RSS Feeds

Email a Friend Printer Friendly

Computer search for Billy Bumblebee and Friends

June 20, 2001

A fat bumblebee lies sedated beneath the stereo magnifying glass, its right wing pinned between a glass prism and a slide glass. A bright lamp illuminates the scene so that the veining of the wing is clearly visible on the display of the digital camera attached to the tube. „First we have to photograph the wing," Dr. Tom Arbuckle explains, pressing the shutter release. „The picture quality of an ordinary camera is perfectly adequate,„ he adds. He stores the photo in the adjacent laptop. With a few clicks of the mouse Dr. Arbuckle, who works at the Bonn Institute of Computing Science III (Director: Prof. Armin Cremers) then takes the first step in the process of analysis - processing the picture.

„In each wing there are three easily recognisable cells whose shape enables us to determine the species," Dr. Arbuckle continues. Taking these cells as the basis, the computer searches for more veins. So that it knows where to concentrate its search, it accesses typical wing images stored in its memory. From the data found by the software it then condenses the essential features - in other words the essence of the bumblebee's wing, reduced to a few figures, data on the size of the surface area and angles. „We then feed our analysis program with these results," Dr. Volker Steinhage explains. Three minutes after pressing the shutter release we know that the bee belongs to the species bombus terrestris.

„Even in Germany with its long tradition in the classification of bees surprises are still
possible," says Dr. Stefan Schröder, an agricultural scientist. He knows what he is talking about. While he was still working for his diploma at the Institute of Agricultural Zoology and Bee-keeping (Director: Prof. Dieter Wittmann) he was involved with bumblebees. „For example, we have only recently discovered that a particular species of bumblebee in fact consists of four different species, which even experts can hardly distinguish from each other.„ Dr. Schröder's idea therefore was to get the computer to do this job. Together with Dr. Volker Steinhage from the Bonn Institute of Computing Science he made a draft version of a suitable program. The project, involving a team of Bonn computer specialists and agricultural scientists, was then funded by the German Research Association (DFG) and the Federal Ministry of Education, Science, Research and Technology. The results are impressive: in 97 to 99 per cent of cases the software is correct - even experts in the classification of

bees, known technically as taxonomists, cannot score better than this. The ground bumblebee, which has revived by now, is not impressed. It gives itself a thorough grooming and flies off.

„This is one of the advantages of this approach," Dr. Schröder explains. Whereas in the conventional method the insect dies, in this new method it is sedated by being briefly placed on ice. What is more, the classification can take place outdoors. It does not need to take place in the lab after the bee has been caught. „However, it is also possible to photograph the wings in the field during the day and get the computer to analyse the data overnight." Yet the human taxonomist is not entirely dispensable: for the training phase the computer requires about thirty insects of the same species which have been unambiguously identified.

Classifying bees is not an end in itself: bees pollinate about three quarters of all plants, thereby forming the basis for their reproduction. However, environmental pollution and diseases have already led to a situation where many species of bees are on the verge of extinction - with terrible consequences for agriculture, which is threatened with harvest failures running into the billions. In the US whole plantations are now being pollinated by artificially bred colonies of bees. The researchers therefore wish to trace the spread of different species of bees, partly to discover precisely which influences encourage or endanger their existence.

But taxonomists are thin on the ground, since all over the world they are not being replaced - mainly because there is no money to be made with their expertise. „Most German bee experts are basically teachers, clergy or pharmacists. They do it as a hobby," Dr. Schröder reveals. And for many groups of bees there are only one or two real specialists nationwide. „If this trend continues, our taxonomists will die out faster than our bees."

Bonn, Universitaet