Saturday, 2 April 2016

Art and artifice

Orchids are a conniving species. They lure pollinators by creating clever disguises to mimic food, rivals, or even mates. Bamboozled insects then carry pollen from one flower to another – and so the clever orchid can reproduce.

Scientists have to be similarly cunning to study this ingenious species and have turned to models from a 3D printer. Canny researchers can now show how one particular orchid tricks fungus-seeking flies by mimicking the sight and smell of their favourite mushrooms.

As flowers have so many colours, shapes, and smells, it’s quite a task to specify what parts of a flower are actually attracting pollinators. Scientists are now tackling this problem by using artificial flowers. They add different odours to fake flowers can watch how a pollinator reacts to smell alone. In the past, such flowers were created of paper, cotton balls, or test tubes with cotton wicks.

But now they’ve gone one step further to study the Dracula lafleurii, a lurid specimen found in the cloud forest of Ecuador. (They're similar in their bloodthirsty colouring to the Dracula bella, pictured.) A single petal of this unusual orchid resembles the fungi that live nearby and so attract flies that come along, often to breed on the mushrooms. Imagine trying to ‘origami’ such a complex form, and in the damp forest, the paper would simply disintegrate. Instead, scientists engaged artist Melinda Barnadas to develop a technique for creating artificial Dracula orchids. Now, with the help of 3D-scanning, the team can print 3D gypsum moulds from which they manufacture silicone orchids in whatever colour patterns required.

The team set up the artificial flowers next to actual Dracula orchids in the cloud forest. They modified both the fakes and the real flowers, changing the colours and patterns, and adding or removing scents, according to a report in New Phytologist. They even made several “Frankenstein” flowers, pieced together from artificial and natural flower parts. Then it was time to sit down and watch to witness which blooms got more attention from the flies.

They concluded that orchids wanted a certain look and the right smell. Fake flowers attracted fewer insects than the real blooms. Only when the researchers applied scents from natural orchids were just as many flies attracted to the mimics as to the real flowers.

What a marvellous combination of art, artifice and science. Much like orchids themselves.

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