Tarsipes Research Articles

Pollination by birds, non-flying mammals, and European honeybees in a heathland shrub, Banksia catoglypta (Proteaceae)

Abstract Vertebrate pollination has evolved in many plant lineages, with pollination by birds the most prevalent strategy. However, in Banksia (Proteaceae) many species are visited by a combination of nectarivorous birds, non-flying mammals (NFMs), and insects, though the relative importance of these pollen vectors for reproduction remains poorly understood. Here, we investigate the contribution to fruit set of birds, NFMs, and insects in Banksia catoglypta—a heathland shrub from south-west Australia. This species flowers in winter and produces large, golden-yellow inflorescences that are typically presented near the ground and consist of rigid, strongly scented flowers with a long stigma-nectary distance—suggesting pollination by vertebrates. The primary floral visitors were white-cheeked honeyeaters (Phylidonyris niger), honey possums (Tarsipes rostratus), house mice (Mus musculus), and introduced European honeybees (Apis mellifera), all of which carried B. catoglypta pollen. Banksia catoglypta was found to be obligately outcrossing with no evidence of pollen limitation. Selective exclusion of flying pollinators revealed that inflorescences pollinated solely by NFMs produced 50% fewer fruit than open-pollinated controls. Therefore, while mammals are pollinators of B. catoglypta, they may contribute comparatively little to fruit set in some Banksia species displaying floral traits considered adaptations to NFM pollination. Exclusion of vertebrate pollinators had no effect on fruit set, demonstrating that European honeybees can be effective pollinators of some primarily vertebrate-pollinated plants.

The critical role of honeyeaters in the pollination of the catspaw Anigozanthos humilis (Haemodoraceae)

The pollination biology of Anigozanthos humilis (Haemodoraceae) was studied within a Banksia woodland reserve using a combination of field techniques and genetic analysis. Motion-triggered cameras were deployed on 25 flowering plants to identify visitors to flowers, quantify visitation rates and assess visitor behaviour. Entire A. humilis plants were caged to exclude potential floral visitors with six treatments: (i) bird and honey possum exclusion, allowing access by insects; (ii) bird and insect exclusion, allowing access by honey possums; (iii) total animal exclusion; (iv) open, allowing access by birds, insects and honey possums; (v) hand-pollination with cross-pollen; and (vi) hand-pollination with self-pollen. Open pollinated seed were genotyped to assess mating system parameters including outcrossing rate. From 23424 h of surveillance with camera traps, 109 visits were recorded, 106 (97%) of which were western spinebills (Acanthorhynchus superciliosus), with three visits by brown honeyeaters (Lichmera indistincta). We recorded an average of 8 (±4) visits per plant, equivalent to one visit every eleven days over the 2016 flowering season (mean = 63 days). Mean seed set per fruit was negligible (0.2–0.3 seed per fruit) for all pollination treatments except open- and hand-pollination with cross pollen. Mean seed set per fruit for hand cross-pollinated flowers (37.1 seed per fruit) was 37 times that of open pollinated flowers (1.0 seed per fruit). Outcrossing rate estimates were not significantly different to one. Our results indicate that at least for the study population and season, A. humilis was largely dependent on western spinebills for delivery of outcross pollen and resulting seed set, but visitation rates were low and pollen limitation was severe. Given the known sensitivity of western spinebills to habitat fragmentation, our results suggest flow on effects that may negatively impact on reproduction, and means that A. humilis may be particularly vulnerable to environmental changes that impact on bird pollinators.

Effectiveness of camera traps for quantifying daytime and nighttime visitation by vertebrate pollinators.

