PhD‐theses - Ethologische Gesellschaft

Research Update
THE INFLUENCE OF SOCIAL INTERACTION BETWEEN MALE CAVIES AND JUVENILE FEMALE CAVIES
(CAVIA APEREA) AND OF MALE ODORS ON THE MATURATION OF FEMALES
Antje Lembke
antje.lembke@gmx.de
Masters Thesis, supervised by Prof. Dr. Fritz Trillmich, Department of Animal Behavior, and Prof. Dr.
C. Müller, Dept. Chemical Ecology, University of Bielefeld
This study targeted the topic of male influence on the timing of female maturation. The
timing of female maturation is a crucial factor in the life history, especially of small, short
lived mammals. In mice the male influence is well known as the ‘Vandenberg effect’, elicited
by male urinary proteins. In the precocial caviomorph, Cavia aperea the male effect is not
elicited by metabolites in urine. The mechanism behind this effect is still unknown. I tested
the hypothesis that male behavior and male odor contribute to the acceleration of puberty
in females.
In the behavioral experiment, the female onset of fertility was examined. A pair of
females was housed either next to castrates or next to a male, separated by wire mesh. One
of the two females was put into contact with the male or castrate every four days for one
hour. During this time the behavior was recorded. Females housed next to males matured
significantly earlier than females housed next to castrates. The physical contact did not make
a difference in the onset of estrus in the females. Males and castrates did not differ in any of
the behaviors towards females recorded and no significant correlation was found in the
overall activity of males and castrates with the onset of estrus in the females.
To investigate olfactory stimuli, samples of perineal secretion were collected and
analyzed by gas‐chromatography and mass‐spectrometry (GCMS). The spectra of males and
castrates differed significantly. Various peaks were found in male perineal gland secretion
only, but no metabolites were found exclusively in castrates. The number of peaks found in
the male or castrate secretion was correlated with the onset of fertility of the corresponding
female in contact. The results of my experiments suggest that the difference in perineal
gland scent between fertile males and castrates could account for the difference in the
timing of puberty in female cavies. Further characterization of the active substances is
needed.
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