Torpor in the European white-toothed shrews

Nagel, Anne

doi:10.1007/bf01918804

Cited by 54 publications

(21 citation statements)

References 4 publications

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“…(Geoffroy 1827) was elicited spontaneously in the presence of food (Baxter et al 1979, Frey 1980, Genoud 1985, Baxter 1996. Torpidity has also been reported for free-ranging Crocidura (Nagel 1977, Vogel and Genoud 1981. Myosorex varius (Smuts 1832), a crocidurine trapped in KwaZulu-Natal, South Africa, showed contrasting behavior to most crocidurines, in that M. varius did not enter torpor (Brown et al 1997).…”

Section: Torpiditymentioning

confidence: 90%

Social thermoregulation in least shrews, Cryptotis parva

Merritt

Zegers

2014

Mammalia

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Abstract:Cryptotis parva exhibits a geographic range and ecological requirements unique among North American soricines: it possesses a latitudinal distribution, metabolism and communal nesting pattern more like the crocidurines of the eastern hemisphere. We utilized oxygen consumption (VO 2 ) techniques to examine metabolic shifts and video to document activity patterns and dynamics of solitary and group nesting C. parva. Between ambient temperatures of 4°C and 34°C, solitary C. parva demonstrated an inverse relationship between ambient temperature (T a ) and resting metabolic rate (RMR); thermal neutral zone (TNZ) was very narrow, between a T a of 34°C and 36°C. VO 2 was measured in groups ranging in size from one to eight at T a s of 4°C, 14°C, 24°C and 34°C. The group size had a significant effect on the median RMR and median predicted Kleiber value and was more effective at reducing metabolic cost at a lower T a . In a second experiment designed to assess the effects of huddling group size and incubator T a on the T a of the nest chamber, both had significant effects. Group size had significant effects on the T a of the nest chamber at incubator temperatures of 5°C, 10°C, 15°C and 32°C, but not at 25°C. We found no behavioral or physiologic evidence of heterothermy.

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Section: Torpiditymentioning

confidence: 90%

Social thermoregulation in least shrews, Cryptotis parva

Merritt

Zegers

2014

Mammalia

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“…Even if food is seemingly unlimited, animals eat and digest following a very rhythmic circadian pattern. The smallest endotherms (e.g., hummingbirds and shrews) maintain a near constant assimilation of energy to fuel their exceedingly high metabolic rates, but cease feeding during bouts of torpor (237,330,396). If food becomes limited, feeding is less frequent and may stop.…”

Section: Biology Of Fastingmentioning

confidence: 98%

Integrative Physiology of Fasting

Secor

Carey

2016

Comprehensive Physiology

132

144

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Extended bouts of fasting are ingrained in the ecology of many organisms, characterizing aspects of reproduction, development, hibernation, estivation, migration, and infrequent feeding habits. The challenge of long fasting episodes is the need to maintain physiological homeostasis while relying solely on endogenous resources. To meet that challenge, animals utilize an integrated repertoire of behavioral, physiological, and biochemical responses that reduce metabolic rates, maintain tissue structure and function, and thus enhance survival. We have synthesized in this review the integrative physiological, morphological, and biochemical responses, and their stages, that characterize natural fasting bouts. Underlying the capacity to survive extended fasts are behaviors and mechanisms that reduce metabolic expenditure and shift the dependency to lipid utilization. Hormonal regulation and immune capacity are altered by fasting; hormones that trigger digestion, elevate metabolism, and support immune performance become depressed, whereas hormones that enhance the utilization of endogenous substrates are elevated. The negative energy budget that accompanies fasting leads to the loss of body mass as fat stores are depleted and tissues undergo atrophy (i.e., loss of mass). Absolute rates of body mass loss scale allometrically among vertebrates. Tissues and organs vary in the degree of atrophy and downregulation of function, depending on the degree to which they are used during the fast. Fasting affects the population dynamics and activities of the gut microbiota, an interplay that impacts the host's fasting biology. Fasting-induced gene expression programs underlie the broad spectrum of integrated physiological mechanisms responsible for an animal's ability to survive long episodes of natural fasting.

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“…Thus, the molecular studies are, in a sense, supportive of microchiropteran and megachiropteran diphyly, with Soricidae forming a potential sister group to the microchiropterans. In addition, certain species of shrews and all microchiropterans use echolocation to map their surroundings (Symonds, 2005;Siemers et al, 2009), and species from both groups are known to undergo a process of torpor (Nagal, 1977;Geiser, 2004;Symonds, 2005). Thus, there is substantial preliminary evidence linking the microchiropterans with the Soricidae, providing a potential phylogenetic niche for the microchiropterans in the diphyletic scenario of chiropteran evolution.…”

Section: Insectivores and Microchiropteran Affinitiesmentioning

confidence: 99%

Nuclear organisation of some immunohistochemically identifiable neural systems in five species of insectivore —Crocidura cyanea, Crocidura olivieri, Sylvisorex ollula, Paraechinus aethiopicus and Atelerix frontalis

Calvey

Patzke

Bennett

et al. 2016

Journal of Chemical Neuroanatomy

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Paul.Manger@wits.ac.za 1 Highlights• Several neural systems in the brains of insectivores are described.• All species show a similar global pattern of organization.• Certain variations indicate a phylogenetic relationships between shrews and microchiropterans.• This study support the diphyletic hypothesis of bat evolution. AbstractThe organization of the cholinergic, catecholaminergic, and serotonergic neurons in the brains of five species of insectivores and the orexinergic (hypocretinergic) system in four insectivore species is presented. We aimed to investigate the nuclear complement of these neural systems in comparison to those of other mammalian species. Brains of insectivores were coronally sectioned and immunohistochemically stained with antibodies against cholineacetyltransferase, tyrosine hydroxylase, serotonin and orexin-A. The majority of nuclei were similar among the species investigated and to mammals in general, but certain differences in the nuclear complement highlighted potential phylogenetic interrelationships.In the cholinergic system, the three shrew species lacked parabigeminal and EdingerWestphal nuclei. In addition, the appearance of the laterodorsal tegmental nucleus in all insectivores revealed a mediodorsal arch. All three of these features are the same as those present in microchiropterans. The catecholaminergic system of the three shrew species lacked the A4 and A15d nuclei, as well as having an incipient A9v nucleus, again features found in microchiropteran brains. The serotonergic and orexinergic systems of the insectivores are similar to those seen across most Eutherian mammals. The analysis of similarities and differences across mammalian species indicates a potential phylogenetic relationship between the Soricidae (shrews) and the microchiropterans.

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Torpor in the European white-toothed shrews

Cited by 54 publications

References 4 publications

Social thermoregulation in least shrews, Cryptotis parva

Social thermoregulation in least shrews, Cryptotis parva

Integrative Physiology of Fasting

Nuclear organisation of some immunohistochemically identifiable neural systems in five species of insectivore —Crocidura cyanea, Crocidura olivieri, Sylvisorex ollula, Paraechinus aethiopicus and Atelerix frontalis

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