Identification of pollen vectors is a fundamental objective of pollination biology. The foraging and social behavior of these pollinators has profound effects on plant mating, making quantification of their behavior critical for understanding the ecological and evolutionary consequences of different pollinators for the plants they visit. However, accurate quantification of visitation may be problematic, especially for shy animals and/or when the temporal and spatial scale of observation desired is large. Sophisticated heat‐ and movement‐triggered motion‐sensor cameras (“camera trapping”) provide new, underutilized tools to address these challenges. However, to date, there has been no rigorous evaluation of the sampling considerations needed for using camera trapping in pollination research.We measured the effectiveness of camera trapping for identifying vertebrate visitors and quantifying their visitation rates and foraging behavior on Banksia menziesii (Proteaceae). Multiple still cameras (Reconyx HC 500) and a video camera (Little Acorn LTL5210A) were deployed.From 2,753 recorded visits by vertebrates, we identified five species of nectarivorous honeyeater (Meliphagidae) and the honey possum (Tarsipedidae), with significant variation in the species composition of visitors among inflorescences. Species of floral visitor showed significant variation in their time of peak activity, duration of visits, and numbers of flowers probed per visit. Where multiple cameras were deployed on individual inflorescences, effectiveness of individual still cameras varied from 15% to 86% of all recorded visits. Methodological issues and solutions, and the future uses of camera traps in pollination biology, are discussed. Conclusions and wider implications: Motion‐triggered cameras are promising tools for the quantification of vertebrate visitation and some aspects of behavior on flowers. However, researchers need to be mindful of the variation in effectiveness of individual camera traps in detecting animals. Pollinator studies using camera traps are in their infancy, and the full potential of this developing technology is yet to be realized.

Long-term recovery from fire by a population of honey possums (Tarsipes rostratus) in the extreme south-west of Western Australia

The impact of two fires, six years apart, on the long-term recovery of a population of honey possums (Tarsipes rostratus) in the extreme south-west of Western Australia was documented over a 23-year period. Recovery was relatively rapid after the first fire, with catch rates reaching 78% of precatch levels within six years, but was much slower following the second fire in April 1999. Regression analysis estimates that full recovery to prefire catch rates and densities would take 25.6 years. The spread of Phytophthora cinnamomi (dieback) throughout the study area has severely impacted Banksia ilicifolia trees, which are the honey possums’ primary food source, and the impact has been greater in the burnt than unburnt areas. Analysis of catch-per-unit-effort and density of individual honey possums over the whole 29-year period of the study shows that numbers have not declined in the long-unburnt southern area of the study site, despite the spread of dieback and loss of banksia trees. The data are discussed in relation to the impact of fire on other vertebrate species that have specific habitat requirements. Given predictions of increasing fire frequencies due to climate change and an increased utilisation of prescribed burning to protect human life and property, it is imperative that management of areas harbouring honey possums be protected from too-frequent fire if this iconic species is to persist.

The plant pathogen Phytophthora cinnamomi influences habitat use by the obligate nectarivore honey possum (Tarsipes rostratus)

Introduced plant pathogens can devastate susceptible plant communities, and consequently impact on animal communities reliant on plants for food and habitat. Specifically, plant pathogens change the floristic diversity of vegetation communities, thereby reducing availability of food sources for fauna (e.g. pollen and nectar) and result in major changes to habitat structure when canopy and understorey plant species succumb to disease. Phytophthora cinnamomi poses a threat to flowering plant species (e.g. Banksia species) which are important food sources for nectarivorous fauna. The honey possum (Tarsipes rostratus) is the only obligate nectarivorous non-flying mammal living on a restrictive diet of nectar and pollen; consequently, these tiny mammals are likely to be particularly vulnerable to the landscape-wide devastation caused by P. cinnamomi. We investigated habitat selection by honey possums in a vegetation community infested with P. cinnamomi to determine how these mammals respond to habitat affected by this pathogen. Over four seasons, 18 honey possums were fitted with radio-transmitters and tracked to identify habitat preferences. Vegetation surveys were compared for locations selected by honey possums (as determined from tracking) and randomly selected sites. Radio-tracking revealed that sites selected by honey possums were significantly taller, denser, and more floristically diverse than their paired random locations. The presence of P. cinnamomi influences habitat use by honey possums, but animals show resilience in terms of using the best of what is available in both P. cinnamomi–affected and unaffected locations. Habitat patches comprising less susceptible species, or plants that have yet to succumb to infection, provide refuge and food resources for honey possums. Management to reduce the spread of existing P. cinnamomi infestations and prevent contamination of new locations will benefit vegetation communities and associated faunal communities, while identifying honey possum food plant species that are resilient to the pathogen may support revegetation attempts.

