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Most mammals exhibit seasonal variation in the reproductive capacity of one or both sexes. While the female southern hairy-nosed wombat Lasiorhinus latifrons is a known seasonal breeder, the extent of seasonality in the male has not been documented. To examine this, gross body measurements including scrotal diameter and the dimensions of the accessory gland bulge were recorded and male reproductive tracts were examined between 1993 and 2000. Testes, epididymides and accessory glands from all males were dissected free of connective tissue and weighed. In addition, matched semen samples were collected over four time points in 2000 corresponding to the breeding season (September), immediately post-breeding season (November), during the non-breeding season (January), and immediately before the onset of the next breeding season (June) as determined from female reproductive status. Semen was collected by electro-ejaculation and analysed for volume, sperm number and motility characteristics. Ejaculate volume, total ejaculate sperm number, percentage motile sperm, and the sperm motility rating and index were all significantly elevated in September and significantly lower in November and January. This correlated with a significant increase in body weight, peri-cloacal gland width, and the weights of the prostate, Cowper's glands, urethral bulb and crus penis. The data confirm that male reproduction in the southern hairy-nosed wombat, like that of the female, is highly seasonal with a peak in reproductive capacity occurring in August–September and a reduction by November.
This study investigated burrow use and ranging behaviour in the southern hairy-nosed wombat Lasiorhinus latifrons in semi-arid South Australia. Sixteen adult wombats were fitted with radio transmitters and monitored monthly from July 2001 to February 2002. Wombats generally used between one and five warrens, preferred large warrens with a greater number of entrances and showed a preference for one or two warrens. Across the study period there was no apparent change in burrows used within warrens. Radio-tracking indicated that animals spent very little time above ground (26% of 1115 night-time fixes), centred their activity around their preferred warrens, and moved, on average, 99 m/h and 221 m/night. Mean home-range size, estimated using minimum convex polygons and the harmonic mean method from location data, obtained through triangulation, and daytime warren fixes, ranged from 1.3 to 4.8 ha. Home-range size was similar between males and females and home ranges overlapped substantially. The data highlight the importance of burrows to southern hairy-nosed wombats in shaping their home ranges. It seems likely that the use of burrows and a specialized diet are important energy saving strategies for this species in such unpredictable regions of South Australia.
Using a porthole camera the architecture of the warrens of the southern hairy-nosed wombat Lasiorhinus latifrons was examined at two sites in southern Australia. The complexity of warrens varied from simple, single-entrance warrens to a system 89 m long with 28 entrances. Logging of deep tunnel temperatures showed daily ranges of < 1 °C over periods in which surface temperatures ranged up to 24 °C, but mean tunnel temperatures varied 15.9 °C between winter and summer. Humidity gradients were maintained between the tunnel and the surface and depended on the length and depth of the tunnel. Oxygen and carbon dioxide levels were similar to those in free atmospheric air in unoccupied tunnels, but in occupied tunnels reached 16.3% and 3%, respectively. There is no specific orientation of tunnel entrances or defined mound shape. Wombat warrens ameliorate surface conditions in habitats of low humidity and high temperatures while humidity advantages promote the construction of warrens beyond the requirements for temperature modulation.
The mouse-like marsupial Antechinus agilis is common to south-eastern Australia with breeding and life-history traits being highly synchronous. Mating activity is confined to a 10- to 15-day period in August, at the end of which all males die as a result of a stress-induced suppression of the immune system. Ovulation occurs at this time and females rely on stored sperm from specialized crypts in the lower isthmus of the oviduct for successful fertilization. Here we report a high incidence of mixed paternity litters, which can be attributed to sperm from multiple males being stored in the isthmic crypts. Data from this study also suggest a possible second male siring advantage in controlled ex situ sperm competition mating trials, irrespective of the delay between the two males being given mating access to the female or of the mating time relative to ovulation. In determining paternity through DNA profiling, population genetic data were obtained that showed significant differences in the genetic heterozygosity between unrelated adults, half siblings and full siblings. We suggest that the isthmic crypts, in addition to storing viable sperm, are capable of releasing a mix of sperm that increases the likelihood of mixed paternity litters. This allows all mating males the opportunity to sire young, increases female reproductive fitness and overall maintains high levels of population genetic heterozygosity in the face of total male mortality annually.
The prevalence of abnormal serum total thyroxine (T4) and triiodothyronine (T3) concentrations were determined in 1,206 in-patients in two associated psychiatric hospitals. The biochemical pattern of primary hypothyroidism occurred in five females and one male (prevalence 0.5 per cent), but in only one patient was the diagnosis clinically obvious. Eight patients (all female) were clinically hyperthyroid (prevalence 0.7 per cent), of whom six were previously undiagnosed. There was no evidence that phenothiazines or benzodiazepine therapy had any significant effect on thyroid hormone levels. The small differences in thyroid hormone levels between psychiatric diagnostic groups could be explained by differences in age distribution.
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