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REPRODUCTION IN TWO SPECIES OF KANGAROO ( MACROPUS ROBUSTUS AND MEGALEIA RUFA IN THE ARID PILBARA REGION OF WESTERN AUSTRALIA
Author(s) -
SADLEIR R. M. F. S.
Publication year - 1965
Publication title -
proceedings of the zoological society of london
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.915
H-Index - 96
eISSN - 1469-7998
pISSN - 0370-2774
DOI - 10.1111/j.1469-7998.1965.tb02016.x
Subject(s) - biology , macropus , reproduction , fertility , fecundity , sperm , zoology , ecology , marsupial , demography , population , botany , sociology
The officiency of euro (Macropus robustus Gould) and marloo (Meguleia rufu Desmarest) reproduction was investigated on two pastoral leases, Mount Edgar and Mundabullangana, froni 1959 to 1961. Despite fluctuations in physical condition (due to seasonal changes in food availability and temperature), females of both species breod continuously and exhibit high lcvels of fertility and fecundity throughout tho year. The incidence of quioscent blast‐ ocysts has been documented in three populations of these kangaroos. A hypothesis is suggested that the ecological role of the quiescent blastocyst is to extend the sequence of parturitions under drought conditions. Three moasures of male fertility (test8is weight, density of sperm and total numbers of sperm in the ejaculato) showed no significant seasonal changes. Both species woro shown to have very much lower densities of sperm in the semen than any domestic eutherians. Female euros were aged by a dental index, and it was found that old females had a reduced fertility. The old malos of both species showed a reduced fertility. Continuous breeding and high reproductive efficiency in euros and marloos allows for a large recruitmcnt in these species. These phenomena seem to be related to the relatively long period of time between conception and weaning of tho young and the uncertainty of prediction of t'he optimal weaning season in an irregular desert environment.