Longitudinal monitoring of plasma and fecal androgens in the Tasmanian devil (Sarcophilus harrisii) and the spotted-tailed quoll (Dasyurus maculatus)

Improved knowledge of the breeding biology of carnivorous marsupials is warranted given their heightened conservation status. Past studies have focused on smaller dasyurids and little is known of male reproductive physiology in the larger species. This study aimed to characterize the pattern of androgen concentrations in male devils and spotted-tailed quolls and to evaluate fecal steroid measurement as a practical, alternative technique for monitoring reproductive activity. Blood and fecal samples were collected from captive adult devils (n=6) and adult quolls (n=8). Plasma and fecal androgen concentrations were significantly positively correlated. In both species there was a significant effect of season on androgen concentrations; and the annual increase preceded female estrus activity. For devils, fecal androgens were elevated during the austral summer: peak concentrations were observed in January-February, and copulation occurred from late February-late May. In quolls, fecal androgen concentrations were highest during austral autumn/winter: the annual increase began in April and copulation occurred from mid-May to early October. The lengthy period of elevated plasma and fecal androgens and protracted annual period of mating activity implies a period of extended spermatogenesis in both species.     

Extensive population decline in the Tasmanian devil predates European settlement and devil facial tumour disease

The Tasmanian devil (Sarcophilus harrisii) was widespread in Australia during the Late Pleistocene but is now endemic to the island of Tasmania. Low genetic diversity combined with the spread of devil facial tumour disease have raised concerns for the species’ long-term survival. Here, we investigate the origin of low genetic diversity by inferring the species'' demographic history using temporal sampling with summary statistics, full-likelihood and approximate Bayesian computation methods. Our results show extensive population declines across Tasmania correlating with environmental changes around the last glacial maximum and following unstable climate related to increased ‘El Niño–Southern Oscillation’ activity.     

Fecal steroid hormone analysis as an indicator of reproductive function in the cheetah

Techniques were developed and validated to measure fecal estrogen and progesterone concentrations of the female cheetah. Fecal samples were collected from seven mature females. Cheetahs were monitored before mating and continued until parturition. Four females had normal pregnancies, one conceived but the pregnancy resulted in spontaneous abortion, one was mated but apparently did not conceive and one was treated with gonadotropin-releasing hormone (GnRH) and human chorionic gonadotropin (hCG) to induce follicular growth and ovulation. Vaginal superficial cells increased with increasing estrogen concentrations. Peak estrogen occurred one day postcopulation. Increases in fecal progesterone concentrations, indicative of ovulation, occurred after copulation and hormonally induced ovulation. For the first time reproductive function can be monitored in the cheetah using noninvasive sample collection. © 1994 Wiley-Liss, Inc.     

Sexual swelling in mandrills (Mandrillus sphinx): a test of the reliable indicator hypothesis

Various hypotheses have been proposed to account for the functionof sexual swellings in female primates, but few empirical dataexist to test predictions arising from these hypotheses. Controversyhas recently arisen over a field study that appeared to supportthe predictions of the reliable indicator hypothesis. This hypothesisproposes that females compete for males or matings, that differencesin swelling size between females reliably advertise female quality,and that males use swelling characteristics to differentiallyallocate mating effort to females with certain swelling characteristics,hence to females of higher quality. To provide an independenttest of this hypothesis, we collected data concerning the sizeand coloration of 40 sexual swellings for 29 semi-free-rangingfemale mandrills, varying in age and parity, along with dataconcerning the behavior of males toward the females, and comparedthese with the long-term reproductive history of the females.We examined the following predictions: (1) swelling characteristicsare consistent across subsequent cycles for individual females,(2) swelling characteristics indicate aspects of female reproductivequality, and (3) males prefer to mate with females that showparticular swelling characteristics. Our results support prediction1; we found little change in swelling characteristics acrossswellings for individual females. However, we found no significantrelationships between female reproductive history and swellingcharacteristics and, thus, no support for prediction 2. Finally,we found only limited support for prediction 3; females withlarger (wider) sexual swellings were more likely to have a spermplug when maximally swollen. However, male mate-guarding wasnot significantly related to female swelling characteristics.Furthermore, in situations in which more than one female wasmaximally swollen, the alpha male (who has "free" choice) didnot show the most interest in the female with the largest swelling.We conclude that the reliable indicator hypothesis does notexplain variation in sexual swellings in female mandrills.     