Guidelines for ecological burning regimes in Mediterranean ecosystems: a case study in Banksia woodlands in Western Australia.

In Mediterranean ecosystems prescribed burning is commonly employed to reduce the risk or intensity of wildfires. As a consequence, a major challenge for conservation land managers is the development of fire regimes that reduce damaging wildfires and are optimal for biodiversity. The aim of this paper was to develop guidelines for ecological fire regimes using the Banksia woodland on the Gnangara Groundwater System in Western Australia as a case study. Development of the guidelines involved the determination of maximum and minimum fire intervals of key fire response species, analyses of fire history records and estimation of ideal age class distributions at the landscape level. Recommendations included a) adoption of a minimum fire interval of 8–16 years, b) implementation of a burning regime to redress the current skewed distribution (60%: 1–7 years since last fire), c) retention of long-unburnt habitats that are significant for species such as the critically endangered Calyptorhynchus latirostris (Carnaby’s black-cockatoo), and Tarsipes rostratus (honey possum), and d) protection for wetlands that can serve as fire ‘refugia’ for associated species, such as Isoodon obesulus fusciventer (southern brown bandicoot or quenda). The guidelines developed provide a model for the development of ecological burning regimes in other similar ecosystems. The implementation of ecological guidelines normally involves incorporation into fire management planning by fire agencies and often entails complex solutions to conflicting aims. The guidelines are thus valuable for ecologists and land managers, especially in light of an expected significant increase in global fire activity as a consequence of predicted climate change.

Flower visitation by honey possums (Tarsipes rostratus) in a coastal banksia heathland infested with the plant pathogen Phytophthora cinnamomi

The honey possum (Tarsipes rostratus) is a tiny (7–10 g) obligate nectarivore endemic to south-west Western Australia that relies on high floristic diversity for year-round nectar and pollen resources. We investigated flower visitation by honey possums at a site in the presence of the plant pathogen Phytophthora cinnamomi by sampling pollen on the head of captured and radio-tracked individuals. The aim of the study was to identify plant species that were visited and to compare these with known susceptibility to Phytophthora to assess the potential impact of further spread of the pathogen on honey possums. Nine plant taxa were regularly identified from pollen on honey possums, including four Banksia species. Six of the nine plant taxa identified (Banksia plumosa, Adenanthos cuneatus, Calothamnus gracilis, B. brunnea, B. nutans, B. tenuis) were most frequently visited by honey possums, each making up >20% of pollen grains for at least one season. Five of the nine plant taxa are known to be susceptible to Phytophthora, which substantially changes vegetation composition in its wake. The inevitable spread of Phytophthora is postulated to result in the localised loss of resources for honey possums and is a concern for on-going conservation management.

Terrestrial mammals of the Gnangara Groundwater System, Western Australia: history, status, and the possible impacts of a drying climate

Over the last 30 years declining rainfall and increased aquifer abstraction have heavily impacted water availability and ecosystems on the Gnangara Groundwater System (GGS). The mammal fauna of the area is considered to have been rich, with up to 28 terrestrial and 5 volant native species recorded since European settlement. This study investigated previous and current distribution of mammals on the GGS, and assessed potential impacts of predicted rainfall and groundwater declines on mammals. A general survey was conducted at 40 sites, and targeted trapping was undertaken for Hydromys chrysogaster and Isoodon obesulus fusciventer at wetlands. Nine native and seven introduced terrestrial mammal species were recorded during the general survey and capture rates were very low (1.05%). The most commonly captured native species was Tarsipes rostratus. There is evidence that only 11 (9 recorded and 2 considered to be extant) of the 28 historically recorded terrestrial native mammals still persist in the area. The species predicted to be most susceptible to rainfall and groundwater level declines include H. chrysogaster, I. obesulus fusciventer, and T. rostratus. Management and recovery actions required to protect mammals under predicted climatic changes include identification and maintenance of refugia and ecological linkages, supplementation of lakes, development of ecologically appropriate fire regimes, and control of predators.

