Submitted October 12, 2006
Returned for revision November 13, 2006
Accepted January 29, 2007
Male Reproductive Tract
Cycle Length of Spermatogenesis in Shrews (Mammalia:
Soricidae) with High and Low Metabolic Rates and Different
Mating Systems
Roumen Parapanov *,
Sébastien Nusslé ,
and
Peter Vogel
* To whom correspondence should be addressed. E-mail: roumen.parapanov{at}unil.ch.
Abstract
The aim of this study was to establish and compare the
duration of the seminiferous epithelium cycle of the
common shrew Sorex araneus, which is characterized
by a high metabolic rate and multiple paternity, and the
greater white-toothed shrew Crocidura russula,
which is characterized by a low metabolic rate and a
monogamous mating system. Twelve males of S.
araneus and fifteen males of C. russula were
injected intraperitoneally with 5-bromodeoxyuridine, and
the testes were collected. For cycle length determination,
we applied the classical method of estimation and linear
regression as a new method. With regard to the variance,
and even with a relatively small sample size, the new
method seems to be more precise. In addition, the
regression method allows the inference of information for
every animal tested, enabling comparison of different
factors with cycle length. Our results show that not only
increased testis size may lead to increased sperm
production, but also reduced the duration of
spermatogenesis. The calculated cycle length was 8.35 days
for S. araneus and 12.12 days for C.
russula. The data obtained in the present study
provide the basis for future investigations involving the
effects of metabolic rate and mating systems on the speed
of spermatogenesis.
Key words:
Male Reproductive Tract •
Testis •
Spermatogenesis
