Winter survival in northern Peromyscus maniculatus

1993 ◽  
Vol 71 (1) ◽  
pp. 125-129 ◽  
Author(s):  
John S. Millar ◽  
Taye Teferi
Keyword(s):  
Body Size ◽  
Population Density ◽  
Peromyscus Maniculatus ◽  
Resource Competition ◽  
Winter Survival ◽  
Winter Mortality ◽  
Low Resource ◽  
Residency Status ◽  
Young Of The Year ◽  
Old Mice

Winter survival of Peromyscus maniculatus in the Kananaskis Valley, Alberta, was examined in relation to sex, age, population density, size of family groups, body size, and residency status to determine the factors responsible for low winter mortality in northern populations. Young-of-the-year mice survived much better (≈ 50%) than old (> 1 year old) mice (≈ 25%) but no other factor had a significant effect on survival. We conclude that low resource competition may enhance winter survival in northern populations.

Relocation of nest sites by female deer mice, Peromyscus maniculatus borealis

1990 ◽  
Vol 68 (11) ◽  
pp. 2364-2367 ◽  
Author(s):  
Sean T. Sharpe ◽  
J. S. Millar
Keyword(s):  
Population Density ◽  
Predator Avoidance ◽  
Peromyscus Maniculatus ◽  
Nest Site ◽  
Deer Mice ◽  
Early Lactation ◽  
Nest Sites ◽  
Significant Difference ◽  
Breeding Condition ◽  
Young Of The Year

Nest-sites of female Peromyscus maniculatus borealis were monitored during 1985 and 1986 in the Kananaskis Valley, Alberta, Canada. Nest-site relocation by breeding overwintered adults and young of the year was common. There was no significant difference in the distance moved between years and sites or among reproductive-status groups. Nest relocations were most common in 1985, when population density was approximately half that in 1986. There were no differences in the numbers of relocations per season due to site or age. Females in breeding condition moved 3 times more frequently than did nonbreeders, which were young of the year. Relocations were most frequent at parturition and during early lactation, and thus may serve as a predator-avoidance mechanism. Some relocations by females may have served to leave former nest sites to offspring from previous litters.

An ecological explanation for hyperallometric scaling of reproduction

2021 ◽  
Author(s):  
Tomos Potter ◽  
Anja Felmy
Keyword(s):  
Body Size ◽  
Reproductive Output ◽  
Resource Competition ◽  
Natural Populations ◽  
Scaling Exponent ◽  
Wild Populations ◽  
Wet Season ◽  
Size Dependent ◽  
In The Wild ◽  
The Relationship

AbstractIn wild populations, large individuals have disproportionately higher reproductive output than smaller individuals. We suggest an ecological explanation for this observation: asymmetry within populations in rates of resource assimilation, where greater assimilation causes both increased reproduction and body size. We assessed how the relationship between size and reproduction differs between wild and lab-reared Trinidadian guppies. We show that (i) reproduction increased disproportionately with body size in the wild but not in the lab, where effects of resource competition were eliminated; (ii) in the wild, the scaling exponent was greatest during the wet season, when resource competition is strongest; and (iii) detection of hyperallometric scaling of reproduction is inevitable if individual differences in assimilation are ignored. We propose that variation among individuals in assimilation – caused by size-dependent resource competition, niche expansion, and chance – can explain patterns of hyperallometric scaling of reproduction in natural populations.

scholarly journals Recruitment sex ratios in gray-tailed voles (Microtus canicaudus) in response to density, sex ratio, and season

2003 ◽  
Vol 81 (8) ◽  
pp. 1306-1311 ◽  
Author(s):  
Monica L Bond ◽  
Jerry O Wolff ◽  
Sven Krackow
Keyword(s):  
Population Density ◽  
Sex Ratio ◽  
Resource Competition ◽  
Sex Ratios ◽  
Female Offspring ◽  
High Population ◽  
Reproductive Value ◽  
High Population Density ◽  
Adult Sex Ratio ◽  
Sex Ratio Adjustment