The physiology of the honey possum, Tarsipes rostratus, a small marsupial with a suite of highly specialised characters: a review

Field and laboratory studies of the iconic nectarivorous and 'pollenivorous' honey possum, Tarsipes rostratus, are reviewed with the aim of identifying aspects of its physiology that are as yet poorly understood and needed to implement management strategies for its long-term conservation. Dietary specialisations include the loss of teeth, a modified gut with a high rate of passage, exceptionally low minimum nitrogen requirements, an apparently high basal metabolic rate and a permanently polyuric kidney. In contrast, its reproductive physiology is plesiomorphic, combining aspects such as a post-partum oestrus, embryonic diapause, photoperiodicity and extended maternal care that are usually separate characteristics of other marsupial groups. In common with a number of other marsupials, the honey possum has the potential for trichromatic colour vision and has been the subject of several studies attempting to correlate visual quality with ecological realities. Field physiological studies have established its high rates of nectar and pollen intake needed to maintain energy balance and highlight the need for a constant intake from floral sources. Early allometric studies suggesting that the honey possum's relatively low reproductive rate may be linked to a diet limited in protein have not been supported and nitrogen intakes in the field exceed by a factor of 10 the animal's basic requirements for balance. Measurements of rates of protein turnover in field-caught lactating females suggest that they divert nitrogen from the protein pool to milk production by reducing rates of degradation, rather than by increasing rates of synthesis of protein. Although not yet an endangered species, the honey possum's habitat has been drastically reduced since European occupation of Australia and future-targeted research on the animal's unique physiology and habitat linkage is needed that can be translated into effective management practices. Only then will its long-term survival be assured.

Diversity of Color Vision: Not All Australian Marsupials Are Trichromatic

Color vision in marsupials has recently emerged as a particularly interesting case among mammals. It appears that there are both dichromats and trichromats among closely related species. In contrast to primates, marsupials seem to have evolved a different type of trichromacy that is not linked to the X-chromosome. Based on microspectrophotometry and retinal whole-mount immunohistochemistry, four trichromatic marsupial species have been described: quokka, quenda, honey possum, and fat-tailed dunnart. It has, however, been impossible to identify the photopigment of the third cone type, and genetically, all evidence so far suggests that all marsupials are dichromatic. The tammar wallaby is the only Australian marsupial to date for which there is no evidence of a third cone type. To clarify whether the wallaby is indeed a dichromat or trichromatic like other Australian marsupials, we analyzed the number of cone types in the “dichromatic” wallaby and the “trichromatic” dunnart. Employing identical immunohistochemical protocols, we confirmed that the wallaby has only two cone types, whereas 20–25% of cones remained unlabeled by S- and LM-opsin antibodies in the dunnart retina. In addition, we found no evidence to support the hypothesis that the rod photopigment (rod opsin) is expressed in cones which would have explained the absence of a third cone opsin gene. Our study is the first comprehensive and quantitative account of color vision in Australian marsupials where we now know that an unexpected diversity of different color vision systems appears to have evolved.

Metabolic, hygric and ventilatory physiology of a hypermetabolic marsupial, the honey possum (Tarsipes rostratus)

The honey possum is the only non-volant mammal to feed exclusively on a diet of nectar and pollen. Like other mammalian and avian nectarivores, previous studies indicated that the honey possum's basal metabolic rate was higher than predicted for a marsupial of equivalent body mass. However, these early measurements have been questioned. We re-examined the basal metabolic rate (2.52 +/- 0.222 ml O(2) g(-1) h(-1)) of the honey possum and confirm that it is indeed higher (162%) than predicted for other marsupials both before and after accounting for phylogenetic history. This, together with its small body mass (5.4 +/- 0.14 g; 1.3% of that predicted by phylogeny) may be attributed to its nectarivorous diet and mesic distribution. Its high-basal metabolic rate is associated with a high-standard body temperature (36.6 +/- 0.48 degrees C) and oxygen extraction (19.4%), but interestingly the honey possum has a high point of relative water economy (17.0 degrees C) and its standard evaporative water loss (4.33 +/- 0.394 mg H(2)O g(-1) h(-1)) is not elevated above that of other marsupials, despite its mesic habitat and high dietary water intake.

