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Lunn TJ, Nicol SC, Buettel JC, Brook BW. Population demography of the Tasmanian short-beaked echidna (Tachyglossus aculeatus). AUST J ZOOL 2022. [DOI: 10.1071/zo21037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Abstract
Abstract
Tachyglossus aculeatus (Shaw, 1792) is a monotreme commonly called the short-beaked echidna. Although considered Australia’s most common native mammal because of its continent-wide distribution, its population numbers everywhere are low. It is easily distinguished from all other native Australian mammals because of its spine-covered body, hairless beak, and unique “rolling” gait. The five subspecies, one of which is found in Papua New Guinea, show variations in fur density, spine diameter, length, and number of grooming claws. The Kangaroo Island short-beaked echidna Tachyglossus aculeatus multiaculeatus is listed as “Endangered” but all other Tachyglossus are listed as “Least Concern” in the 2016 International Union for Conservation of Nature and Natural Resources Red List.
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Affiliation(s)
- Peggy D Rismiller
- Pelican Lagoon Research & Wildlife Centre, Penneshaw, South Australia, Australia
- School of Biological Sciences, The University of Adelaide, Adelaide, South Australia, Australia
| | - Frank Grutzner
- The Environment Institute, The University of Adelaide, Adelaide, South Australia, Australia
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Nicol SC, Andersen NA, Morrow GE, Harris RL. Spurs, sexual dimorphism and reproductive maturity in Tasmanian echidnas (Tachyglossus aculeatus setosus). AUSTRALIAN MAMMALOGY 2019. [DOI: 10.1071/am18005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
We present data from an 18-year study of a wild population of Tasmanian echidnas, which show that the presence of spurs in an adult are a reliable indicator of sex, and that there is a slight but significant sexual dimorphism in size, with a male to female mass ratio of 1.1. Minimum age at first breeding in the wild for Tasmanian echidnas was 5 years, as has been found on Kangaroo Island, compared with 3 years in captive echidnas. It is often assumed that although the echidna is distributed throughout Australia, New Guinea and off-shore islands that all aspects of its basic biology are the same in all populations, but comparisons of our results with data from other populations suggest that there may be differences in size and sexual dimorphism.
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Abstract
In 1803, the French anatomist Étienne Geoffroy Saint-Hilaire decided that the newly described echidna and platypus should be placed in a separate order, the monotremes, intermediate between reptiles and mammals. The first physiological observations showed monotremes had low body temperatures and metabolic rates, and the consensus was that they were at a stage of physiological development intermediate between "higher mammals" and "lower vertebrates." Subsequent studies demonstrated that platypuses and echidnas are capable of close thermoregulation in the cold although less so under hot conditions. Because the short-beaked echidna Tachyglossus aculeatus, may show very large daily variations in body temperature, as well as seasonal hibernation, it has been suggested that it may provide a useful model of protoendotherm physiology. Such analysis is complicated by the very significant differences in thermal relations between echidnas from different climates. In all areas female echidnas regulate Tb within 1°C during egg incubation. The lactation period is considered to be the most energetically expensive time for most female mammals but lactating echidnas showed no measurable difference in field metabolic rate from non-lactating females, while the lactation period is more than 200 days for Kangaroo Island echidnas but only 150 days in Tasmania. In areas with mild winters echidnas show reduced activity and shallow torpor in autumn and early winter, but in areas with cold winters echidnas enter true hibernation with Tb falling as low as 4.5°C. Monotremes do not possess brown adipose tissue and maximum rates of rewarming from hibernation in echidnas were only half those of marmots of the same mass. Although echidnas show very large seasonal variations in fat stores associated with hibernation there is no relationship between plasma leptin and adiposity. Leptin levels are lowest during post-reproductive fattening, supporting suggestions that in evolutionary terms the anorectic effects of leptin preceded the adiposity signal. BMR of platypuses is twice that of echidnas although maximum metabolism is similar. High levels of thyroid hormones in platypuses may be driving metabolism limited by low body temperature. Monotremes show a mosaic of plesiomorphic and derived features but can still inform our understanding of the evolution of endothermy.
