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

Abstract

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.

Plant diversity on the edge: floristics, phytogeography, fire responses, and plant conservation of Two Peoples Bay Nature Reserve in the context of OCBIL theory

“…However, the autumn lull declines to 0% in Chile and just a few per cent in California, Israel, South Australia, Jandakot south of Perth, and Kenwick in Perth's eastern suburbs (Bell and Stephens 1984). The 20% lull at the Reserve is quite generous in comparison, enabling survival of honey possums, which consume their own body weight in nectar and pollen every day of the year (Hopper 1981;Bradshaw and Bradshaw 2012).…”

Nectar uptake in bats using a pumping-tongue mechanism

“…Nectarivorous insects regularly consume floral nectar as their principal diet, whereas most nectar-feeding vertebrates are opportunistic users of floral resources. Accordingly and in contrast to many insects that have mouthparts specialized in nectarivory, very few obligate nectar-feeding birds (hummingbirds, honey eaters, and sunbirds) and mammals (the honey possum Tarsipes rostratus and various species of bats) show corresponding morphological specializations, mainly of the tongue ( 4 , 5 ).…”

Interrogating Phylogenetic Discordance Resolves Deep Splits in the Rapid Radiation of Old World Fruit Bats (Chiroptera: Pteropodidae)

“…Their early transition to a carbohydrate-rich plant-based diet is expected to have posed physiological and metabolic challenges, and several studies have uncovered molecular adaptations linked to diet ( Liu et al 2012 ; Sharma et al 2018 ; Jiao et al 2019 ; Wang et al 2020 ). In this context, of particular interest is the evolution of nectarivory in several pteropodid lineages (see Freeman 1995 ), a dietary specialization that in mammals is also seen in two lineages of Neotropical leaf-nosed bats (family Phyllostomidae) (e.g., Potter et al 2021 ) and the honey possum ( Bradshaw and Bradshaw 2012 ). To date, few studies of pteropodid bats have focused on nectarivorous lineages, which are promising models for studying metabolic adaptations due to their ability to subsist on simple sugars without developing glucose toxicity (e.g., Gutiérrez-Guerrero et al 2020 ; Potter et al 2021 ).…”