Daylength influences pelage and plasma prolactin concentrations but not reproduction in the prairie vole, Microtus ochrogaster

Smale, Laura; Nelson, Randy J.; Zucker, Irving H.

doi:10.1530/jrf.0.0830099

Cited by 38 publications

(16 citation statements)

References 19 publications

(18 reference statements)

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“…Small body size, with its associated short life span, is unlikely to favor photoperiodic inhibition of reproduction unless the inhibition promotes survival, for example, during a harsh winter [36]. It has therefore been suggested that the evolutionary pressure favoring reproductive photoresponsiveness will decrease with decreasing latitude and body size, and that small mammals below 30°of latitude may cease to use photoperiod as a proximate cue and become opportunistic [3,9,16,36,37]. This is supported by the limited available data, which show that below 10°of latitude, neither seasonally nor aseasonally breeding mammals respond to changes in day length [9][10][11][12].…”

Section: Discussionmentioning

confidence: 99%

Failure of the Estrous Cycle and Spermatogenesis to Respond to Day Length in a Subtropical African Rodent, the Pouched Mouse (Saccostomus Campestris)1

Bernard

Hall²

1995

Biology of Reproduction

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Little is known about the role of photoperiod in the control of reproduction in mammals from the tropics in general and, in particular, from the Afrotropics. The present study examined the reproductive photosensitivity of the pouched mouse (Saccostomus campestris: Cricetidae), a small, seasonally breeding rodent that occurs from about 12 degrees S to 33 degrees S in Africa. Groups of 10 laboratory-bred male pouched mice were exposed to either long-day (16L:8D) or short-day (8L:16D) conditions for 14 wk, after which they were killed and the spermatogenic activity of the testes was assessed histologically. A group of 10 adult, multiparous females were exposed to long-day conditions for 3 mo, after which the lengths of five consecutive estrous cycles were measured. Thereafter, day length was reduced to 10L:14D, and after 16 days acclimation, the lengths of five estrous cycles were measured. Finally, day length was reduced to 8L:16D, and after 33 days, the lengths of five estrous cycles were measured. Day length had no influence on body size, testis size, or the histology of the testis, and all specimens were actively producing spermatozoa. The length of the estrous cycle (4.0 +/- 0.3 days under long-day conditions) did not change significantly with the decrease in photoperiod. In a third experiment, 14 multiparous and six nulliparous females that had been maintained under short-day conditions for 33 days were mated and successfully reared litters.(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Discussionmentioning

confidence: 99%

Failure of the Estrous Cycle and Spermatogenesis to Respond to Day Length in a Subtropical African Rodent, the Pouched Mouse (Saccostomus Campestris)1

Bernard

Hall²

1995

Biology of Reproduction

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“…In Djungarian hamsters, weasels, lemmings and voles, exposure to short photoperiods induces molt to the winter pelage and exposure to long photoperiods induces molt to the summer pelage *Member, Academia Brasileira de Ciências Correspondence to: A.M.L. Castrucci E-mail: amdlcast@ib.usp.br (Duncan et al 1985, Rust and Meyer 1969, Smale et al 1988). Minks and squirrels present an endogenous rhythm of molt which is strongly influenced by changes in photoperiod (Martinet et al 1992) or temperature (Joy and Mrosovsky 1985).…”

Section: Introductionmentioning

confidence: 99%

Seasonal pelage color change: news based on a South American Rodent

Camargo

Colares

Castrucci

2006

An. Acad. Bras. Ciênc.

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Mammalian seasonalmolting and color change are known to be influenced by photoperiod changes. Calomys laucha, a South American rodent, exhibits seasonal pelage color change; however, unlike Northern hemisphere rodents, which present a gray or brown color during summer and a whitish color during winter, C. laucha pelage changes from an orange color during summer to a dark gray color during winter. Animals maintained for over a year in stationary photoperiod (LD 12:12h, 22 • C) presented orange pelage color during the summer corresponding month (January), and gray color during the winter corresponding month (July). Same age animals were evaluated during summer or winter months, and also showed different colors. Animals exposed for 12 weeks to summer or winter artificial conditions displayed color change, not according to the environmental conditions, as expected, but similar to that of animals maintained in stationary photoperiod. These results suggest that pelage color change in C. laucha is controlled by an endogenous circannual rhythm. The adaptive function of C. laucha color change is discussed.

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“…Some species fail to show a reproductive response to photoperiod, yet exhibit other seasonal responses (such as pelage change) that are under photoperiodic regulation (Smale et al 1988;Duncan et al 1985).…”

Section: Introductionmentioning

confidence: 99%

The influence of photoperiod on the reproductive physiology of the greater red musk shrew (Crociduraflavescens)

et al. 2016

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Photoperiodism involves the use of both absolute measures of day length and the direction in which day length is changing as a cue for regulating seasonal changes in physiology and behaviour so that birth and lactation coincide with optimal resource availability, increasing offspring survival. Induced ovulation and opportunistic breeding is often found in species that are predominantly solitary and territorial. In this study, the photoperiodic reproductive responses of male greater red musk shrews (Crocidura flavescens (I. Geoffroy Saint-Hilaire, 1827)) were investigated in the laboratory. The presence of spermatozoa regardless of the light cycle, suggest that although the shrews are photoresponsive, they may be capable of breeding throughout the year. Significantly greater testicular volume and seminiferous tubule diameter following exposure to a short day-light cycle suggests that these animals may have breeding peaks that correspond to short days. The presence of epidermal spines on the penis indicates that the shrew is likely also an induced ovulator.Flexible breeding patterns combined with induced ovulation affords this solitary species the greatest chance of reproductive success. ___________________________________________________________________

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Daylength influences pelage and plasma prolactin concentrations but not reproduction in the prairie vole, Microtus ochrogaster

Cited by 38 publications

References 19 publications

Failure of the Estrous Cycle and Spermatogenesis to Respond to Day Length in a Subtropical African Rodent, the Pouched Mouse (Saccostomus Campestris)1

Failure of the Estrous Cycle and Spermatogenesis to Respond to Day Length in a Subtropical African Rodent, the Pouched Mouse (Saccostomus Campestris)1

Seasonal pelage color change: news based on a South American Rodent

The influence of photoperiod on the reproductive physiology of the greater red musk shrew (Crociduraflavescens)

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