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Accueil du site → Doctorat → Australie → Physiological and behavioural responses of Western Australian dunnarts (Sminthopsis spp.) to energetic challenge

University of Western Australia (2011)

Physiological and behavioural responses of Western Australian dunnarts (Sminthopsis spp.) to energetic challenge

Tomlinson Sean

Titre : Physiological and behavioural responses of Western Australian dunnarts (Sminthopsis spp.) to energetic challenge

Auteur : Tomlinson Sean

Université de soutenance : University of Western Australia

Grade : Doctor of Philosophy (PhD) 2011

Présentation
[Truncated abstract] The general rationale of this thesis is to compare the physiological and behavioural flexibilities of a small mammal with a large and ecologically variable distribution with those of a comparable species with a comparatively small and homogeneous distribution. The Stripe-faced Dunnart (Sminthopsis macroura) is distributed across most of the northern half of Australia, covering arid and semi arid woodlands, shrublands and savannah and tussock grasslands. The Ooldea Dunnart (S. ooldea) is comparable in many ways, fulfilling a similar ecological niche, but is restricted to a smaller Centralian distribution of exclusively hyper-arid woodlands and tussock grasslands. Where the species co-occur at Lake Mason Station (27.586 ºS, 119.519 ºE) in the eastern Murchison region of Western Australia it appears that S. ooldea were trapped more often in sandplain sites with dense vegetation and high terrestrial invertebrate diversity. Sminthopsis macroura were more trapable in hilly and rocky sites, suggesting that other factors determine their habitat choice. Tentatively it seems that S. ooldea may favour less variable microclimates, and I examine if they may not be so physiologically tolerant as S. macroura. To investigate their basic metabolic physiology, thermoregulatory tolerances and energy requirements, S. macroura and S. ooldea were exposed to acute Tas of 10, 25, 30 and 35 °C and flowthrough respirometry used to measure metabolic rate and evaporative water loss. Sminthopsis macroura is a strong thermoregulator across a broad range of ambient conditions, whereas S. ooldea is thermolabile and does not regulate its body temperature tightly below the thermoneutral zone (TNZ). Therefore, S. macroura has a steeper slope to the metabolic profile as Ta declines, and at any Ta below the TNZ requires more energy per unit of body mass than S. ooldea, and has a higher EWL at the lower critical Ta.

Présentation

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