Choline status is not a reliable indicator of moderate changes in dietary choline consumption in premenopausal women

For the prevention of liver dysfunction in women, a choline adequate intake of 425 mg/day was established. To date, the relationship between dietary choline intake and plasma concentrations of choline moieties remains relatively unexplored. As an extension of our previous work, this 14-week controlled feeding study investigated the relationship between moderate changes in dietary choline intake and blood indicators of status. The influences of folate intake and the methylenetetrahydrofolate reductase (MTHFR) C677T genotype were also considered. Healthy premenopausal women (n=45, 18-46 years) with the MTHFR 677CC (n=28) or TT (n=17) genotype consumed a folate-restricted diet for 2 weeks followed by randomization to one of four dietary treatments (n=6-9/group) differing in total choline (344-486 mg/day), betaine (122-349 mg/day) and/or folate (400-800 microg dietary folate equivalents/day) content for 12 weeks. Responses to treatment were assessed as changes in the plasma levels of choline moieties (i.e., betaine, choline, phosphatidylcholine and sphingomyelin) and/or leukocyte global DNA methylation between pretreatment (Week 2) and posttreatment (Week 14) values. No significant changes were detected in the measured variables in response to dietary increases in choline (i.e., 41% increase) or betaine (i.e., 286% increase) intake. However, the MTHFR C677T genotype, alone or together with a diet, influenced betaine (P=.03) and phosphatidylcholine (P=.03). These data suggest that choline status is not a reliable indicator of moderate changes in dietary choline intake possibly due to the engagement of compensatory mechanisms. In addition, the MTHFR C677T genotype appears to influence the direction and use of choline moieties in this group of women.     

Hormonal control of birth behavior in the Tasmanian devil Sarcophilus harrisii

In a number of marsupial species, females exhibit characteristic, stereotyped parturient behavior that facilitates the passage of the neonates to the pouch. In macropodids, this parturient behavior can be induced in non-pregnant females and males by treatment with either prostaglandin F2alpha (PGF2alpha) or oxytocin (OT). This study investigated the effects of PGF2alpha and OT on behavior of Tasmanian devils. Animals tended to sit or lie down quickly, with little vocalization, after treatment with PGF2alpha or OT, while after saline, the animals remained alert, seldom sat, and frequently vocalized. Hormone treatment caused increased respiration. Urogenital and pouch grooming, a characteristic element of parturient behavior in macropodids, was seen in only one devil after hormone treatment. However, no pouch or urogenital grooming was seen in videotape of a devil giving birth, so this may not be a feature of parturient behavior in this species. Overall behavior of males and females was very similar suggesting that the behavioral effects observed may be due to direct neural action of PGF2alpha or OT, rather than an indirect response to uterine or vaginal contractions caused by the hormones. This study is the first to demonstrate that OT results in PGF2alpha secretion as PGFM levels rose after OT injection.     

Genomics for conservation: a case study of behavioral genes in the Tasmanian devil

The increased availability of genomic resources for many species has expanded perspectives on problems in conservation by helping to design management strategies for threatened species. Tasmanian devils (Sarcophilus harrisii) are an iconic and endangered marsupial with an intensively managed breeding program aimed at preventing extinction in the wild caused by devil facial tumour disease. Between 2015 and 2017, 85 devils from this program were released to three sites in Tasmania to support wild populations. Of these, 26 were known to have been killed by vehicles shortly after release. A previous analysis indicated that increased generations in captivity was a positive predictor of vehicle strike, with possible behavioural change hypothesised. Here we use 39 resequenced devil genomes to characterise diversity at 35 behaviour-associated genes, which contained 826 single nucleotide polymorphisms (24 were non-synonymous). We tested for a predictor of survival by examining three genes (AVPR1B, OXT and SLC6A4) in 62 released devils with known fates (survived, N?=?39; died, N?=?23), and genome-wide associations via reduced-representation sequencing (1727 single nucleotide polymorphisms [SNPs]), in 55 devils with known fates (survived, N?=?38; died, N?=?17). Overall, there was little evidence of an association between genetic profile and probability of being struck by a vehicle. Despite previous evidence of low genetic diversity in devils, the 35 behaviour-associated genes contained variation that may influence their functions. Our dataset can be used for future research into devil behavioural ecology, and adds to the increasing body of research applying genomics to conservation problems.