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Affiliation(s)
- Stewart C. Nicol
- Biological Sciences, University of TasmaniaHobart, TAS, Australia
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Morrow GE, Jones SM, Nicol SC. Interaction of hibernation and male reproductive function in wild Tasmanian echidnasTachyglossus aculeatus setosus. J Mammal 2016. [DOI: 10.1093/jmammal/gyw013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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Russell F, Burke D. Conditional same/different concept learning in the short-beaked echidna (Tachyglossus aculeatus). J Exp Anal Behav 2016; 105:133-54. [DOI: 10.1002/jeab.185] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 11/29/2015] [Indexed: 11/09/2022]
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Wallage A, Clarke L, Thomas L, Pyne M, Beard L, Ferguson A, Lisle A, Johnston S. Advances in the captive breeding and reproductive biology of the short-beaked echidna (Tachyglossus aculeatus). AUST J ZOOL 2015. [DOI: 10.1071/zo14069] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Captive breeding of the short-beaked echidna (Tachyglossus aculeatus) has proven a difficult challenge; as recently as 2009, there were fewer than 10 echidnas born in captivity. We present observations of captive reproductive behaviour following video surveillance and measurements of body temperature collected from six captive female echidnas over a six-year period. In the first series of observations (2009–10) we examined the efficacy of artificial burrow boxes as possible aids for reproductive success. Females with access to burrow boxes had significantly higher levels of reproductive activity (P = 0.001), there was coincidental improvement in the production of eggs or pouch young (two eggs, one unhatched and one offspring). During 2009–10, a range of reproductive behaviours (courtship, copulation and postcopulation) were documented and analysed, as were new observations of oestrous cycle activity. Female body temperature was characteristically stable during egg incubation during this study and has the potential to be used as a tool for the assessment of reproductive status. Following initial observations, burrow boxes and infrared lamps were implemented as standard husbandry in our echidna breeding facility and the effects on reproductive success were monitored, albeit less intensively, for a further four years (2011–14). Although no direct causal effect could be ascribed, the use of burrow boxes and heat lamps coincided with a total of 13 young being born to four females in the last four years (2011–14). These female echidnas were found to be receptive at intervals throughout the breeding season, both before and after presumed incubation phases, suggesting that captive animals exhibit polyoestry. In 2012 and 2014, the same female showed evidence of producing two young from one breeding event.
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White CR, Kearney MR. Metabolic scaling in animals: methods, empirical results, and theoretical explanations. Compr Physiol 2014; 4:231-56. [PMID: 24692144 DOI: 10.1002/cphy.c110049] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Life on earth spans a size range of around 21 orders of magnitude across species and can span a range of more than 6 orders of magnitude within species of animal. The effect of size on physiology is, therefore, enormous and is typically expressed by how physiological phenomena scale with mass(b). When b ≠ 1 a trait does not vary in direct proportion to mass and is said to scale allometrically. The study of allometric scaling goes back to at least the time of Galileo Galilei, and published scaling relationships are now available for hundreds of traits. Here, the methods of scaling analysis are reviewed, using examples for a range of traits with an emphasis on those related to metabolism in animals. Where necessary, new relationships have been generated from published data using modern phylogenetically informed techniques. During recent decades one of the most controversial scaling relationships has been that between metabolic rate and body mass and a number of explanations have been proposed for the scaling of this trait. Examples of these mechanistic explanations for metabolic scaling are reviewed, and suggestions made for comparing between them. Finally, the conceptual links between metabolic scaling and ecological patterns are examined, emphasizing the distinction between (1) the hypothesis that size- and temperature-dependent variation among species and individuals in metabolic rate influences ecological processes at levels of organization from individuals to the biosphere and (2) mechanistic explanations for metabolic rate that may explain the size- and temperature-dependence of this trait.
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Affiliation(s)
- Craig R White
- School of Biological Sciences, The University of Queensland, St Lucia, Queensland, Australia
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Morrow GE, Nicol SC. Maternal care in the Tasmanian echidna (Tachyglossus aculeatus setosus). AUST J ZOOL 2012. [DOI: 10.1071/zo12066] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Parental care is central to the differences in reproductive behaviour and energy expenditure between males and females, and it is therefore crucial for understanding animal mating systems. We investigated post-gestation maternal care in a wild population of short-beaked echidnas (Tachyglossus aculeatus) in the Tasmanian midlands using a combination of external temperature loggers and motion-triggered infrared cameras. For the first few weeks of early lactation mothers do not leave their nursery burrow, which they keep at a stable and warm temperature, resulting in a greater rate of maternal mass loss during the period of maternal burrow confinement than during hibernation. However, after lactating mothers recommence feeding, they raise a young to ~1.5 kg on a diet of their milk while increasing their own body mass by a similar amount. Weaning in our population appears not to be abrupt as there is a period where young echidnas begin exploratory foraging while their mother is still lactating. After young are weaned and abandon the nursery burrow, there appear to be no further associations between mothers and young despite young echidnas remaining within their mother’s home range for the first 12 months of their life. Female echidnas time reproductive events with increases in ecosystem productivity, so that young are weaned at a time of maximum food abundance.
