Insect use of cantharidin as a defensive chemical is not unique to the Neopyrochroa beetles, Smedley noted. Some midges and males of other beetle species are attracted to cantharidin; they eat the compound, presumably for transfer to their mates at copulation.

"We aren't the first to prospect for useful compounds," said CIRCE-founder Eisner, who advocates "chemical prospecting" to explore and inventory undiscovered sources of potentially useful, natural compounds. "Here is a beetle that has become more intimately involved in chemistry, and it pays off for him. Insects' use of exogenous chemicals is almost certainly more widespread than we realize."

One mystery remains. The chemical ecologists admit that they're uncertain how Neopyrochroa beetles obtain cantharidin, although they suspect that the source is blister beetles. Newly emerged adult Neopyrochroa beetles do not contain cantharidin. But by the time adult beetles are caught in the field and subjected to mass spectrometry, they test positive for Spanish fly.

"We don't think they get it from French chemists," Eisner said.

'"/>

Contact: Roger Segelken
hrs2@cornell.edu
607-255-9736
Cornell University News Service
25-Jun-1996