James L. Fuller
(Evolutionary Primatology, Ph.D.
in progress)
Vocal
communication in blue monkeys (Cercopithecus mitis stuhlmanni): form,
function, phylogeny, and sexual selection.
In primates, vocal communication is
a complex and
fundamental component of most intra-group, inter-group, and interspecific
interactions. Considerable research across numerous taxa
has examined form, function, and variation of vocal behavior, as well as
various ecological, evolutionary, and ontogenetic factors. The relative influence
and interactive effects of these, however, remains unresolved, as does the
degree to which observed vocal patterns may be as much influences on social
dynamics and phylogeny as they are consequences.
My
research seeks to improve understanding of the role vocal signals play in
shaping community structure, behavior patterns, and responses to ecological
conditions, and to provide quantitative measurements that
will contribute insight into primate sociality, evolution, and cognition.
MY RESEARCH EMPHASES:
FORM: Blue monkey
vocal behavior includes a variety of stereotyped signals. I am developing the first study to comprehensively
catalogue, describe, and characterize the full vocal repertoire of this
species. This involves analyzing hours of field recordings using spectrographic
analysis to provide quantitative description of
acoustic properties of each call type.
Variation within signal types can then be examined in regard to within-individual, between-individual, and between-context
differences.
FUNCTION:
The function of a particular signal is typically inferred by examining
attributes of the signaler, the context in which the signal occurs, acoustic
characters of the signal, and the behavioral response by receivers. I use both
naturally occurring vocalizations as well as playback experiments to collect
these data. I examine the age, sex, and social class of signalers as well as
the social and ecological context(s) in which calls are made. I also examine
location of the signaler relative to home range, core area, territory, and
other animals. Using playbacks of known individuals, I measure responses to
signals in regard to attention, movement (toward or away), and likelihood of
engaging in or refraining from other behaviors (e.g. feed, travel, copulate) in
the period after the signal. Controlling the content, timing, and focal target
of signals allows regression of vocalizations, individual responses, and
socio-ecological context.
PHYLOGENY:
The degree to which a speciesÕ repertoire reflects adaptations specific to its
current ecological context versus its lineage is often difficult to assess. I
will compare vocalizations from other populations of blue monkeys (e.g. Gombe, Ngogo) to those from the Kakamega population of blue monkeys, and then examine these
in relation to vocalizations by a population of a closely related subspecies,
SykesÕ monkeys (C. mitis
albogularis). This will allow me to determine the
degree to which the vocal repertoire of this species varies within and between taxa.
SEXUAL SELECTION: The vocal repertoire of adult male blue monkeys is fundamentally
different from that of females and juveniles. While juvenile males share a
vocal repertoire with juvenile and adult females of approximately 15 discrete
calls, adult resident males use only 4 calls, each of which is substantially
different from any call made by the other age-sex classes. I am investigating
the ontogeny of the male repertoire and, using observational, playback
experiment, and spectrographic analysis, will explore the mechanisms of sexual
selection at work in shaping this divergence in repertoire.
Publications:
Cords M, Fuller JL. (in press). Infanticide in blue monkeys (Cercopithecus mitis stuhlmanni) in the Kakamega
Forest, Kenya: variation in the occurrence of an adaptive behavior. International Journal of Primatology.
Criswell AM, Fuller JL.
(2006). Learning adaptation in caged and enriched environments: thereÕs nothing
like a change of scenery. IBN. 15(2): 25-28.