RHYTHMIC ACTIVITY OF THE WEB-BUILDING SPIDER, AND ITS DISTURBANCE …
FIFTH INTERNATIONAL CONGRESS ON PHARMACOLOGY

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REPRINTED FROM
FIFTH INTERNATIONAL CONGRESS
ON PHARMACOLOGY
JULY 23-28, 1972
PRINTED IN U.S.A.
RHYTHMIC ACTIVITY OF THE WEB-BUILDING SPIDER, AND ITS DISTUR-
BANCE BY DEXTRO-AMPHETAMINE. Peter N. Witt, Charles F. Reed
and Robert R. Jackson, N.tC. Department of Mental Health,
Research Division, Raleigh, N. C. 27611, USA
Can analysis of drug effects on invertebrate behavior con-
tribute to our knowledge about a drug*s way of interfering
with central nervous system function? Daily construction of
the orb web by the spider Araneus diadematus Cl. can be re-
garded as a rhythmic process, where the same movement pattern
is repeated many times. Early observations (Witt, 1949) had
established that webs built by spiders several hours after the
oral application of 300 mg/kg d-amphetamine compared to con-
trols had significantly increased irregular central radial
angles and spirals. No data have so far been available on the
timing which underlies construction of a regular or irregular
web. By examining the microscopic structure, amphetamine webs
can be shown to possess in addition to many elaborate “normal”
thread connections, some connections which are not securely
fastened. Time-sequence analysis of the construction pro-
cess from movies produced for control animals a relatively
constant figure for the laying of each spiral section, while
spiders after d-amphetamine alternated erratically between
rapid and slow periods. This as well as the observation that
all probing movements were preserved leads to the conclusion
that the drugged spider remains undisturbed in each subprogram
of the motor pattern, but is made incapable of properly timing
the rhythmic process of repetition. (Supported in part by
NSF grant GB-6246.)