     

Reproductive status and torpor of the marsupial Sminthopsis crassicaudata: Effect of photoperiod

1. 1. We investigated the effects of photoperiod on the reproductive state and the occurrence and pattern of torpor in male Sminthopsis crassicaudata.

2. 2. Testes regressed when animals were exposed to a short photoperiod (L:D 8:16) and recrudesced under a long photoperiod (L:D 16:8).

3. 3. Animals entered torpor under both photoperiods and no significant differences were observed in the frequency or physiological variables of torpor of S. crassicaudata between the short and long photoperiods.

4. 4. The differences in the response to photoperiod in thermal physiology and reproduction suggest that, unlike in many rodent species, torpor and reproduction in S. crassicaudata are controlled by separate environmental cues and mechanisms.

     

MHC gene copy number variation in Tasmanian devils: implications for the spread of a contagious cancer

Tasmanian devils face extinction owing to the emergence of a contagious cancer. Devil facial tumour disease (DFTD) is a clonal cancer spread owing to a lack of major histocompatibility complex (MHC) barriers in Tasmanian devil populations. We present a comprehensive screen of MHC diversity in devils and identify 25 MHC types and 53 novel sequences, but conclude that overall levels of MHC diversity at the sequence level are low. The majority of MHC Class I variation can be explained by allelic copy number variation with two to seven sequence variants identified per individual. MHC sequences are divided into two distinct groups based on sequence similarity. DFTD cells and most devils have sequences from both groups. Twenty per cent of individuals have a restricted MHC repertoire and contain only group I or only group II sequences. Counterintuitively, we postulate that the immune system of individuals with a restricted MHC repertoire may recognize foreign MHC antigens on the surface of the DFTD cell. The implication of these results for management of DFTD and this endangered species are discussed.     

Spatial ecology of the mulgara in arid Australia: impact of fire history on home range size and burrow use

Knowledge about the spatial ecology of small mammals in relation to fire history in arid zones in general and Australia in particular is limited. Here, we report data on the spatial ecology of the brush-tailed mulgara Dasycercus blythi in the hummock grasslands of Ulu r u – Kata Tju t a National Park during winter 2006, the beginning of the breeding season for this species. About 73% of the study area had been burnt in 2002 and spinifex cover was sparse. Mulgaras Marsupialia: Dasyuridae (six males and three females) were implanted with radio-transmitters and monitored daily for between 6 and 55 days. All mulgaras appeared to use defined home ranges, which overlapped extensively with those of several neighbours. Spatial overlap occurred between as well as within sexes. On average, males (25.5 ha) occupied significantly larger home ranges than females (10.8 ha). Mulgaras used a number of burrows within home ranges and several were used by more than one individual. Moreover, occasionally, two individuals used the same burrow simultaneously. Home ranges and burrows encompassed both mature spinifex Triodia basedowii and open regrowth areas and mulgaras did not exhibit a significant preference for either habitat type. However, three males were killed by introduced-predators and they all lived predominantly in the open regrowth area. We conclude that mulgaras do not select the dense cover of mature spinifex habitat, and might be subjected to increased risk from introduced predators, especially following fire.     