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Nicol SC, Vanpé C, Sprent J, Morrow G, Andersen NA. Spatial ecology of a ubiquitous Australian anteater, the short-beaked echidna (Tachyglossus aculeatus). J Mammal 2011. [DOI: 10.1644/09-mamm-a-398.1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Morrow G, Nicol SC. Cool sex? Hibernation and reproduction overlap in the echidna. PLoS One 2009; 4:e6070. [PMID: 19562080 PMCID: PMC2699653 DOI: 10.1371/journal.pone.0006070] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2009] [Accepted: 06/02/2009] [Indexed: 11/18/2022] Open
Abstract
During hibernation there is a slowing of all metabolic processes, and thus it is normally considered to be incompatible with reproduction. In Tasmania the egg-laying mammal, the echidna (Tachyglossus aculeatus) hibernates for several months before mating in mid-winter, and in previous studies we observed males with females that were still hibernating. We monitored the reproductive activity of radio-tracked echidnas by swabbing the reproductive tract for sperm while external temperature loggers provided information on the timing of hibernation. Additional information was provided by camera traps and ultrasound imaging. More than a third of the females found in mating groups were torpid, and the majority of these had mated. Some females re-entered deep torpor for extended periods after mating. Ultrasound examination showed a developing egg in the uterus of a female that had repeatedly re-entered torpor. The presence of fresh sperm in cloacal swabs taken from this female on three occasions after her presumed date of fertilization indicated she mated several times after being fertilized. The mating of males with torpid females is the result of extreme competition between promiscuous males, while re-entry into hibernation by pregnant females could improve the possibility of mating with a better quality male.
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Affiliation(s)
- Gemma Morrow
- School of Zoology, University of Tasmania, Hobart, Tasmania, Australia
| | - Stewart C. Nicol
- School of Zoology, University of Tasmania, Hobart, Tasmania, Australia
- * E-mail:
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Rismiller PD, McKelvey MW. Activity and behaviour of lactating echidnas (Tachyglossus aculeatus multiaculeatus) from hatching of egg to weaning of young. AUST J ZOOL 2009. [DOI: 10.1071/zo09031] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Throughout their Australia-wide distribution, short-beaked echidnas breed during the winter months, i.e. June through early September. Actual duration of the female reproductive cycle, from attracting males and mating until weaning the young, can vary from 7 to 9 months depending on geographic location. Much of this variation is due to length of courtship and age of weaning the young. This paper presents data about the behaviour of free-ranging female echidnas on Kangaroo Island from egg laying through to weaning and compares it with findings from other areas. On Kangaroo Island, behaviour of lactating echidnas falls into two distinct phases: (1) while carrying the young in the pouch; and (2) after the young is placed in a nursery burrow. Females significantly increased both the number of hours active each day as well as the size of area utilised after the young was in the nursery. Although types of nursery burrows are similar throughout Australia, duration of use and frequency visited varies between geographic locations. A major difference is that Kangaroo Island echidnas are often active while carrying either the egg or the young in the pouch and echidnas in other regions remain in a burrow for extended periods.
