Pumilio

Society for the Study of Amphibians and Reptiles

Diel Activity Patterns of the Sympatric Poison Dart Frogs, Dendrobates auratus and D.
pumilio, in Costa Rica
Author(s): Brent M. Graves
Reviewed work(s):
Source: Journal of Herpetology, Vol. 33, No. 3 (Sep., 1999), pp. 375-381
Published by: Society for the Study of Amphibians and Reptiles
Stable URL: http://www.jstor.org/stable/1565634 .Accessed: 27/05/2012 23:43
Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at .
http://www.jstor.org/page/info/about/policies/terms.jsp
JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of
content in a trusted digital archive. We use information technology and tools toincrease productivity and facilitate new forms
of scholarship. For more information about JSTOR, please contact support@jstor.org.

Society for the Study of Amphibians and Reptiles is collaborating with JSTOR to digitize, preserve and extend
access to Journal of Herpetology.

http://www.jstor.org

V
Journalf Herpetology,ol.33, No. 3, pp. 375-381,1999
o
a
Copyright1999Societyfor theStudy of Amphibians nd Reptiles

Diel Activity Patterns of the Sympatric Poison Dart Frogs,
Dendrobatesauratus and D. pumilio, in Costa Rica
BRENT M. GRAVES
N
4
M
U
M
b
M
o
Departmentf Biology, orthern ichigan niversity, arquette, ichigan 9855, USA.E-Mail: graves@nmu.edu
o
a
ABSTRACT.-Activityf Dendrobates uratusand D. pumilio in northeasternCosta Rica was monitored at
45 minintervals throughout daylight hours on nine days in late-Juneand early-July1997. Activity of D.
pumilio peaked early in the morning, declined steadily to mid-day,then remained at a relatively low level
through the afternoon.Activity of D. auratuspeaked in early afternoon,and was more consistentthroughout
the day than was activity of D. pumilio. There was a clear peak in use of elevated perches by D.pumilio,
which occurred shortly after sunrise, although no such pattern was evident for D. auratus. A significant
positive relationship between rainfall and activity was evident for D. pumilio, but not for D. auratus.These
data demonstratedifferences in activity patternsbetween these congeners, in spite of many ecological similarities.
Frogs of the family Dendrobatidae are wellknown for theirbright colors, toxic skin secretions, association with tropical habitats, and
complex social behaviors (Pough et al., 1998).
Dendrobatesauratus and D. pumilio are two species from this family that are common in parts
of Central America (Savage, 1968), and have
been studied relatively extensively in the laboratory and field. Much of this work has focused
on territoriality (Bunnell, 1973; McVeyet al.,
1981; Forester and Wisnieski, 1991; Forester et
al., 1993; Baugh and Forester, 1994), reproductive biology (Wells, 1978; Limerick, 1980; Weygoldt, 1980; Donnelly, 1989a, b, c; Summers,
1989; Brust, 1993), and diet (Toft, 1980a, b, 1981,
1995; Taigen and Pough, 1983; Pough and Taigen, 1990; Donnelly, 1991; Caldwell, 1996).
An aspect of the behavior and ecology of
these species thathas received much less study
is their daily activity patterns. All but one species of the family Dendrobatidae are diurnal
(Savage, 1968; Myers et al., 1991). Although D.
auratus and D. pumilio are active throughout the
day, there appears to be temporal variation in
the extent of activity. In his study of D. auratus,
Dunn (1941) stated that "The greatest activity is
on mornings after rains."Jaeger and Hailman
(1981) found that D. auratus on Barro Colorado
Island, Panama exhibited a bimodal activity pattern, with peaks in the early morning and late
evening. Bunnell (1973) suggested that the most
intensive period of calling for D. pumilio is between 0600 h and 1000 h, but no data were reported.
I studied activity patterns of dendrobatids at
a site where D. auratusand D....