|
|
Eldershaw TP, Duchamp C, Ye J, Clark MG, Colquhoun EQ. (1997). Potential for nonshivering thermogenesis in perfused chicken (Gallus domesticus) muscle. Comp. Biochem. Physiol., Part A Mol. Integr. Physiol., 117A(4), 545–554.
Abstract: The humoral modulation of resting muscle heat production of chickens (Gallus
domesticus) was investigated in vitro. The resting distal lower limb was perfused
via the popliteal artery at 25 degrees C without erythrocytes at constant flow.
The preparation was stable for at least 3 hr, showing a constant oxygen uptake
(MO2) and perfusion pressure as well as adequately maintaining muscle energy
charge and creatine phosphate: creatine ratio. Noradrenaline (NOR), adrenaline
(ADR) and serotonin (5-HT) each caused a dose-dependent rise in perfusion
pressure. NOR and ADR evoked increased MO2 at low doses eventually followed by
decreased MO2 at higher agonist concentrations. 5-HT gave smaller but
qualitatively similar MO2 effects. The actions of 50 nM NOR were blocked by
prazosin (10 microM) and nitroprusside (0.5 mM), but not altered by propranolol
(10 microM). NOR-induced stimulatory MO2 changes in the presence of
pharmacological concentrations (1 microM) of glucagon were more pronounced and
the thermogenic concentration range of NOR was increased. Taken together, these
in vitro findings demonstrate a potential for vasoconstrictor-controlled muscle
nonshivering thermogenesis in birds as in marsupials and mammals, suggesting that
vascular control of muscle MO2 may be a widespread biological mechanism. The
possible implications of these findings for avian nonshivering thermogenesis are
discussed.
Programme: 131
|
|
|
|
Stenni B., Serra F., Frezzotti M., Maggi V., Traversi R., Becagli S. & Udisti R. (2000). Snow accumulation rates in Northern Victoria Land (Antactica) by firn core analysis. Journal of glaciology, 46(155), 541–552.
|
|
|
|
Saintenoy A.C. & Tarantola A. (2001). Ground-penetrating radar: Analysis of point diffractors for modeling and inversion. Geophysics, 66(2), 540–550.
|
|
|
|
Boulinier, T., McCoy, K.D., Yoccoz, N.G., Gasparini, J. & Tveraa, T. (2008). Public information affects breeding dispersal in a colonial bird: kittiwakes cue on neighbours. Biol. Lett., 4, 538–540.
|
|
|
|
Van De Vijver B., Denys L. & Beyens L. (2000). Fragilaria husvikensis sp. nov. (Bacillariophyceae), another Fragilaria species with transapical ribs from Subantarctica. Nova Hedwigia, , 537–550.
|
|
|
|
Mardon, J Bonadonna, F. (2009). Atypical homing or self-odour avoidance? Blue petrels ( Halobaena caerulea ) are attracted to their mate’s odour but avoid their own. Behav. Ecol. Sociobiol. (Print), 63, 537–542.
Abstract: Among procellariiform seabirds, many burrowing petrels show good olfactory abilities especially in recognising their nest. In particular, it has been reported that Antarctic prions (Pachyptila desolata) discriminate their own and their mate’s odours and, in Y-maze experiments, prefer the odour of a conspecific bird to their own. While traditionally examined from the perspective of homing mechanisms, these recent results have drawn attention to the possible use of chemical signals in birds’ social behaviours. Indeed, the life history of petrels suggests that a mate choice mediated by olfactory mechanisms may have evolved in this group to ensure genetic compatibility. This study was undertaken to validate and extend results obtained on petrels’ olfactory discrimination capabilities. Following the Y-maze experiment protocol, blue petrels (Halobaena caerulea) were offered three different choices: (1) mate versus conspecific’s odour, (2) own versus mate’s odour and (3) own versus conspecific’s odour. We discovered that birds prefer the odour of their mate not only when presented against conspecific’s odour but also against their own. We further verified that blue petrels also avoid their own odour when presented against conspecific’s odour. Our results confirm that olfactory discrimination in burrowing petrels goes beyond selfrecognition and that self-odour avoidance may be widespread. We use two mutually non-exclusive behavioural frameworks for the interpretation of our results, homing and mate choice, and explain why homing mechanisms cannot account for all of our observations. This study opens the door to further research on olfactory mechanisms that, in petrels, might mediate individual recognition and mate choice.
Programme: 354
|
|
|
|
Duchamp C., Cohen Adad F., Rouanet J.L., Dumonteil E. & Barre H. (1993). Existence of nonshivering thermogenesis in birds. Life in the Cold:Ecological,Physiological,and Molecular Mechanis, , 529–533.
|
|
|
|
Gay M., Fily M., Genthon C., Frezzotti M., Oerter H. & Winther J.G. (2002). Snow grain-size measurements in Antarctica. Journal of glaciology, 48(163), 527–535.
|
|
|
|
Le Bohec C., Gauthier-Clerc M. & Le Maho Y. (2005). The adaptive significance of crèches in the king penguin. Animal behaviour, 70(3), 527–538.
Abstract: Crèching behaviour in penguins is defined as the rearing of chicks by their own parents in large flocks called 'crèches'. Although several hypotheses have been proposed to account for the behaviour, the factors inducing chicks to aggregate remain relatively poorly understood, in particular for colonial seabirds. We studied crèching behaviour in the king penguin, Aptenodytes patagonicus, by looking at the dynamics of crèche formation and possible costs and benefits associated with this strategy. Crèches increased in size but declined in number throughout the austral winter. They were located preferentially in the central parts of the colony. Lone chicks suffered the most aggression from unrelated adults, whereas chicks in a crèche suffered the least. Chicks attacked by unrelated adults preferentially joined a crèche. Adult aggression appeared to be a major factor inducing crèching behaviour. Chicks at the periphery of a crèche were more vigilant while sleeping, as measured by eye openings. Crèches seemed to occasion intense competition among chicks for access to the centre. Chicks in poor condition were attacked and pushed to the periphery of the crèche, where they were preyed on by giant petrels. During harsh weather conditions, chicks amalgamated into larger crèches, tolerated lower interindividual distances and turned their backs to the wind and rain. Our results accord with the idea that crèching behaviour in king penguins is a strategy that protects chicks from adult aggression, predation and severe weather.
Programme: 137
|
|
|
|
Van Roozendael M., Peeters P., Simon P.C., Roscoe H.K., Jones A., Bartlett L., Vaughan G. & Goutail Pommereau Kyro Walhstrom Braaathen. (1996). Absolute calibration of SAOZ measurements of ozone by comparison with Dodson and Brewer instruments. Bachelor's thesis, , .
Abstract: Proc. Third European Symp. on Polar Ozone
Programme: 209
|
|
