Artificial Insemination In The Koala : Its Role In Conservation Biology And Impact On Current Wildlife Legislation
P. O'Callaghan' & S.D. Johnston
1Lone Pine Koala Sanctuary, Jesmond Road, Fig Tree Pocket, 4069
2School of Veterinary Science, The University of Queensland, 4072.
Assisted breeding technology offers new and exciting possibilities to traditional methods of ex situ management and breeding of captive mammals. Although these techniques are increasingly being used successfully in the captive propagation of eutherian wildlife, production of marsupial pouch young by means of artificial insemination, has only recently been achieved.
In May of this year, the University of Queensland and Lone Pine Koala Sanctuary jointly announced the birth of the world's first Koala to be born by means of hormonal induction of ovulation and artificial insemination (Al). This work represents the culmination of five years of systematic investigation into three key areas of Koala reproductive research; (1) semen collection (Wildt et al., 1991; Johnston et al., 1994; 1997a) and preservation (Johnston et a!, 1992; 1993), (2) studies to determine the timing of insemination (Johnston et al., 1997b) and (3) examination of female reproductive anatomy to determine the most appropriate site for the deposition of the inseminate.
A recent review of the status of the Koala in Australia (ANZECC, 1998) revealed that while the species was under no immediate threat of extinction on a national basis, regional conservation status varied significantly; being secure in some areas to vulnerable or extinct in others. For example, in Queensland, population numbers are slowly declining and in New South Wales, Koalas have disappeared from 50-75% of their range. At the other extreme, some Koala populations in Victoria and South Australia occur in such large densities that they are causing significant defoliation of eucalypt species, prompting recommendations to actually cull animals (Possingham et aL, 1996).
Koalas also appear to have little trouble breeding both in the wild and in captivity. Martin and Handasyde (1990) have reported that the intrinsic rate of increase of a wild disease free, Victorian Koala populations can reach as high as 0.26, noting that this was approximately equivalent to a doubling of the population every three years. Lone Pine Koala Sanctuary presently holds approximately one hundred and thirty Koalas, the majority of which have been born in the sanctuary. A controlled selective breeding program managed to maintain maximum genetic diversity of the captive population results in the production of approximately 30 pouch young each breeding season (O'Callaghan, 1996). Given that the Koala is currently not threatened with extinction and that it appears to have little problem reproducing either in the wild or captivity, there appears to be no advantage in trying to improve reproductive output via assisted reproduction. Why then bother developing artificial breeding technology in this species? What is the value of artificial insemination to Koala conservation biology?