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Riek A. Relationship between field metabolic rate and body weight in mammals: effect of the study. J Zool (1987) 2008. [DOI: 10.1111/j.1469-7998.2008.00482.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Smits G, Mungall AJ, Griffiths-Jones S, Smith P, Beury D, Matthews L, Rogers J, Pask AJ, Shaw G, VandeBerg JL, McCarrey JR, Renfree MB, Reik W, Dunham I. Conservation of the H19 noncoding RNA and H19-IGF2 imprinting mechanism in therians. Nat Genet 2008; 40:971-6. [PMID: 18587395 DOI: 10.1038/ng.168] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Accepted: 05/05/2008] [Indexed: 12/13/2022]
Abstract
Comparisons between eutherians and marsupials suggest limited conservation of the molecular mechanisms that control genomic imprinting in mammals. We have studied the evolution of the imprinted IGF2-H19 locus in therians. Although marsupial orthologs of protein-coding exons were easily identified, the use of evolutionarily conserved regions and low-stringency Bl2seq comparisons was required to delineate a candidate H19 noncoding RNA sequence. The therian H19 orthologs show miR-675 and exon structure conservation, suggesting functional selection on both features. Transcription start site sequences and poly(A) signals are also conserved. As in eutherians, marsupial H19 is maternally expressed and paternal methylation upstream of the gene originates in the male germline, encompasses a CTCF insulator, and spreads somatically into the H19 gene. The conservation in all therians of the mechanism controlling imprinting of the IGF2-H19 locus suggests a sequential model of imprinting evolution.
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Affiliation(s)
- Guillaume Smits
- The Babraham Institute, Laboratory of Developmental Genetics and Imprinting, Cambridge CB22 3AT, UK
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Nicol SC, Andersen NA. Rewarming rates and thermogenesis in hibernating echidnas. Comp Biochem Physiol A Mol Integr Physiol 2006; 150:189-95. [PMID: 17045501 DOI: 10.1016/j.cbpa.2006.08.039] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2006] [Revised: 08/15/2006] [Accepted: 08/18/2006] [Indexed: 11/22/2022]
Abstract
We measured body temperatures (T(b)) in 14 free-ranging echidnas (Tachyglossus aculeatus) using implanted data-loggers. An average of 1020+/-744 days of T(b) data was recorded from each animal. The average maximum T(b) was 35.3+/-0.7 degrees C (n=14), and the lowest T(b) was 4.7 degrees C. Detailed analysis of rewarming events from four echidnas showed rewarming time to be dependent on initial T(b) (rewarming time in hours=15.6-0.41T(initial), n=31) with an average rewarming rate of 1.9+/-0.4 degrees C h(-1). Based on an hourly sampling rate, the peak rewarming rate was found to be 7.2+/-0.8 degrees C h(-1) (n=12), which was measured at a mean T(b) of 26.2+/-2.4 degrees C. This rate of heating was calculated to be equivalent to a peak oxygen consumption rate of 1.4+/-0.2 ml O2 g h(-1), approximately 9 times the basal metabolic rate. We found that a plot of rate of change of T(b) against T(b) for the entire data set from an individual echidna provided a useful summary and analytical tool.
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Affiliation(s)
- Stewart C Nicol
- Anatomy and Physiology, University of Tasmania, Private Bag 24, Hobart, TAS 7001, Australia.
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Handasyde KA, McDonald IR, Evans BK. Plasma glucocorticoid concentrations in free-ranging platypuses (Ornithorhynchus anatinus): response to capture and patterns in relation to reproduction. Comp Biochem Physiol A Mol Integr Physiol 2004; 136:895-902. [PMID: 14667852 DOI: 10.1016/s1095-6433(03)00280-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Energy demands in the platypus are likely to increase in the breeding season, which occurs from winter to early spring. Glucocorticoids, which play a major role in energy mobilisation, were measured in consecutive blood samples from free-ranging adults at approximately monthly intervals throughout the year. Glucose and free fatty acids were also measured in some samples. Plasma concentrations of glucocorticoids rose significantly during the first 30 min after capture, accompanied by a rise in free fatty acids, but no corresponding increase in glucose concentrations. We observed a strong pattern in plasma glucocorticoids in samples collected within 15 min of capture (indicative of pre-disturbance concentrations) in different phases of the annual reproductive cycle, with significantly higher levels in both males and females in the breeding season compared to the non-breeding season. These data, and the decline in tail fat stores that occur towards the end of the mating period (around October), suggest that platypus experience high-energy demands during this phase of reproduction. Plasma glucocorticoid concentrations in females sampled during the lactation period (October-February) were relatively low, and similar to those in females sampled in the non-breeding, non-lactation period (March-June). The latter requires further investigation as results may have been influenced by sampling limitations.
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Affiliation(s)
- K A Handasyde
- Department of Zoology, University of Melbourne, Melbourne, Vic., 3010, Australia.
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