Measurement of the rate of protein turnover and synthesis in the marsupial Honey possum (Tarsipes rostratus)

Rates of protein turnover and synthesis were measured in wild-caught Honey possums (Tarsipes rostratus) in the southwest of Western Australia and compared between males and females with and without pouch young. Possums were injected with 50 microg of (15)N-glycine and ammonia collected within 24 h was used as the nitrogen end-product in a single-injection protocol. The overall mean rate of protein synthesis measured was 7.7+/-0.5 g kg(-0.75) day(-1), which falls within the range of values reported for other marsupial species. Whole body rates of nitrogen flux and protein synthesis did not vary significantly between males and females with and without young, but females with pouch young showed significantly lower rates of protein synthesis when expressed in relation to metabolic body size. This difference was no longer apparent, however, if the mass of the females was corrected for the estimated mass of the young in the pouch averaging 9.3+/-1.6 g kg(-0.75) day(-1) and suggesting that the young should not be considered as part of the metabolic body pool. Whole body rates of protein degradation were significantly reduced in females carrying pouch young, suggesting that protein may be being diverted from the pool to milk production. Calculations indicate that the daily fraction of the female's nitrogen synthesis rate that needs to be diverted to pouch young to sustain their growth is less than 5%, and may not be detectable with the current methodology.

Cone visual pigments in two marsupial species: the fat-tailed dunnart (Sminthopsis crassicaudata) and the honey possum (Tarsipes rostratus)

Uniquely for non-primate mammals, three classes of cone photoreceptors have been previously identified by microspectrophotometry in two marsupial species: the polyprotodont fat-tailed dunnart (Sminthopsis crassicaudata) and the diprotodont honey possum (Tarsipes rostratus). This report focuses on the genetic basis for these three pigments. Two cone pigments were amplified from retinal cDNA of both species and identified by phylogenetics as members of the short wavelength-sensitive 1 (SWS1) and long wavelength-sensitive (LWS) opsin classes. In vitro expression of the two sequences from the fat-tailed dunnart confirmed the peak absorbances at 363 nm in the UV for the SWS1 pigment and 533 nm for the LWS pigment. No additional expressed cone opsin sequences that could account for the middle wavelength cones could be amplified. However, amplification from the fat-tailed dunnart genomic DNA with RH1 (rod) opsin primer pairs identified two genes with identical coding regions but sequence differences in introns 2 and 3. Uniquely therefore for a mammal, the fat-tailed dunnart has two copies of an RH1 opsin gene. This raises the possibility that the middle wavelength cones express a rod rather than a cone pigment.

Encephalization of Australian and New Guinean Marsupials

Encephalization of Australian marsupials was analyzed using the endocranial volume (ECV) of 52 species of Dasyuromorphia and Notoryctemorphia, 14 species of Peramelemorphia and 116 species of Diprotodontia from Australia and New Guinea and compared with 16 species of Ameridelphian marsupials and 3 species of native and recently introduced Australian eutherian carnivores (dingo, feral cat and feral fox). Linear regression analysis of the relationship between ECV and body weight for marsupials revealed that allometric parameters for these groups are different from those previously derived for samples of (mainly eutherian) mammals, with higher slopes for Dasyuromorphia and Diprotodontia and lower slopes for Ameridelphians and Peramelemorphia. Absolute ECV for small Australian and New Guinea marsupial carnivores (Antechinus and Sminthopsis) were found to be comparable to eutherians of similar body weight, but large marsupial carnivores such as the Tasmanian devil and thylacine had substantially smaller ECVs than eutherian carnivores of similar body weight. Similarly, members of some superfamilies within Diprotodontia (Burramyoidea, Petauroidea, Tarsipedoidea) had ECVs comparable to prosimians, whereas bandicoots, bilbies and many macropods were found to be poorly encephalized. When both encephalization quotient (EQ) and residuals from regression analysis were used to compare relative ECV of extinct/threatened species with common species there were no significant differences for any of the orders of Australian marsupials, suggesting that encephalization is not a major factor in the current extinction crisis for Australian marsupials. Similarly there were no consistent differences in relative ECV between marsupials from New Guinea and associated islands compared to Australia or between arid and non-arid Australian regions for any of the marsupial orders. The results indicate that marsupials are not uniformly poorly encephalized and that small marsupial carnivores and some members of Diprotodontia are of comparable encephalization to eutherians of similar body weight. In particular, honey possums and some gliders show an encephalization level comparable to prosimians, perhaps reflecting convergence in adaptation to similar arboreal niches.