The impact of disease on the survival and population growth rate of the Tasmanian devil

1. We investigated the impact of a recently emerged disease, Devil Facial Tumour Disease (DFTD), on the survival and population growth rate of a population of Tasmanian devils, Sarcophilus harrisii, on the Freycinet Peninsula in eastern Tasmania. 2. Cormack-Jolly-Seber and multistate mark-recapture models were employed to investigate the impact of DFTD on age- and sex-specific apparent survival and transition rates. Disease impact on population growth rate was investigated using reverse-time mark-recapture models. 3. The arrival of DFTD triggered an immediate and steady decline in apparent survival rates of adults and subadults, the rate of which was predicted well by the increase in disease prevalence in the population over time. 4. Transitions from healthy to diseased state increased with disease prevalence suggesting that the force of infection in the population is increasing and that the epidemic is not subsiding. 5. The arrival of DFTD coincided with a marked, ongoing decline in the population growth rate of the previously stable population, which to date has not been offset by population compensatory responses.     

Cryopreservation of epididymal sperm collected postmortem in the Tasmanian devil (Sarcophilus harrisii)

Effective sperm cryopreservation protocols are limited to a small number of marsupial species. In this study, postmortem gamete rescue (PMGR) epididymal sperm samples from Tasmanian devils (N = 34) euthanized due to the fatal Devil Facial Tumor Disease were used to develop long-term sperm storage techniques for the species. Cryoprotectant toxicity associated with equilibration of sperm samples in a TEST yolk diluent (TEST; 189 mM N-Tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid, 85 mM Trizma base [Tris], 11 mM glucose, 20% vol/vol egg yolk; pH 7.1, and 315.0 ± 5.0 mOsm/kg) with a final concentration of 0.06 M trehalose, or 4%, 10%, and 18% vol/vol of either glycerol or dimethyl sulfoxide (DMSO), was examined over 12 h at 15 °C. Trehalose supplementation resulted in an immediate decline (P < 0.05) of total motility. After 12 h, total motility was reduced (P < 0.05) in treatments containing 18% glycerol, and 10% and 18% dimethyl sulfoxide. The effects of final glycerol concentration (4% and 10%), glycerol equilibration duration (10 min 1 h, or 3 h) prefreeze, freezing rate and the addition of 0.10 M lactose or a combination of 0.10 M lactose and 0.11 M raffinose were assessed during three experiments on the cryopreservation of postmortem gamete rescue samples in TEST. In all experiments, motility and viability were reduced (P < 0.01 postthaw). Samples cryopreserved in TEST supplemented with lactose or lactose with raffinose using a fast freezing rate (−8 °C/min from 4 to −40 °C, then −65 °C/min until −165 °C) produced the highest (P < 0.05) postthaw motility (18.6 ± 5.5% and 16.9 ± 8.5%, respectively), which represented 35% to 48% retention of prefreeze motility. These results apparently were the best postthaw results of dasyurid sperm reported to date and will help lay the foundations for developing assisted reproductive technologies for marsupial species.     

LXR stimulates a metabolic switch and reveals cholesterol homeostasis as a statin target in Tasmanian devil facial tumor disease

1. Download : Download high-res image (163KB)
2. Download : Download full-size image

     

Egg patterning is not a reliable indicator of intraspecific brood parasitism in the blue tit Cyanistes caeruleus

A recent study reported the incidence of intraspecific brood parasitism (IBP) in the blue tit, based on differences in pigmentation between eggs within clutches and the appearance of multiple eggs within a nest in a single day. Here we present data from another population of blue tits Cyanistes caeruleus in which we show that such evidence is not necessarily indicative of IBP. As in many other studies of birds, we found that the patterning and degree of pigmentation on eggs is individually highly characteristic of a female. As in the previous study of blue tits, a minority of clutches (about 3% of 904 clutches) contained one, two or three eggs that were distinctly different from the other eggs in the clutch, either in size or patterning, but not both. Molecular genetic analyses of parentage in a sample of these clutches with suspected IBP demonstrated unequivocally that all eggs within each clutch had in fact been laid by a single female, in all cases the social parent. We also found no evidence of IBP from paternity analyses of a sample of 3,529 offspring from 427 broods in this population, adding to previous evidence of the absence of IBP in this species. These findings cast doubt on the utility of purely observational approaches to provide evidence of intraspecific brood parasitism; our study suggests that egg morphology and records of laying patterns are inadequate to enable the identification of IBP.     