We tested predictions associated with three widely used hypotheses for facultative sex-ratio adjustment of vertebrates using eight enclosed populations of gray-tailed voles, Microtus canicaudus. These were (i) the population sex ratio hypothesis, which predicts that recruitment sex ratios should oppose adult sex-ratio skews, (ii) the local resource competition hypothesis, which predicts female-biased recruitment at low adult population density and male-biased recruitment at high population density, and (iii) the first cohort advantage hypothesis, which predicts that recruitment sex ratios should be female biased in the spring and male biased in the autumn. We monitored naturally increasing population densities with approximately equal adult sex ratios through the spring and summer and manipulated adult sex ratios in the autumn and measured subsequent sex ratios of recruits. We did not observe any significant sex-ratio adjustment in response to adult sex ratio or high population density; we did detect an influence of time within the breeding season, with more female offspring observed in the spring and more male offspring observed in the autumn. Significant seasonal increases in recruitment sex ratios indicate the capacity of female gray-tailed voles to manipulate their offspring sex ratios and suggest seasonal variation in the relative reproductive value of male and female offspring to be a regular phenomenon.

QUANTIFYING NATURAL SELECTION ON BODY SIZE FROM FIELD DATA: WINTER MORTALITY IN MENIDIA MENIDIA

Ecology ◽  
2003 ◽  
Vol 84 (8) ◽  
pp. 2168-2177 ◽  
Author(s):  
Stephan B. Munch ◽  
Marc Mangel ◽  
David O. Conover
Keyword(s):  
Body Size ◽  
Natural Selection ◽  
Field Data ◽  
Winter Mortality ◽  
Menidia Menidia

scholarly journals Mesenchymal Stem Cell-Specific and Preosteoblast-Specific Ablation of TSC1 in Mice Lead to Severe and Slight Spinal Dysplasia, Respectively

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Cheng Yang ◽  
Jianwen Liao ◽  
Pinglin Lai ◽  
Hai Huang ◽  
Shicai Fan ◽  
...  
Keyword(s):  
Stem Cell ◽  
Body Size ◽  
Mesenchymal Stem Cell ◽  
Endochondral Ossification ◽  
Intervertebral Discs ◽  
Tsc1 Gene ◽  
Spine Development ◽  
Old Mice ◽  
Deficient Mice ◽  
Specific Deletion

Background. TSC1-related signaling plays a pivotal role in intramembranous and endochondral ossification processes during skeletogenesis. This study was aimed at determining the significance of the TSC1 gene at different stages of spinal development. Materials and Methods. TSC1-floxed mice (TSC1flox/flox) were crossed with Prrx1-Cre or BGLAP-Cre transgenic mice or mesenchymal stem cell- and osteoblast-specific TSC1-deficient mice, respectively. Somatic and vertebral differences between WT and Prrx1-TSC1 null mice were examined at 4 weeks after birth. Results. No apparent body size abnormalities were apparent in newborn and 4-week- to 2-month-old mice with BGLAP-Cre driver-depleted TSC1. Vertebral and intervertebral discs displayed strong dysplasia in Prrx1-TSC1 null mice. In contrast, vertebrae were only slightly affected, and intervertebral discs from skeletal preparations displayed no apparent changes in BGLAP-TSC1 null mice. Conclusion. Our data suggest that the TSC1 gene is crucial for endochondral ossification during postnatal spine development but plays discriminative roles at different stages. Mesenchymal stem cell-specific ablation of TSC1 led to severe spinal dysplasia at early stages of endochondral ossification while osteoblast-specific deletion of TSC1 affected vertebrae slightly and had no detectable effects on intervertebral discs.

Effects of population density on female and male burrow characteristics in the fiddler crab, Uca bengali Crane, 1975

Crustaceana ◽  
2015 ◽  
Vol 88 (12-14) ◽  
pp. 1283-1299 ◽  
Author(s):  
Fahmida Wazed Tina ◽  
Mullica Jaroensutasinee ◽  
Krisanadej Jaroensutasinee
Keyword(s):  
Body Size ◽  
Population Density ◽  
Fiddler Crab ◽  
High Density ◽  
The Other ◽  
Low Density ◽  
Density Effects ◽  
Egg Incubation ◽  
Other Hand ◽  
Males And Females

We examined the effects of population density on body size and burrow characteristics ofUca bengaliCrane, 1975. We predicted that (1) males in high-density areas (HD) should be larger in size and build higher quality burrows than males in low-density areas (LD), and (2) HD females should be larger in size, but build lower quality burrows than LD females, as HD females can find higher numbers of good quality male burrows around them for breeding and egg incubation. Our results showed that males and females in HD were larger in size than those in LD. Since HD males were larger in size, they built higher quality burrows than males in LD. On the other hand, even though LD females were smaller in size than HD ones, they built higher quality burrows than HD females. Our results thus indicate that density effects both body size and burrow characteristics.