Family-level relationships among the Australasian marsupial “herbivores” (Diprotodontia: Koala, wombats, kangaroos and possums)

The marsupial order Diprotodontia includes 10 extant families, which occupy all terrestrial habitats across Australia and New Guinea and have evolved remarkable dietary and locomotory diversity. Despite considerable attention, the interrelations of these families have for the most part remained elusive. In this study, we separately model mitochondrial RNA and protein-coding sequences in addition to nuclear protein-coding sequences to provide near-complete resolution of diprotodontian family-level phylogeny. We show that alternative topologies inferred in some previous studies are likely to be artifactual, resulting from branch-length and compositional biases. Subordinal groupings resolved herein include Vombatiformes (wombats and koala) and Phalangerida, which in turn comprises Petauroidea (petaurid gliders and striped, feathertail, ringtail and honey possums) and a clade whose plesiomorphic members possess blade-like premolars (phalangerid possums, kangaroos and their allies and most likely, pygmy possums). The topology resolved reveals ecological niche structuring among diprotodontians that has likely been maintained for more than 40 million years.

Allometry, Antilog Transformations, and the Perils of Prediction on the Original Scale

Previous article No AccessErratumAllometry, Antilog Transformations, and the Perils of Prediction on the Original ScaleJack P. Hayes, and J. Scott Shonkwiler Jack P. HayesPhysiological and Biochemical Zoology 79:665–674 (2006) Search for more articles by this author , and J. Scott ShonkwilerPhysiological and Biochemical Zoology 79:665–674 (2006) Search for more articles by this author Physiological and Biochemical Zoology 79:665–674 (2006)Original articleAllometry, Antilog Transformations, and the Perils of Prediction on the Original ScalePDFPDF PLUSFull Text Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by Physiological and Biochemical Zoology Volume 80, Number 5September/October 2007 Sponsored by Division of Comparative Physiology and Biochemistry, Society for Integrative and Comparative Biology Article DOIhttps://doi.org/10.1086/520866 Views: 9Total views on this site Citations: 12Citations are reported from Crossref © 2007 by The University of Chicago. All rights reserved.PDF download Crossref reports the following articles citing this article:J. M. Barker, C. E. Cooper, P. C. Withers, and S. C. Nicol Reexamining Echidna Physiology: The Big Picture for Tachyglossus aculeatus acanthion, Physiological and Biochemical Zoology 89, no.33 (Apr 2016): 169–181.https://doi.org/10.1086/686716Hannah Pusey, Christine E. Cooper, Philip C. Withers Metabolic, hygric and ventilatory physiology of the red-tailed phascogale (Phascogale calura; Marsupialia, Dasyuridae): Adaptations to aridity or arboreality?, Mammalian Biology 78, no.66 (Nov 2013): 397–405.https://doi.org/10.1016/j.mambio.2012.11.008Justine