The influence of reproductive hormones on the torpor patterns of the marsupial Sminthopsis macroura: Bet-hedging in an unpredictable environment

McAllan, Bronwyn M.; Feay, N.; Bradley, A. J.; Geiser, Fritz

doi:10.1016/j.ygcen.2012.08.024

Cited by 18 publications

(18 citation statements)

References 75 publications

(129 reference statements)

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“…Oestrous cycling of females was determined by monitoring changes in vaginal epithelial cells in smears of the urogenital sinus (Nalbandov, 1976;Pollock et al, 2010). The presence of a large number of cornified epithelial cells in the urine, as well as a sharp increase in body mass, indicated the peak of oestrous (Woolley, 1990;Selwood and Woolley, 1991;Czarny et al, 2009;McAllan et al 2012). A male was introduced into the cage of a female at this point, and the first day that sperm were detected in urine of the female was designated day 1 after mating (Selwood and Woolley, 1991;Roberts and Breed, 1996).…”

Section: Animal Husbandrymentioning

confidence: 99%

“…A male was introduced into the cage of a female at this point, and the first day that sperm were detected in urine of the female was designated day 1 after mating (Selwood and Woolley, 1991;Roberts and Breed, 1996). Paired females were monitored for signs of pregnancy, including an increase in pouch area and vascularization, loss of the furred pouch lining, and an increase in body mass (Woolley, 1990;McAllan et al 2012). Gestation was confirmed by the presence of embryos in excised uteri, and embryo size and morphology were used to construct a timeline of embryonic development for S. crassicaudata based on the timeline for S. macroura (Selwood and Woolley, 1991;Cruz and Selwood, 1997).…”

Section: Animal Husbandrymentioning

confidence: 99%

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Uterine epithelial cell changes during pregnancy in a marsupial (Sminthopsis crassicaudata; Dasyuridae)

Laird

Thompson

Murphy

et al. 2014

Journal of Morphology

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Formation of a placenta requires intimate contact between the embryonic and maternal uterine epithelia in early pregnancy. Contact is accompanied by a characteristic suite of changes to the plasma membranes of uterine epithelial cells, termed the plasma membrane transformation. The plasma membrane transformation occurs in eutherian mammals and in viviparous (live-bearing) squamate reptiles, and may be fundamental to the evolution of viviparity in amniotes. Marsupials provide an excellent opportunity to test the generality of this phenomenon. Here, we present the first detailed study of the plasma membrane transformation in a marsupial. We combine electron microscopy and immunohistochemistry to describe morphological and molecular features of uterine epithelial cells during pregnancy in the fat-tailed dunnart (Sminthopsis crassicaudata; Dasyuridae). Cell morphology changes dramatically in S. crassicaudata during pregnancy. Apical microvilli are replaced by irregular blunt projections, then by spiky projections postimplantation. Cell surfaces flatten and ciliated cells are lost. Junctional complexes between adjacent cells increase in depth, then decrease just before implantation, which is consistent with junctional protein localization in this region of the cell membrane. The uterine cellular changes in S. crassicaudata are consistent with a plasma membrane transformation, and support the idea that this phenomenon is fundamental to the evolution of viviparity in amniote vertebrates.

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Section: Animal Husbandrymentioning

confidence: 99%

Section: Animal Husbandrymentioning

confidence: 99%

Uterine epithelial cell changes during pregnancy in a marsupial (Sminthopsis crassicaudata; Dasyuridae)

Laird

Thompson

Murphy

et al. 2014

Journal of Morphology

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“…In our study, the combined uterus and ovary mass decreased by ∼70% in the SP in comparison to the LP group. It is known that in the season, in which torpor is expressed in heterothermic mammals, reproductive activity is often halted and reproductive organs regress, but this is not the case for all species [33]–[38].…”

Section: Discussionmentioning

confidence: 99%

A Functional Nexus between Photoperiod Acclimation, Torpor Expression and Somatic Fatty Acid Composition in a Heterothermic Mammal