scholarly journals Winter mortality, development and reproduction in a field population of Myzus persicae (Sulzer) (Hemiptera: Aphididae) in England

1984 ◽  
Vol 74 (4) ◽  
pp. 633-640 ◽  
Author(s):  
R. Harrington ◽  
Cheng Xia-Nian
Keyword(s):  
Myzus Persicae ◽  
Growth And Development ◽  
Population Change ◽  
Leaf Surface ◽  
Winter Survival ◽  
Winter Mortality ◽  
Biological Factors ◽  
Surface Wetness ◽  
South Eastern ◽  
The Relationship

AbstractPopulation change in Myzus persicae (Sulz.) overwintering on spring cabbage in south-eastern England was studied in relation to meteorological and biological factors. Leaf surface wetness and temperature were correlated significantly with rate of population change, but rainfall and wind were not. Growth and development continued slowly throughout the winter, and the relationship with temperature is shown. Hymenopterous parasites, the fungus Entomophthora and predatory spiders did not affect winter survival.

Effects of temperature and salinity on survival of young-of-the-year Hudson River striped bass (Morone saxatilis): implications for optimal overwintering habitats

2002 ◽  
Vol 59 (5) ◽  
pp. 787-795 ◽  
Author(s):  
Thomas P Hurst ◽  
David O Conover
Keyword(s):  
Body Size ◽  
Low Temperature ◽  
Striped Bass ◽  
Low Temperatures ◽  
Morone Saxatilis ◽  
Hudson River ◽  
Temperature Tolerance ◽  
Low Temperature Tolerance ◽  
Energetic State ◽  
Young Of The Year

We examined the role of salinity, body size, and energetic state in determining low temperature tolerance of young-of-the-year (YOY) striped bass (Morone saxatilis) and used this information to map optimal overwintering habitat in the Hudson River estuary. A long-term experiment compared survival at 15 ppt and 30 ppt. In additional experiments, winter-acclimated fish were exposed to temperature declines (2.3°C·day–1 to 1°C·week–1) at salinities from 0 ppt to 35 ppt. Highest survival at low temperatures was consistently observed at intermediate salinities. These results suggest that the observed distribution of overwintering striped bass is related to physiological constraints on osmo regulatory ability at low temperatures. Low temperature tolerance appeared unrelated to body size and energetic state. Salinity profiles were used to describe the location and extent of optimal wintering habitats under various hydrographic regimes. The location of optimal habitats was displaced by over 27 km along the river axis because of variation in salinity regime. Changes in the availability of optimal habitat may be responsible for variation in recruitment to the Hudson River population. These results demonstrate the need to consider a holistic approach encompassing all seasons of the year in assessing habitat requirements of fishes.

POPULATION DENSITY AND SEX RATIO DYNAMICS OF OVERWINTERING MAIZE WEEVILS (COLEOPTERA: CURCULIONIDAE) INFESTING FIELD CORN

1986 ◽  
Vol 21 (4) ◽  
pp. 368-375 ◽  
Author(s):  
D. E. Dix ◽  
J. N. All
Keyword(s):  
Population Density ◽  
Sex Ratio ◽  
Cold Tolerance ◽  
Sitophilus Zeamais ◽  
Winter Mortality ◽  
Weather Extremes ◽  
Maize Weevil ◽  
Monthly Basis ◽  
Field Corn ◽  
Cold Hardy

Natural infestations of the maize weevil, Sitophilus zeamais (Motschulsky) were monitored in selected corn fields located in each of five major climatic or edaphic environments of Georgia. The population density and sex ratio of each population was recorded on a monthly basis during the fall and winters of 1982–83–84. Females suffered higher winter mortality than males, resulting in increasingly male-skewed sex ratios (from 0.8/1.0 to 1.6/1.0) as winter progressed. The degree of male-skewedness was positively correlated with the amount of subzero weather experienced by each population. Surviving weevil populations decreased in size as winter progressed, with the greatest reductions at the higher latitudes. No weevils survived through spring north of 33° 57′N where winter weather extremes of −15°C occurred. No true diapausing stage was found; however, cold tolerance tests indicated that winter-collected weevils were significantly more cold hardy than laboratory-reared weevils.

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