ITHACA, N.Y. -- Studies at the Cornell Institute for Chemical Ecology (CIRCE) are showing just how resourceful male insects can be when they seek a mate.
In one species, the fire-colored beetle Neopyrochroa flabellata, the male entices the female by presenting her with a chemical offering, secreted from a gland in his head. Next, as described in the June 25 issue of Proceedings of the National Academy of Sciences (PNAS), the female samples and ingests the offering, and responds by yielding to the male's copulatory advances.
Much more of the chemical is transferred to the female beetle in the mating male's sperm package. And she, in turn, bestows the chemical on her eggs, which are protected by the chemical from predators. Without the chemical, fire-colored beetle eggs would be lunch for other insects.
"Protecting the eggs is clearly to the advantage of both parents," said Thomas Eisner, the Cornell University biologist who led studies reported in PNAS. "The male's strategy is to woo the female with a 'teaser' of the chemical, and to reward her with a massive nuptial gift if she accepts him for mating."
Describing the cleft-like organ in the male beetle's head where the enticing chemical appears, Eisner suggested that the insect is, in effect, saying: "I've got a lot more where this is from, but you can't have it until we mate."
And what is this enticing chemical, males of many species by now are wondering, and where can I get mine? According to the CIRCE biologists, the chemical is none other than cantharidin, or Spanish fly, the notorious aphrodisiac of human folklore.
Spanish fly and the insects that use it are the subjects of two related reports, prepared for CIRCE's series on "Defense Mechanisms of Arthropods" and published in the national journal. The authors are Eisner, the Jacob Gould Schurman Professor of Biology; Scott R. Smedley, a post-doctoral researcher in CIRCE; Daniel K. Youngs, professor of entomology at the Univers
Contact: Roger Segelken
Cornell University News Service