Utetheisa ornatrix; adult (upper)
and larvae on a Crotolaria seed pod (lower); photos by Tom
Project Director: Thomas Eisner, Cornell University
Outside Collaborators: Scott Smedley and Athula Attygalle, Cornell University
Graduate Students: Carmen Rossini, Andrés Gonzalez, and Vik Iyengar, Cornell
Project Assistant: Maria Eisner, Cornell University
[Biennial Contents | Biennial 95-96 |
Thomas Eisner (Cornell Univ.) visited the Station
with graduate students, and his research partner, Maria Eisner, several times during
199798. A number of projects, all with a chemical-ecological focus, are underway.
The Ornate Moth. This moth (Utetheisa ornatrix,
see photos, this page)
is unusual in that it is entirely dependent on certain alkaloids (pyrrolizidine alkaloids)
from its food plant (legumes of the genus Crotalaria). Both sexes acquire the
chemicals as larvae and retain them through metamorphosis into adulthood. The female
invests her chemicals in the eggs, protecting these as a result, but depleting her own
alkaloidal supply in the process. To compensate for this loss she receives alkaloids from
the male with the sperm package. Individual females may mate with as many as 20 males,
thereby acquiring relatively massive amounts of alkaloids during their lifespan. This
study provides the first documentation of egg protection by biparental chemical endowment
in an animal.
Phengodid Beetle Larva vs. Millepede. The larva of Phengodes
laticollis kills the millipede Floridobolus penneri with an injection of
enteric fluid administered with its sharp, sickle-shaped mandibles. The infusion paralyzes
the millipede instantly, preventing it from discharging its defensive glands in response.
The paralytic agent remains unknown, but is of considerable, perhaps even medicinal,
potential (it could be the source of channel-active factors).
The Chemistry of Walking Sticks. Years ago
Eisners group characterized the defensive spray of the walking stick Anisomorpha
buprestoides. The chemical turned out to be a novel terpene (anisomorphal) of
extraordinary irritancy. This work prompted an investigation of the defensive fluid of
other walking sticks, resulting in the isolation of another repellent agent (quinoline),
not previously known from insects.
Chemical Prospecting. Eisners group continued its
search for new chemicals from organisms, with an emphasis on species from the Station. In
collaboration with chemists from Cornell the group is looking into substances from plants
and insects in hopes of discovering leads to medicinals, agrochemicals, and other
substances. Of particular interest is the search for new defensive chemicals from slug
"Dont Say Good Bye." A film by that
name, on endangered species, focusing on the photographs of Susan Middleton and David
Littschwager, produced by National Geographic Television, includes a segment filmed at the
Station dealing with Eisners work on "chemical prospecting." Eisner
introduced a showing of the film in Washington, D.C., in October 1997, at the AAAS
auditorium on the occasion of a "Biodiversity Forum" sponsored by the National
Academy of Sciences. The film subsequently received an Emmy award.
Biennial Contents | Top
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