Understanding the Pair
Bond in Brown Titi Monkeys (Callicebus
brunneus):
Male and Female Reproductive Interests
Close male-female bonds in
primates are thought to relate to three categories of sex-specific
benefits:
joint resource defense, male mating exclusivity, and the delivery of
male
services that increase female reproductive success. In addition to
documenting
the natural history of brown titi monkeys (Callicebus brunneus) at Los Amigos Research Center in
Amazonian Peru,
this thesis explores these three potential benefits by examining the
bonds
between pairmates of C. brunneus,
a predominantly frugivorous species characterized by strong attraction
between
the pairmates in each group. I studied seven sets of pairmates in a
Peruvian
rainforest, using observational sampling and playbacks of unfamiliar
calls
(simulating intruders) to quantify behavioral indicators of
pair-bondedness
that have been suggested by studies of captive titi monkeys. I
correlated
changes in these behavioral indicators with differences in the physical
environments (fruit abundance, territory location) and social
environment
(proximity of a sexual competitor to the subject's pairmate).
Both males and
females exhibited more affiliative and arousal behaviors
in the presence of real or simulated intruders
than in their absence. My thesis presented suggestive evidence that
male
investment
in the pair bond reflects a mixed reproductive strategy of direct mate
defense
via mate guarding and indirect mate defense via resource defense, and
female
investment reflects a similarly mixed strategy of resource defense and,
to a
lesser degree, mate defense. The multiple proposed pair bond functions
highlight the importance of considering both cooperative and
conflicting male
and female reproductive interests.
After
graduation, Jenna became a lecturer in Dept. of Ecology, Evolution &
Environmental Biology, Columbia University.