M. Barker, Christine E. Cooper, Philip C. Withers, Ariovaldo P. Cruz-Neto Thermoregulation by an Australian murine rodent, the ash-grey mouse (Pseudomys albocinereus), Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology 163, no.3-43-4 (Nov 2012): 336–342.https://doi.org/10.1016/j.cbpa.2012.07.011Philip C. Withers, Christine E. Cooper, Roberto F. Nespolo Evaporative water loss, relative water economy and evaporative partitioning of a heterothermic marsupial, the monito del monte ( Dromiciops gliroides ), Journal of Experimental Biology 215, no.1616 (Aug 2012): 2806–2813.https://doi.org/10.1242/jeb.070433A.J. Munn, C.E. Cooper, B. Russell, T.J. Dawson, S.R. McLeod, S.K. Maloney Energy and water use by invasive goats (Capra hircus) in an Australian rangeland, and a caution against using broad-scale allometry to predict species-specific requirements, Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology 161, no.22 (Feb 2012): 216–229.https://doi.org/10.1016/j.cbpa.2011.10.027Christine E. Cooper, Philip C. Withers Comparative physiology of Australian quolls (Dasyurus; Marsupialia), Journal of Comparative Physiology B 180, no.66 (Mar 2010): 857–868.https://doi.org/10.1007/s00360-010-0452-3C. E. Cooper, P. C. Withers, A. P. Cruz-Neto Metabolic, ventilatory, and hygric physiology of a South American marsupial, the long-furred woolly mouse opossum, Journal of Mammalogy 91, no.11 (Feb 2010): 1–10.https://doi.org/10.1644/09-MAMM-A-138R.1S. Schmidt, P.C. Withers, C.E. Cooper Metabolic, ventilatory and hygric physiology of the chuditch (Dasyurus geoffroii; Marsupialia, Dasyuridae), Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology 154, no.11 (Sep 2009): 92–97.https://doi.org/10.1016/j.cbpa.2009.05.002Christine Elizabeth Cooper, Ariovaldo P. Cruz-Neto Metabolic, hygric and ventilatory physiology of a hypermetabolic marsupial, the honey possum (Tarsipes rostratus), Journal of Comparative Physiology B 179, no.66 (Apr 2009): 773–781.https://doi.org/10.1007/s00360-009-0358-0Philip C. Withers, Christine E. Cooper Thermal, metabolic, hygric and ventilatory physiology of the sandhill dunnart (Sminthopsis psammophila; Marsupialia, Dasyuridae), Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology 153, no.33 (Jul 2009): 317–323.https://doi.org/10.1016/j.cbpa.2009.03.006P. C. Withers, C. E. Cooper Thermal, Metabolic, and Hygric Physiology of the Little Red Kaluta, Dasykaluta rosamondae (Dasyuromorphia: Dasyuridae), Journal of Mammalogy 90, no.33 (Jun 2009): 752–760.https://doi.org/10.1644/08-MAMM-A-286R.1C. E. Cooper, P. C. Withers, and A. P. Cruz‐Neto Metabolic, Ventilatory, and Hygric Physiology of the Gracile Mouse Opossum (Gracilinanus agilis) C. E. Cooper, P. C. Withers, and A. P. Cruz‐Neto, Physiological and Biochemical Zoology 82, no.22 (Jul 2015): 153–162.https://doi.org/10.1086/595967Related articlesAllometry, Antilog Transformations, and the Perils of Prediction on the Original Scale19 Jul 2015Physiological and Biochemical Zoology