Evidence that disease-induced population decline changes genetic structure and alters dispersal patterns in the Tasmanian devil

Infectious disease has been shown to be a major cause of population declines in wild animals. However, there remains little empirical evidence on the genetic consequences of disease-mediated population declines, or how such perturbations might affect demographic processes such as dispersal. Devil facial tumour disease (DFTD) has resulted in the rapid decline of the Tasmanian devil, Sarcophilus harrisii, and threatens to cause extinction. Using 10 microsatellite DNA markers, we compared genetic diversity and structure before and after DFTD outbreaks in three Tasmanian devil populations to assess the genetic consequences of disease-induced population decline. We also used both genetic and demographic data to investigate dispersal patterns in Tasmanian devils along the east coast of Tasmania. We observed a significant increase in inbreeding (F_IS pre/post-disease −0.030/0.012, P<0.05; relatedness pre/post-disease 0.011/0.038, P=0.06) in devil populations after just 2–3 generations of disease arrival, but no detectable change in genetic diversity. Furthermore, although there was no subdivision apparent among pre-disease populations (θ=0.005, 95% confidence interval (CI) −0.003 to 0.017), we found significant genetic differentiation among populations post-disease (θ=0.020, 0.010–0.027), apparently driven by a combination of selection and altered dispersal patterns of females in disease-affected populations. We also show that dispersal is male-biased in devils and that dispersal distances follow a typical leptokurtic distribution. Our results show that disease can result in genetic and demographic changes in host populations over few generations and short time scales. Ongoing management of Tasmanian devils must now attempt to maintain genetic variability in this species through actions designed to reverse the detrimental effects of inbreeding and subdivision in disease-affected populations.     

Salivary IgA is not a reliable indicator of upper respiratory infection in collegiate female soccer athletes

It has been shown that mucosal immunity measures such as salivary immunoglobulin A (s-IgA) can be affected by sport activities and has resulted in an increased susceptibility to infection. However, there is limited research that has evaluated the change in s-IgA throughout a full sport training season. The purpose of the study was to evaluate the change in s-IgA levels and incidence of upper respiratory infection in the National Collegiate Athletic Association Division I level female soccer athletes compared to age matched controls over an entire sport training season. Saliva samples were collected from 12 randomly selected female collegiate soccer athletes and 8 age-matched controls. Samples were collected bimonthly from the athletes' pre-and post-sport training sessions and pre- and post-90-minute sedentary period for the controls. Analysis showed there was a significant (p < 0.05) group × time interaction in total protein (TP) for collections 1 and 4 and a significant (p < 0.05) group × time interaction in s-IgA/TP for collections 2 and 3. There was no significant difference (p > 0.05) between athletes and controls for s-IgA or total symptom days (TSDs). Furthermore, there was no significant correlation between absolute s-IgA and TSDs or s-IgA/TP and TSDs throughout the sport training season. The large range of measurable levels for s-IgA at the different time points for athletes and controls and the lack of relationship between s-IgA levels and TSDs indicate that s-IgA is not an appropriate measure to determine an athlete's susceptibility to during a training season.     

Ascorbic acid status in high-mountain charr,Salvelinus alpinus,in relation to the reproductive cycle

Synopsis Concentrations of total and dehydroascorbic acids and of glutathione were determined in tissues of male and female Arctic charr at different stages of the reproductive cycle. In fish inhabiting an Alpine lake (2344 m above sea level) the ascorbic acid concentrations were significantly higher in the ovary (344 g g^–1 in August) than in the testis (62.6 g g^–1). The ascorbate concentration was significantly higher in liver and kidney of males than in females in the period prior to spawning. This suggests that there was an intensive investment of body ascorbate reserves in the ovary and the results indicated that females deposited approximately 10 times the amount of vitamin C in ovaries than males deposited in testes. However, the endogenous stores cannot account for all ascorbate deposited in ovaries and the remainder must come from food consumed in summer. Since the resident charr of the high-mountain lake had the ascorbate concentration in ovary by one order of magnitude higher than in cultured salmonids it is plausible to speculate that the change in ascorbic acid metabolism reflects the adaptation to the harsh environmental conditions.