scholarly journals MATERNAL AGE DRIVES SEASONAL VARIATION IN LITTER SIZE OF PEROMYSCUS LEUCOPUS

10.1644/013 ◽  
2004 ◽  
Vol 85 (5) ◽  
pp. 940-947 ◽  
Author(s):  
M. A. Havelka ◽  
J. S. Millar
Keyword(s):  
Seasonal Variation ◽  
Litter Size ◽  
Maternal Age ◽  
Peromyscus Leucopus

Seasonal Variation in Litter Size of the Meadow Vole in Southern Ontario

1963 ◽  
Vol 44 (4) ◽  
pp. 467 ◽  
Author(s):  
Edward Kott ◽  
William L. Robinson
Keyword(s):  
Seasonal Variation ◽  
Litter Size ◽  
Meadow Vole ◽  
Southern Ontario

Pig melatonin receptor 1a (MTNR1A) genotype is associated with seasonal variation of sow litter size

2009 ◽  
Vol 115 (1-4) ◽  
pp. 317-322 ◽  
Author(s):  
O. Ramírez ◽  
A. Tomàs ◽  
C. Barragan ◽  
J.L. Noguera ◽  
M. Amills ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Litter Size ◽  
Melatonin Receptor

On the Evolution of Litter Size in Peromyscus leucopus

Evolution ◽  
1978 ◽  
Vol 32 (1) ◽  
pp. 45 ◽  
Author(s):  
Theodore H. Fleming ◽  
Robert J. Rauscher
Keyword(s):  
Litter Size ◽  
Peromyscus Leucopus

Spina bifida and anencephaly: a problem in genetic–environmental interaction

1969 ◽  
Vol 1 (1) ◽  
pp. 71-83 ◽  
Author(s):  
C. O. Carter
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Seasonal Variation ◽  
Spina Bifida ◽  
Maternal Age ◽  
Genetic Factors ◽  
Order Effects ◽  
Childhood Morbidity ◽  
The Central Nervous System ◽  
Spina Bifida Cystica

SummaryAnencephaly and spina bifida cystica, malformations of the central nervous system, are due to failure of closure of the neural tube. These malformations are a major cause of stillbirth, infant death and (in the case of spina bifida) of childhood morbidity in Britain today.Their aetiology is not known in detail. There are, however, indications from family studies and from the striking racial variation in their incidence (which is in part at least maintained after migration) that genetic factors are important in their causation. There is also evidence from maternal age and birth order effects, secular and seasonal variation, and social class effects that environmental factors also are important in their aetiology.

Incidence of pup mortality in the rat with particular reference to nesting material, maternal age and parity

1976 ◽  
Vol 10 (2) ◽  
pp. 165-169 ◽  
Author(s):  
M. L. Norris ◽  
C. E. Adams
Keyword(s):  
Litter Size ◽  
Maternal Age ◽  
Nesting Material ◽  
Pup Mortality

Mortality and hence the proportion of young weaned was markedly affected by the type of nesting material but not by maternal age or parity. With paper tissues for nesting purposes 476/791 (60%) young were lost compared with 216/1182 (18%) with woodwool. Similar results were obtained in 2 additional series. The proportion of young weaned was also affected by litter size; in general, pup mortality was heavier and took place earlier in the large litters (more than 9 young).

scholarly journals Seasonal variation in the litter size in relation with variations in the ovulation rate and the embryo mortality in the sow

1981 ◽  
Vol 30 (3) ◽  
pp. 383-383
Author(s):  
Françoise MARTINAT-BOTTE ◽  
P. DANDO ◽  
J. GAUTIER ◽  
M. TERQUI
Keyword(s):  
Seasonal Variation ◽  
Litter Size ◽  
Ovulation Rate ◽  
Embryo Mortality

Modification of Teratogenic Action of Cortisone in Mice by Maternal Age, Maternal Weight and Litter Size

1956 ◽  
Vol 185 (1) ◽  
pp. 65-68 ◽  
Author(s):  
Harold Kalter
Keyword(s):  
Cleft Palate ◽  
Litter Size ◽  
Maternal Age ◽  
Fat Metabolism ◽  
Maternal Weight ◽  
Hybrid Female ◽  
Teratogenic Action ◽  
Median Cleft ◽  
Highly Correlated

Primigravid, hybrid female mice of a range of weights and ages were given injections of 2.5 mg cortisone acetate/day for 4 successive days beginning 11 1/3 days postconception. The frequency of offspring born with median cleft palate decreased with increasing maternal weight, advancing maternal age and increased litter sizes. Analysis of the data by multiple regression has shown that the cleft palate frequency depends on maternal weight, and that maternal age and litter size seem to play a role only because they are so highly correlated with maternal weight. In mice of constant parity, therefore, heavier animals are more resistant to the cleft palate-inducing properties of cortisone than lighter animals are. The possible role of maternal fat metabolism is discussed.

Unexpected seasonal variation in offspring size and performance in a viviparous ectoparasite

Parasitology ◽  
2012 ◽  
Vol 140 (2) ◽  
pp. 229-236 ◽  
Author(s):  
LAURA HÄRKÖNEN ◽  
EIJA HURME ◽  
ARJA KAITALA
Keyword(s):  
Seasonal Variation ◽  
Maternal Age ◽  
Life History Evolution ◽  
Blood Feeding ◽  
Reproductive Period ◽  
Offspring Size ◽  
Offspring Performance ◽  
Young Females ◽  
And Performance ◽  
Deer Ked

SUMMARYOffspring size and performance in invertebrates often decrease with maternal age or as a response to seasonal environment. In viviparous ectoparasites maternal provision may wholly determine offspring performance outside the host. The viviparous deer ked (Lipoptena cervi), an ectoparasite of cervids, breeds from autumn to spring. We reared deer ked pupae through the reproductive period to investigate whether offspring size and performance vary according to maternal age and offspring environment. We expected that, in autumn, young females would produce the largest offspring to ensure that early-born pupae would survive a long period of winter diapause, and that offspring size would decrease with maternal age and decreasing diapause length. Diapause was associated with a significant weight loss, which reduced survival through post-diapause development. It was thus surprising that the early-born offspring were the smallest, and that size and survival (eventually) increased towards the spring. The variability among offspring in the length of off-host period seems to be an important component of life-history evolution in this ectoparasite, and should be studied further. Unexpected seasonal variation in the offspring size of this blood-feeding ectoparasite may result from changes in female resources due to weakening host condition as the winter progresses.

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