FLYING foxes in Queensland are being born with developmental abnormalities, and biologists suspect that chemicals are to blame. Because of habitat loss, pregnant bats may be feeding on fruit sprayed with pesticides, or on plants that naturally contain teratogenic chemicals.

In the past few months, spectacled flying foxes (Pteropus conspicillatus) have been born with extra digits, enlarged heads and cleft palates, and have died shortly after birth. Usually two or three bats with developmental defects are seen each season. But this year at least 50 have been spotted, says Hugh Spencer, who heads the Tropical Research Station at Cape Tribulation, part of the Wet Tropics World Heritage site.

The lowland forest surrounding the World Heritage area has been reduced by over one third in the past 15 years, and some upland forest is also being lost. Spencer believes this shrinkage may be forcing the bats to turn to food that is causing the birth defects. "The population is clearly under stress," he says.

Habitat clearance may also be at the root of a second problem. Orchards in southeast Queensland are suffering their worst-ever raids from grey-headed flying foxes (Pteropus poliocephalus), forcing farmers to shoot or electrocute the animals. Richard Armstrong, a fruit farmer and chair of Queensland Fruit and Vegetable Growers, says his farm lost three-quarters of its peach and nectarine crop.

Because neither the spectacled nor the grey-headed flying fox is listed as endangered or vulnerable, farmers can apply for permits to kill the animals if they cause too much damage. Population counts organised by Stephen Garnett of the Queensland Department of the Environment and Heritage in Cairns suggest that numbers of spectacled flying fox are holding steady. But in a report that has yet to be published, Garnett and Spencer argue that the spectacled flying foxes, which help pollinate trees and disperse seeds, need protection because they are vital to the health of the rainforest.