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Abstract

Rattus rattoides is a pest widely spreading over south-eastern China. In
Fujian Province it destroys one fifth of the crops (rice, wheat, sweat potato, peanut,
sugar cane, banana and other vegetables) in the field every year. A good range of
pesticides have been applied to minimize the pest's damage, yet its biology is hardly
studied. This preliminary study is to investigate some aspects of reproductive
biology and the roles of olfactory cues in the reproduction of this rodent.
All the experiments were carried out in Fujian, P. R. China during June 1990
to June 1991. The results of the investigations suggest that this species has the
potential to be tamed as an experimental laboratory species and olfactory cues from
an adult male or female play important roles in the growth and sexual development
of young of the two sexes.
1. The average and the maximum body weights were examined. The growth
rate of male and female rats before and after weaning were observed. No obvious
difference has been found in body size and weight between sexes in adults of this
species. The reproductive ability of the females in laboratory was found similar in
different months with two low breeding rates in February and August.
2. The sexual maturation of the males developed in three stages: (a), the
elevation of testosterone titre in blood; (b ), the growth of the body and testes
reached a plateau and mature sperm had been transported into the convoluted ducts;
(c), the cessation of the growth of epididymes and the success of reproduction.
3. The timing of the onset of puberty (vaginal opening) of females was found
to be variable when measured in different seasons, but the body weights at the time
of attaining puberty were similar. The onset of puberty of the females was
accelerated by cohabiting with adult males or by the olfactory cues from adult
males, and was delayed in the presence of olfactory cues from adult females.
4. Mean lengths of oestrous cycles of the adult females in different seasons
were not significantly different from each other. Olfactory cues from adult males or
housing under group conditions did not alter the lengths of the females' oestrous
cycles.
5. Group-living significantly retarded the growth and sexual development of
young males. Olfactory cues from adult males greatly promoted the growth and
development of testes in young conspecifics.

Item Type:	Thesis - PhD
Authors/Creators:	Xu, Zhongjian
Keywords:	Rattus, Rattus
Copyright Holders:	The Author
Copyright Information:	Copyright 1994 the Author - The University is continuing to endeavour to trace the copyright owner(s) and in the meantime this item has been reproduced here in good faith. We would be pleased to hear from the copyright owner(s).
Additional Information:	Includes bibliographical references (leaves 152-186). Thesis (Ph.D.)--University of Tasmania, 1994
Item Statistics:	View statistics for this item

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