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The case of the vanishing taxonomists Add to ...

On July 26, 1999, police in the English Channel town of Worthing broke into a house and found the bludgeoned body of Jean Barnes, an 87-year-old spinster. Miss Barnes had not been missed until a neighbour realized that she had not seen her for a while, and called the police. They found her under a blanket on the floor, obviously dead for some time.

To find out how long, police called in the bug man, and with that call set in motion a series of events that helped to illuminate much more than the causes of a crime.

Henry Disney, a Cambridge University researcher and former medical entomologist, is the leading world authority on scuttle flies, also sometimes known as coffin flies because some species breed in human corpses. When they do, the stage of their life cycle can establish the time of death.



What's at stake is much more than helping to solve murders.


Dr. Disney examined scuttle-fly larvae from the body, and said the victim had been dead for two weeks. But a problem soon cropped up.

Police recovered a note, purportedly from Miss Barnes, cancelling her milk delivery and dated after the time of death set by Dr. Disney. Thinking he must be wrong, they called in bug man No. 2.

This second expert, an accredited forensic examiner, looked at the larvae and said death had occurred even earlier - a full month before the date on the note. Perplexed, the detectives summoned yet another entomologist.

This one checked out both reports and said Dr. Disney's was correct and the second one was nonsense: Not only had it got the insects' species wrong, but the genus too.

With Dr. Disney's dates re-established, the police took another look at the note and solved the case.

The point, though, is that Dr. Disney's dates had been challenged at all. For the Barnes case revealed much more than a bungled scuttle-fly ID.

That someone licensed to interpret insect larvae - the second "expert" - could make such a blunder was an example of a larger crisis that Dr. Disney and other scientists on both sides of the Atlantic have identified: the dwindling of a class of expert and a store of expertise.

What's at stake is much more than helping to solve murders. It's the ability of science to assess the state of life on Earth at a moment of whirlwind change - as new species are discovered and others go extinct.

A THREAT TO SCIENCE

The science of describing and naming species - of saying what they are - is called taxonomy. A taxonomist is an expert in a taxon - a group of plants or animals. In the classical model, a taxonomist scrutinized the physical traits of a specimen, said where it belonged in the system of classification and named it.

In the words of Harvard University's E.O. Wilson, a leading figure in contemporary biology, "master taxonomists" are a breed that is "fading from the scene. They die and are not being replaced."

Known internationally as the "taxonomic impediment," this problem is a rising issue among those struggling to understand biodiversity. In Britain, the Natural History Museum will deliver an assessment of the state of taxonomy at the end of this month - 18 years after a House of Lords committee first identified the decline in taxonomic research as "a threat to the science underpinning conservation."

The morphological taxonomist, engrossed in a single group and identifying its members by visual inspection, is increasingly an emeritus professor or someone near retirement. Younger scientists are drawn to molecular taxonomy, where powerful new techniques in the study of DNA have revealed interspecies connections never before suspected.

Such advances, including the Canadian-pioneered use of DNA barcodes to identify species, while undeniably useful, are "not a replacement for the [traditional]taxonomist," says Gary Saunders, who holds a chair in Molecular Systematics and Biodiversity at the University of New Brunswick.

"At times, the DNA-generated answer is wrong," Prof. Saunders says. "A trained taxonomist can look at a molecular result and know that there is cause to question the outcome."

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