Letteratura scientifica selezionata sul tema "Antechinus flavipes Reproduction"

Animals may be released into the wild for introduction, translocation or rehabilitation programs. Often, released animals do not survive or reproduce as well as wild conspecifics. Another circumstance whereby animals may be released is the return to the wild of research subjects, and although these animals may be expected to fare better than those from introduction, translocation or rehabilitation programs, there is little information regarding their subsequent survival and reproduction. We examine here the survivorship and reproductive success of five (one male, four female) yellow-footed antechinus (Antechinus flavipes) released back into the wild after being held in captivity for approximately one week for physiological experiments. Three of the four female Antechinus were recaptured after release and, on inspection, all three had 10 pouch young. Survivorship after release of antechinus held in captivity (0.75) was not different from the population as a whole, which ranged between 0.5 and 1.0. We therefore present unequivocal evidence that Antechinus released into the wild after physiological experiments can successfully survive and reproduce. This information is important for wildlife managers and animal ethics committees when considering the fate of ex-research animals.

The population and reproductive ecologies of three sympatric species of antechinus were examined in upland rainforests in the wet tropics of Queensland. The three species, Antechinus stuartii adustus, A. flavipes rubeculus and A. godmani, exhibited unusually low trapping success compared with that of sites in temperate regions of Australia. Spatial distributions were extremely patchy both between and within study sites. Comparison with trapping data for temperate populations of A. stuartii and A. flavipes suggests that densities in the wet tropics are among the lowest in Australia. The reproductive season was similar for the three species, commencing during the mid-dry season with juveniles weaned by the early to mid-wet season. The phenomenon of male die-off was observed in the three species. However, the highly synchronous two- week breeding season observed in temperate populations of A. stuartii and A. flavipes was not observed in the tropical populations. The breeding season of the tropical species extended over a six- week period. Timing of reproduction in A. s. adustus and A. f. rubeculus was more similar to temperate than to subtropical populations of A. s. stuartii and A. f. flavipes.

This paper uses a combined morphological, molecular and ecological approach to assess the taxonomic status of Antechinus flavipes leucogaster from Western Australia, and its relationship to A. flavipes flavipes from eastern Australia. Morphological analyses show that A. flavipes leucogaster is smaller and finer than its eastern Australian counterpart in both cranial and dental dimensions. Phylogenetic analyses of partial cytochrome-b sequences showed that A. flavipes flavipes and A. flavipes leucogaster form reciprocally monophyletic clades that have a relatively high level of divergence (approximately 6%). Analysis of the timing of reproduction indicates that the two subspecies show opposite responses to latitude, with A. flavipes leucogaster ovulating later at high latitudes and A. flavipes flavipes ovulating later in more northerly parts of its range. The combined data and the entirely allopatric distributions of the two subspecies confirm their distinctive status. Bioclimatic analysis suggests further that A. flavipes leucogaster occupies wetter but seasonally more variable environments than its eastern relative. It is clear from the level of morphological, molecular, reproductive and distributional differences that A. flavipes flavipes and A.�flavipes leucogaster should be regarded as separate taxa for the purposes of conservation management, and their current subspecific status should be maintained.

Males of the genus Antechinus (Dasyuromorphia) undergo dramatic behavioural, physical and physiological change that results in complete male mortality after the mating period. Occasionally, males in the wild survive longer than this immediate post-mating period, and post ‘die-off’ survivorship for a second year has also been documented in captivity. The present study sought to quantify changes in the physiology and behaviour of male A. flavipes and A. stuartii that survive through a second year of life. Males from both species never demonstrated spermatorrhoea in their second year, although secondary sexual characteristics and sexual behaviour were recovered in their second year. Thus, the seminiferous tubular collapse seen before the mating period in their first year of life is irreversible and complete, although the cycling of other sexual characteristics suggests that the hypothalamic-pituitary-gonadal pathways and function of the interstitial cells of the testes are retrievable.

Abstract In a changing climate, southern hemisphere mammals are predicted to face rising temperatures and aridity, resulting in food and water shortages, which may further challenge already constrained energetic demands. Especially semelparous mammals may be threatened because survival of the entire population depends on the success of a single breeding event. One of these species, the yellow-footed antechinus, Antechinus flavipes, a small, heterothermic marsupial mammal, commences reproduction during winter, when insect prey is limited and energetic constraints are high. We examined the inter-relations between thermal and foraging biology of free-ranging A. flavipes and examined whether they use torpor for energy conservation, despite the fact that reproduction and torpor are considered to be incompatible for many mammals. Females used torpor during the reproductive season, but patterns changed with reproductive status. Prior to breeding, females used frequent (86% of days), deep and long torpor that was more pronounced than any other reproductive group, including pre-mating males (64% of days). Pregnant females continued to use torpor, albeit torpor was less frequent (28% of days) and significantly shorter and shallower than before breeding. Parturient and lactating females did not express torpor. During the mating period, males reduced torpor use (24% of days). Pre-reproductive females and pre-mating males were the least active and may use torpor to minimize predator exposure and enhance fat deposition in anticipation of the energetic demands associated with impending mating, gestation and lactation. Reproductive females were most active and likely foraged and fed to promote growth and development of young. Our data show that A. flavipes are balancing energetic demands during the reproductive season by modifying torpor and activity patterns. As the timing of reproduction is fixed for this genus, it is probable that climate change will render these behavioural and physiological adaptations as inadequate and threaten this and other semelparous species.