News

In incubation rooms filled with the smell of cornmeal and molasses, Indiana University biologists nurture millions of fruit flies from squirming larvae to winged adults.

These gnat-like insects – pests in many Americans' kitchens – are the sole product of what is considered the world's most comprehensive repository for mutant fruit fly strains beloved by genetics researchers.

The tiny insects, however, are making outlaws of their keepers.

Every time researchers send vials of the living flies, their eggs or larvae to overseas scientists, they break an international postal agreement that forbids mailing most live insects among about 190 participating nations.

“We can't stop supplying scientists with the things they need to do their research. At the same time, we don't want to be in violation of the law,” said Kevin Cook, co-director of the Bloomington Drosophila Stock Center.

The postal accord was written early in the 20th century before fruit flies earned a key role in genetic research. It says only “live bees, leeches and silkworms” and “parasites and predators of injurious insects” can be sent overseas.

As genetic research heated up, however, so did demand for strains of fruit flies with mutations that influence a host of biological functions.

The fruit fly – Drosophila melanogaster – is easy to raise, has a short life span, giant chromosomes and reproduces quickly, enabling researchers to study mutations from generation to generation.

In 2003, the Bloomington centre mailed nearly 125,000 samples of fruit flies – about 43,000 of them to overseas labs. Last year, shipments rose about 20 per cent, Cook said.

Akhilesh Mathur, mail program manager for the Universal Postal Union, the Switzerland-based group that administers the rule, said the illegal shipments by the Indiana centre and its counterparts went undetected for decades.

Mr. Cook said he studied the rules and thought it was okay to ship the flies. He learned otherwise about two years ago, after postal inspectors returned a fly shipment destined for overseas.

He consulted immediately with U.S. federal officials to try to change the rule, which he feared could jeopardize the centre's growing work. And he continued to ship the flies to overseas labs.

Since 1987, when the fruit fly repository moved from the California Institute of Technology to Bloomington, the centre has grown from 1,675 fruit fly strains to about 20,000, with more than 10 million fruit flies on hand at any one time.

A dozen staff members raise successive generations of each strain in bottles, feeding them a sweetened corn meal mush that gives their incubation rooms a pungent smell. Biologists watch over five cultures of each strain.

Laurie Tompkins, who co-ordinates the National Institutes of Health's grant programs for fruit fly research, said the Bloomington centre is the world's premier repository for the insects and plays a key role in human genetic research.

“Every month, we gain some new insight from studies of flies that sheds light on human metabolism, biochemistry or some important function,” said Tompkins, who supports lifting the postal ban.

That change appears imminent. In September, after months of effort by U.S. Postal Service and State Department officials, the Universal Postal Union approved a proposal that Mr. Cook helped draft, and which permits mailing live fruit flies between nations.

The new rule is set to take effect in January, 2006, but the State Department has proposed accelerating it to this spring. The UPU's Postal Operations Council is expected to consider that proposal at its meeting in Bern this month.

If it is accepted, the member nations are expected to implement the change by June 1.