitted as alarm pheromones among aphids – alpha- and beta- pinene, beta myrcene and beta-phellandrene.
Female hoverflies like to lay their eggs near aphids – which act as perfect baby food for growing larvae – and mistake the ‘alarm’ for the real thing. When their eggs hatch, they’re doomed to death as there’s nothing for them to feed on. Meanwhile, the female has been duped into pollinating the orchid’s flower.
“We assume that the insects are not only deceived by the aphid alarm pheromones, but also fall for the aphid-like dark warts in the orchid’s flower,” said Bill Hansson, director of the Max Plank Institute.
The scientists also observed that male hoverflies were attracted to the orchids, hanging around the flowers in the hope they might be able to mate with the attracted females. Both male and female hoverflies attracted to the flower are rewarded with a small amount of nectar – but have been duped into acting pollen transmitter.
The orchid doesn’t mimic the alarm pheromone of just one aphid species say the scientists, as the amount of volatiles emitted by the aphids and the flower differ in amount and constitution. The volatile substances generate measurable electrical impulses in the hoverfly antennae and behavioural experiments show that these chemicals attract the hoverflies and encourage oviposition.