The unique paired retinal vascular pattern in marsupials: structural, functional and evolutionary perspectives based on observations in a range of species

Background:In the few marsupial species studied to date that possess a retinal vasculature, the arterial and venous segments, down to the smallest calibre capillaries, have been shown to occur in...

Isotopic Measurements of Field Metabolic Rate (FMR) in the Marsupial Honey Possum (Tarsipes rostratus)

Abstract The doubly labeled water (DLW) method for the measurement of the field metabolic rate (FMR) of free-ranging vertebrates has limitations that are most evident when dealing with very small mammals, such as the nectarivorous marsupial honey possum (Tarsipes rostratus), that exhibit high metabolic rates and elevated rates of water turnover. We tested the efficacy of the radioisotope rubidium-86 (86Rb) as an alternative method for estimating FMR in this species in winter in Scott National Park in extreme southwestern Western Australia. We carried out a trial with 58 honey possums injected with a cocktail containing 86Rb, tritium, and oxygen-18 and correlated estimates of the FMR using the DLW method with repetitive measurements of the biological elimination rate constant (kb) of 86Rb. The 2 variables were significantly correlated and a linear regression explained 86% of the variation, which increased to 91% with a power curve fit to the data. Successive measurements of kb in individuals that were repe...

Ecology of the Honey possum, Tarsipes rostratus, in Scott National Park, Western Australia

The Honey possum, Tarsipes rostratus, is an obligate nectarivore, known to feed on plant species from only three Families in south-western Western Australia: Myrtaceae, Proteaceae and Epacridaceae. These plants can be adversely affected by fire, decreased rainfall or groundwater levels and the pathogen Phytophthora cinnamomi. We investigated the ecology of T. rostratus in terms of: (i) how the population fluctuated in response to rainfall and fire over a 20-year period and (ii) changes in diet and movements during a period of decreased food availability in late summer. Mean capture rates were significantly positively correlated with mean flowering rates of Banksia ilicifolia over a 20-year period. Winter capture rates were also significantly positively correlated with both annual and winter rainfall two years prior to trapping in recently burnt areas, but not in long unburnt� areas. Capture rates were significantly higher in unburnt Banksia woodland during winter but densities there have declined since 1996, associated with the death of many Banksia ilicifolia trees from persistent Phytophthora infection. Notwithstanding this decline, winter capture rates in the unburnt areas were still approximately double those in the burnt areas 6 years after the last fire. Short-term capture rates were negatively correlated with barometric pressure, showing that movement and foraging is stimulated by the passage of low pressure frontal weather systems. Despite the paucity of known food sources flowering in late summer and autumn, there was no evidence of T. rostratus using plant species from other than the three above-noted Families. Utilisation areas in summer were also no larger than those previously recorded across all seasons in Scott National Park. Some individuals, however, moved extensive distances to locate spatially restricted food sources. The conservatism of their diet and the sensitivity of the population to changes in rainfall and fire history indicate that T. rostratus populations are particularly vulnerable to some of the environmental changes now occurring in south-western Australia.

Reproduction and embryonic diapause in a marsupial: Insights from captive female Honey possums, Tarsipes rostratus (Tarsipedidae)

The reproductive physiology of the polyoestrous Honey possum ( Tarsipes rostratus) is virtually unknown except that it shares with the kangaroos and wallabies the phenomenon of embryonic diapause. Its tiny size necessitates an alternate approach to study their reproductive cycle. We have accordingly utilised faecal steroid analysis. Baseline faecal cortisol levels in the Honey possum, at 4.1 ± 0.3 μg g −1, are approximately 100-fold those of other mammals and are associated with adrenal glands that, on a mass-specific basis, are almost 10 times larger than the adrenals of other mammalian, including marsupial, species. Histological examination of the adrenal glands revealed no abnormalities, however, but their hypertrophy and the peaks recorded in faecal levels following disturbance suggest that the Honey possum is vulnerable to chronic stressors in the captive situation. Mean faecal progestagens (124.4 ± 107.3 ng g −1) and oestradiol-17β (4.1 ± 1.1 ng g −1) in 4 non-pregnant females maintained long term were not different from those of 5 pregnant females (101.4 ± 61.0 ng g −1 and 4.3 ± 1.5 ng g −1, respectively) and, on analysis, revealed a cyclicity of 24 ± 1.2 days. We would predict from this evidence that the gestation period, in the absence of lactation, is approximately 23 days. Four of the pregnant females, monitored from July to November under conditions of 10:14 L:D photoperiod, showed a fall in levels of progestagens from 175.9 ± 10.8 ng g −1 in July and August to 30.9 ± 9.4 ng g −1 in October, while mean faecal levels of oestradiol-17β increased from 3.8 ± 0.4 ng g −1 in July to 5.7 ± 0.3 ng g −1 in October. September and October are months of peak reproductive activity in the wild and we suggest that these hormonal modulations may represent an entrained reproductive rhythm. Blastocysts appear to develop at varying rates, both within the one uterus, and between the two uteri of a single female. In addition, the time taken to reach the blastocyst stage may be longer than in any other marsupial studied to date. An association of the age of the pouch young with the stage reached by the developing blastocyst does not support the conclusion that blastocysts, once formed, grow slowly during lactation or diapause. Contrary to previous reports, we have documented what appears to be a lactational inhibition on blastocysts in diapause and have estimated the length of the ‘delayed’ reproductive cycle in two females as less than 2 weeks. Reactivation of blastocysts in Tarsipes has been shown to be stimulated by shortening day lengths after the summer solstice, a response similar to the annual breeding period of macropodid marsupials. Results from studying Honey possums in captive conditions suggest that the control of diapause in Tarsipes appears to be three-fold; lactational, photoperiodic and an entrained rhythm.