Caltech and UCSD Scientists Establish Leech as Model for Study
of Reproductive Behavior PASADENA, Calif.—Researchers at the
California Institute of Technology (Caltech) and the University
of California, San Diego (UCSD) have discovered that injecting a
simple hormone into leeches creates a novel way to study how
hormones and the nervous system work together to produce
species-specific reproductive behavior. A paper describing the
work appears in the March 11 online edition of the journal
Current Biology. Daniel Wagenaar, Broad Senior Research Fellow
in Brain Circuitry at Caltech and first author of the paper,
found that injecting a particular hormone into a medicinal leech
(Hirudo verbana) induced a series of movements that closely
mimic natural reproductive behavior, including a stereotypical
180-degree twisting of the body. Wagenaar's studies were
initiated at UCSD. The twisting, which occurs with a period of
approximately five minutes—making it one of the slowest
behavioral rhythms ever discovered, aside f