PET reptiles and amphibians in the US are being killed by kindness. Many die
of poisoning after eating fireflies captured by their owners.
Fireflies of the genus Photinus contain potent toxins called lucibufagins, as
well as light-emitting luciferins. Tom Eisner, a chemical ecologist at Cornell
University in Ithaca, New York, says a North American firefly is 鈥渁 lethal
glowing pill鈥� containing about 90 micrograms of the toxins. Fireflies don鈥檛 need
to flee from their predators because their toxins act as a deterrent. This makes
them easy to catch鈥攊ndeed, trapping them is a traditional summer sport for
many children.
An estimated 20 million Americans now keep reptiles or amphibians, and some
fireflies are being fed to pets, with dire consequences. In this month鈥檚 Journal
of Chemical Ecology (vol 25 p 1981), Eisner reports that a 100-gram Australian
Pogona lizard, known as a 鈥渂earded dragon鈥�, turned from brown to black and died
after eating a single firefly. 鈥淭hat鈥檚 a big lizard,鈥� he says. Eisner adds that
no-one has tested European fireflies for the toxins.
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The problem has grown because the large number of imported species being kept
as pets would never encounter Photinus fireflies in their natural environment.
Eisner鈥檚 casualty list includes White鈥檚 tree frogs from Australia and an African
chameleon. Many reptiles were fed fireflies by their owners, but some caught the
insects themselves.