Effects of cold on activity and exploration by wild house mice in a residential maze

Zoological Journal of the Linnean Society

Warth

1980

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Scrnt marking by deposition of urine, and the preputial glands, of adult, male, wild housr mire, ,\fus , n l l r c 7 l h L., were studied and compared with those of an outbred domestic \train. Thr preputial glands of dominant wild mice were always heavier than those of subordinate\. No dominance relationships could be established among the domestic mice. For study of scent marking each mouse was ohsened singly in a residential maze. Dominant wild mice marked mow than thr suboi-dinates. The domestic inice scent-marked much less even than the subordinate wild micr. Subordinate wild mice spent less time than the dominant wild mice outside the nest; but the numbczr of rxcursions oritside the nest made by the subordinates resembled that of the dominants. Hrncr cocial status inllucnccd the pattern of movements in a structured environment.

Section: Mice and Methodsmentioning

confidence: 99%

Social status, activity and preputial glands of wild and domestic house mice

Zoological Journal of the Linnean Society

Warth

1980

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“…Such adaptation can, however, occur. Wild house mice bred in captivity have been observed in a residential maze: immediately after transfer from warm to cold (3 "C) they visited peripheral parts of the maze less frequently, and spent less time out of the nest, than did cold-adapted mice (Barnett, Hocking & Wolfe, 1978). Even nest-building may be diminished for several days after exposure to cold; but, after 3 0 days in an environment at 3 "C, better nests are rapidly built (Wolfe & Barnett, 1977;cf.…”

Section: V the S T A G E S Of O N T O G E N E T I C Adaptationmentioning

confidence: 99%

Wild Mice in the Cold: Some Findings on Adaptation

1989

Biological Reviews

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The house mouse, Mus domesticus, can thrive in natural environments much below its optimum temperature. Thermogenesis is then above that at more usual temperatures. In addition, body weight, and the weights of brown adipose tissue and the kidneys, may be higher than usual. In free populations of house mice cold lowers fertility and may prevent breeding. Other possible limiting factors on breeding are food supply, shelter for nesting and social interactions. In captivity, wild-type house mice exposed to severe cold (around 0 degrees C) at first adapt ontogenetically by shivering and reduced activity. But raised thermogenesis is soon achieved without shivering; nest-building improves; and readiness to explore may be enhanced. Endocrine changes probably include, at least initially, a rise in adrenal cortical activity and in catecholamine secretion. Some females become barren, but many remain fertile. The maturity of fertile females is, however, delayed and intervals between births are lengthened; nestling mortality rises. A limiting factor during lactation may be the capacity of the gut. Similar adaptive changes are observed during winter in some species of small mammals that do not hibernate. But neither the house mouse nor other species present a single, universal pattern of cold-adaptation. Wild-type mice bred for about 10 generations in a warm laboratory environment (20-23 degrees C) change little over generations. In cold they become progressively heavier and fatter at all ages; they mature earlier, and nestling mortality declines. The milk of such 'Eskimo' females is more concentrated than that of controls. If 'Eskimo' mice are returned to a warm environment, they are more fertile, and rear heavier young, than controls that remained in the warm. Despite the heavier young, litter size is not reduced: it may be increased, probably as a result of a higher ovulation rate. Parental effects have been analyzed by cross-fostering and hybridizing. Survival, growth and fertility are all favourably influenced by the intra-uterine and nest environments provided by 'Eskimo' females. 'Eskimo' males are also better fathers. Hence after ten generations the phenotype of cold-adapted house mice shows the combined effects of (a) an ontogenetic response to cold, (b) a superior parental environment and (c) a change genotype. The secular changes in the cold that lead to this phenotype give the appearance of evolution in miniature; but it is equally possible that they represent a genetical versatility that allows rapid, reversible shifts in response to environmental demands.(ABSTRACT TRUNCATED AT 400 WORDS)

“…The ontogenetic changes in a mouse adapted to cold are primarily; (a) an increase in heat production, and (b) additional nest-building but lower total activity (Barnett, 1965(Barnett, , 1973Barnett, Hocking & Wolfe, 1978;Wolfe & Barnett, 1977). The metabolic change entails alterations in many organs: the heart, kidneys, liver and small intestine of cold-adapted mice are heavier, relative to body weight, than those of mice kept in the warm.…”

Section: Generalities On Cold-adaptationmentioning

confidence: 99%

Changes among wild House mice (Mus musculus) bred for ten generations in a cold environment, and their evolutionary implications

1984

Journal of Zoology

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Wild House mice, Mus musculus, bred at 23°C (controls) changed little in reproductive performance over ten generations. Similar mice bred at 3°C (Eskimo) became more fertile and heavier. Eskimo body fat also rose. Control adrenal weights declined; Eskimo adrenal weights were heavier than those of controls, but only during the first four generations. The Eskimo phenotype after ten generations was a combined result of a direct response to cold, parental effects and genetical changes in the Eskimo population. Maternal effects were probably especially important. In such conditions, the minimum unit of selection that it is useful to consider is the female and her litter.