Dear John Speakman,
نویسنده
چکیده
Several lines of evidence indicate that animals in the wild may be limited in their maximal rates of energy intake by their intrinsic physiology rather than food availability. Understanding the limits to sustained energy intake is important because this defines an envelope within which animals must trade-off competing activities. In the first part of this review, we consider the initial ideas that propelled this area and experimental evidence connected with them. An early conceptual advance in this field was the idea that energy intake could be centrally limited by aspects of the digestive process, or peripherally limited at the sites of energy utilisation. A model system that has been widely employed to explore these ideas is lactation in small rodents. Initial studies in the late 1980s indicated that energy intake might be centrally limited, but work by Hammond and colleagues in the 1990s suggested that it was more likely that the limits were imposed by capacity of the mammary glands, and other works tended to support this view. This consensus, however, was undermined by studies that showed milk production was higher in mice at low temperatures, suggesting that the capacity of the mammary gland is not a limiting factor. In the second part of the review we consider some additional hypotheses that might explain these conflicting data. These include the heat dissipation limits hypothesis, the seasonal investment hypothesis and the saturated neural control hypothesis. Current evidence with respect to these hypotheses is also reviewed. The limited evidence presently available does not unambiguously support any one of them.
منابع مشابه
The energetic and oxidative costs of reproduction in a freeranging rodent
Patrick Bergeron*, Vincent Careau, Murray M. Humphries, Denis Réale, John R. Speakman and Dany Garant Département de Biologie, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada; Department of Biology, University of California, Riverside, California 92521, USA; Natural Resource Sciences, McGill University, Macdonald Campus, Québec H9X 3V9, Canada; Département des Sciences Biologiques,...
متن کاملResting and daily energy expenditures during reproduction are adjusted in opposite directions in freeliving birds
reproduction are adjusted in opposite directions in free-living birds Jorg Welcker*, John R. Speakman, Kyle H. Elliott, Scott A. Hatch and Alexander S. Kitaysky Norwegian Polar Institute, Fram Centre, N-9296 Tromsø, Norway; Institute of Arctic Biology, University of Alaska Fairbanks, Irving 311, Fairbanks, Alaska 99775 USA; Institute of Biological and Environmental Sciences, University of Aberd...
متن کاملDaily energy expenditure increases in response to low nutritional stress in an Arctic-breeding seabird with no effect on mortality
Jorg Welcker*, Ann M. A. Harding, Alexander S. Kitaysky, John R. Speakman and Geir W. Gabrielsen Norwegian Polar Institute, Polarmiljøsenteret, 9296 Tromsø, Norway; Department of Biology, University of Tromsø, 9037 Tromsø, Norway; Alaska Pacific University, Environmental Science Department, 4101 University Drive, Anchorage, AK 99508, USA; Institute of Integrative and Comparative Biology, Univer...
متن کاملDaily energy expenditure during lactation is strongly selected in a freeliving mammal
selected in a free-living mammal Quinn E. Fletcher*, John R. Speakman, Stan Boutin, Jeffrey E. Lane, Andrew G. McAdam, Jamieson C. Gorrell, David W. Coltman and Murray M. Humphries Department of Natural Resource Sciences, Macdonald Campus, McGill University, Ste-Anne-de-Bellevue, Quebec H9X 3V9, Canada; Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen,AB24 2T...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2005