School of Animal Biology M092, The University of Western Australia, Perth, WA 6009, Australia.
Gen Comp Endocrinol. 2012 Sep 1;178(2):347-54. doi: 10.1016/j.ygcen.2012.06.013. Epub 2012 Jun 27.
Details of the reproductive endocrinology of the dibbler, Parantechinus apicalis, an endangered member of the Family Dasyuridae, are presented from two geographically-separated populations, living either on the mainland or on islands in Jurien Bay, Western Australia. Plasma free cortisol in males measured in the island population during 1998/9 did not differ between the breeding and non-breeding season, but during the March rut in 2000, when males died after breeding, free cortisol levels were significantly raised. Post-mating mortality in dibbler males is facultative, rather than obligatory and the cortisol data implicate the same physiological sequelae described in other dasyurids. In females, a single annual oestrus was recorded during late summer to autumn in both populations with an onset earlier by 12 days in the mainland animals. Faecal steroids excreted as progesterone metabolites (PM) and oestradiol-17β were measured during the annual oestrous period and showed significantly higher PM concentrations in island animals. Oestradiol, although raised, was not different between the two populations. A profile of PM levels throughout gestation revealed a small peak at the time of ovulation, followed by slowly rising levels to peak 8 days before birth, indicating slow development of the corpora lutea. Using collective data, the presumptive day of ovulation could be identified, allowing the calculation of a presumptive gestation length of 45days in dibblers from mainland populations. This gestation length compares with that of a related species, Pseudantechinus macdonnellensis, reported at 45-55 days. A surprising finding is the significantly shorter gestation period of approximately 38 days in island animals compared with those from the mainland. This and other differences between reproductive parameters of island and mainland populations are discussed in the context of the 'island syndrome'.
来自澳大利亚杰里汶湾两个地理位置分离的种群（一个在大陆，另一个在岛屿上）的袋狸（袋狸科的一员，濒危物种）的生殖内分泌学的详细信息被呈现出来。2000 年 3 月繁殖季节结束后，雄性袋狸死亡，雄性袋狸的皮质醇水平显著升高。在 1998/9 年，岛上种群在繁殖季节和非繁殖季节之间，其血浆游离皮质醇没有差异，但在 2000 年 3 月繁殖期的发情期，雄性袋狸死亡，皮质醇水平显著升高。袋狸雄性的交配后死亡率是有条件的，而不是强制性的，皮质醇数据暗示了在其他袋鼬科动物中描述的相同生理后果。在雌性中，两个种群在夏末至秋季都记录到一个单一的年度发情期，而在大陆动物中，发情期提前了 12 天。在年度发情期期间，作为孕酮代谢物（PM）和雌二醇-17β 的粪便类固醇被测量，结果显示岛屿动物的 PM 浓度显著升高。尽管雌二醇升高，但两个种群之间没有差异。整个妊娠期 PM 水平的变化曲线显示，在排卵时出现一个小高峰，然后缓慢上升，在分娩前 8 天达到峰值，表明黄体的发育缓慢。使用汇总数据，可以确定排卵的推定日期，从而计算出来自大陆种群的袋狸的推定妊娠期为 45 天。这个妊娠期与相关物种 Pseudantechinus macdonnellensis 的 45-55 天报道的妊娠期相比，相对较短。一个令人惊讶的发现是，与来自大陆的袋狸相比，岛屿袋狸的妊娠期明显短约 38 天。与大陆种群相比，岛屿种群的生殖参数存在显著差异，这在“岛屿综合征”的背景下进行了讨论。
