Establishment of a captive colony of Bettongia tropica (Marsupialia: Potoroidae) by cross‐fostering; and observations on reproduction

Abstract

It is demonstrated that cross-fostering is a practical way of improving the rate of increase of a rare species in captivity. Two adult Bettongia tropica were captured in northern Queensland and housed in captivity in Adelaide, South Australia. Eleven pouch young born in captivity to the wild-caught B. tropica were transferred at 20 days old or older to B. penicillata foster mothers and nine were reared successfully. Of a further 10 young not fostered, six were reared by the wild-caught mother. Fostering allowed the wildcaught female to produce surviving young nearly twice as frequently as if she had reared them in her pouch.Sexual maturity occurred at 246±523 days (x Å = 407.2 59.9 days) in 4 males and at 185±429 days (x Å = 300.5 26.0 days) in 11 females. Breeding continues throughout the year and females undergo embryonic diapause whilst supporting a pouch young. The female reproductive system is remarkable for its relatively long urethra and lateral vaginae and consequently short urogenital sinus. The male reproductive system is unremarkable, having a carrot-shaped prostate gland and three pairs of Cowper's glands, as do many other macropodoid species. Two pairs of paracloacal glands are found in males and females.

Embryonic diapause: development on hold

“…However, the precise mechanisms by which the uterus exerts its influence on the embryo are still not clearly understood. (Selwood, 1980, Renfree, 1981, Gilbert, 1984, Nelson and Goldstone, 1986, Hodara et al, 1989, Sandell, 1990, Huang et al, 1993, Atkinson, 1997, Newkirk et al, 1997, Smith, 1998, Fisher, 1999, Johnson and Delean, 1999, Crocker et al, 2001, Johnson and Delean, 2002, Courtenay and Friend, 2004, Thom et al, 2004, Delean, 2007, Knott et al, 2013 an increased understanding of the embryo-uterine dialogue has implications not only for women with recurrent miscarriages but also in improving the success rate of embryo transfers resulting from assisted reproductive technologies.…”

Artificial insemination in marsupials

“…It has been applied to enhance the reproductive rate and productivity of young of threatened species from the marsupial families Macropodidae and Potoroidae [23,[80][81][82][83][84]. This approach makes use of the long established principle that small pouch young, as early as day 1 of pouch life, can be transferred to the pouch of an appropriately prepared surrogate mother where normal development to pouch emergence occurs [15,83,85].…”

“…There are questions over the subsequent social training and behaviour of these animals, but evidence to date is that these animals do not show gross behavioural abnormalities, but readily recognize and mate with their own species provided once weaned, they are housed with their own kind [23,80,83,85]. Cross fostering can potentially increase the production of young of the threatened species by 2-8-fold [23,80,83]. This unique form of surrogacy allows harvesting of young animals from captive or free ranging populations, the mother's of which would subsequently return to estrus and breed again.…”

Survival of very small macropod pouch young followingshort‐term isolation from the pouch at various environmental temperatures

“…Recently pouch young removal and cross-fostering have been used to accelerate rapidly the production of young (up to sixfold) in colonies of the endangered brush-tailed rock wallaby, Petrogale penicillata (Taggart et al, 2002), and northern bettong, Bettongia tropica (Smith, 1998). Cross-fostering refers to the rearing of young by foster mothers of a different species.…”

“…Cross-fostering refers to the rearing of young by foster mothers of a different species. In terms of marsupial conservation, the aim of this procedure is to curtail the period of lactational anoestrous or lactational quiescence from the mother's reproductive cycle, allowing her to undergo a series of pregnancies with a minimum of intervening lactation and thereby enhancing her reproductive rate (Merchant & Sharman, 1966;Smith, 1998;Taggart et al, 2002). Without the addition of new genetic stock, however, the use of crossfostering techniques can rapidly lead to an over-representation of a particular individual's genes within a captive population.…”