2013

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The seasonal changes in thermal physiology and torpor expression of many heterothermic mammals are controlled by photoperiod. As function at low body temperatures during torpor requires changes of tissue lipid composition, we tested for the first time whether and how fatty acids are affected by photoperiod acclimation in hamsters, Phodopus sungorus, a strongly photoperiodic species. We also examined changes in fatty acid composition in relation to those in morphology and thermal biology. Hamsters in short photoperiod had smaller reproductive organs and most had a reduced body mass in comparison to those in long photoperiod. Pelage colour of hamsters under short photoperiod was almost white while that of long photoperiod hamsters was grey-brown and black. Short photoperiod acclimation resulted in regular (28% of days) torpor use, whereas all hamsters in long photoperiod remained normothermic. The composition of total fatty acids differed between acclimation groups for brown adipose tissue (5 of 8 fatty acids), heart muscle (4 of 7 fatty acids) and leg muscle (3 of 11 fatty acids). Importantly, 54% of all fatty acids detected were correlated (r2 = 0.60 to 0.87) with the minimum surface temperature of individuals, but the responses of tissues differed. While some of the compositional changes of fatty acids were consistent with a ‘homeoviscous’ response, this was not the case for all, including the sums of saturated and unsaturated fatty acids, which did not differ between acclimation groups. Our data identify a possible nexus between photoperiod acclimation, morphology, reproductive biology, thermal biology and fatty acid composition. They suggest that some of the changes in thermal physiology are linked to the composition of tissue and organ fatty acids.

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“…The body mass and tail width of dunnarts were measured at the beginning, the middle, and the end of acclimation, and at the end of each experimental or washout period using an electronic balance to 0.01 g (Industrial and Scientific Supply Company Pty Ltd). Tail widths, which are an indicator of fattening and body condition (McAllan, Feay, Bradley, & Geiser, ), were measured using vernier calipers (Dick Smith Electronic calipers).…”

Section: Methodsmentioning

confidence: 99%

“…Tail widths, which are an indicator of fattening and body condition (McAllan, Feay, Bradley, & Geiser, 2012), were measured using vernier calipers (Dick Smith Electronic calipers).…”

Section: Body Mass and Tail Width Measurementsmentioning

confidence: 99%

Dietary protein supplementation and its consequences for intake, digestion, and physical activity of a carnivorous marsupial, Sminthopsis crassicaudata

Yuan

Wilder

Raubenheimer

et al. 2018

Ecology and Evolution

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Diet regulation behavior can mediate the consequences of imbalanced diets for animal well‐being, particularly for captive species that have little dietary choice. Dasyurids (carnivorous marsupials) are of conservation concern in Australia, and many species are in captive breeding programmes. However, their nutrient targets and dietary regulation behaviors are poorly understood, a limitation that may decrease the breeding success and well‐being of captive animals. We tested how dietary protein content influenced the intake and utilization of nutrients, physical activity, and body mass of fat‐tailed dunnarts Sminthopsis crassicaudata. Twelve adult dunnarts from six sibling pairs (one female and one male per pair) were provided ad libitum access to three diets in a repeated measures design: cat food, cat food supplemented with raw lean beef (1:1), and cat food supplemented with cooked lean beef (1:1). Food intake, activity level, and fecal output were measured daily. Dunnarts significantly decreased food intake, increased protein digestion, and physical activity, but body mass was unchanged when on the high‐protein diet compared to the normal cat food diet. These observations suggest a capacity of dunnarts to maintain constant body mass using a dynamic balance of feeding, digestion, and activity. We also found a significant effect of family, with differences between families as large as the difference between the diet treatments, suggesting a genetic component to diet selection. The nutrient regulation responses of dunnarts to high‐protein diets and the strong family effects provide important messages for the management of populations of small carnivores, including the aspects of dietary manipulation and conservation of genetic diversity.

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The influence of reproductive hormones on the torpor patterns of the marsupial Sminthopsis macroura: Bet-hedging in an unpredictable environment

Cited by 18 publications

References 75 publications

Uterine epithelial cell changes during pregnancy in a marsupial (Sminthopsis crassicaudata; Dasyuridae)

Uterine epithelial cell changes during pregnancy in a marsupial (Sminthopsis crassicaudata; Dasyuridae)

A Functional Nexus between Photoperiod Acclimation, Torpor Expression and Somatic Fatty Acid Composition in a Heterothermic Mammal

Dietary protein supplementation and its consequences for intake, digestion, and physical activity of a carnivorous marsupial, Sminthopsis crassicaudata

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