Similarities between female meadow voles mating during post-partum oestrus and raising two concurrent litters and females raising only one litter

2006 ◽  
Vol 18 (7) ◽  
pp. 751 ◽  
Author(s):  
Javier delBarco-Trillo ◽  
Michael H. Ferkin
Keyword(s):  
Sex Ratio ◽  
Maternal Care ◽  
Post Partum ◽  
Microtus Pennsylvanicus ◽  
Meadow Vole ◽  
Gestation Length ◽  
Meadow Voles ◽  
Litter Weight ◽  
In The Wild ◽  
Males And Females

In many species of small mammals, females undergo post-partum oestrus soon after delivering a litter, becoming pregnant while suckling the previous litter. Females raising two concurrent litters need to allocate many more resources to reproduction than females raising only one litter. Consequently, there may be differences between litters raised concurrently or singly. We investigated this issue in the meadow vole, Microtus pennsylvanicus, a species in which most females in the wild reproduce during post-partum oestrus. Specifically, we tested the hypothesis that the development of pups in two concurrent litters differs from that of pups in a single litter. To test this hypothesis, we measured the following variables for concurrent and singly reared litters: gestation length; litter size; sex ratio; bodyweight of males and females at different ages; total litter weight at weaning; growth rates; and intra-litter variation in body mass. Except for bodyweight of males at 60 days of age, which was higher in the first of the concurrent litters, none of the variables differed among the litters. These results indicate that females are able to adjust to differing loads of maternal care to provide equivalent resources to concurrent litters and singly reared litters.

Winter coexistence of voles in spruce forest: relevance of seasonal changes in aggression

1975 ◽  
Vol 53 (8) ◽  
pp. 1004-1011 ◽  
Author(s):  
Brian N. Turner ◽  
Michael R. Perrin ◽  
Stuart L. Iverson
Keyword(s):  
Microtus Pennsylvanicus ◽  
Meadow Vole ◽  
Breeding Period ◽  
Spruce Forest ◽  
Vole Population ◽  
Reproductive Condition ◽  
Interspecific Aggression ◽  
Meadow Voles ◽  
Nonbreeding Season ◽  
Short Period

Beginning in November 1973, numerous meadow voles (Microtus pennsylvanicus) moved onto a spruce forest grid occupied by red-backed voles (Clethrionomys gapperi). A resident meadow vole population resulted, the two species coexisting until April 1974, when most meadow voles disappeared from the grid during a relatively short period. Interspecific aggression levels, as determined from voles temporarily removed from the populations and tested in paired encounters in a laboratory arena, were low during the winter, but increased when males of both species entered reproductive condition in the spring. Microtus was generally dominant in early breeding period encounters, but this dominance declined concurrently with the meadow voles' disappearance from the forest. It is argued that meadow voles did not leave the forest to breed, or because the snow cover melted, since this species will live and reproduce in forest in the absence of Clethrionomys. The results are interpreted as support for an earlier hypothesis that competitive habitat exclusion varies seasonally with reproduction-related aggression. Thus, these species apparently may coexist in either of their preferred habitats when interspecific aggression is low (the nonbreeding season), but this relationship terminates when interspecific aggression levels increase with the resumption of breeding in the spring.

Reduced cannibalism during male pregnancy

Behaviour ◽  
2016 ◽  
Vol 153 (1) ◽  
pp. 91-106 ◽  
Author(s):  
M. Cunha ◽  
A. Berglund ◽  
T. Alves ◽  
N.M. Monteiro
Keyword(s):  
Post Partum ◽  
Feeding Activity ◽  
Filial Cannibalism ◽  
Fitness Costs ◽  
Life History Stages ◽  
In The Wild ◽  
Males And Females ◽  
Male Pregnancy ◽  
Time And Energy ◽  
Benefits And Costs

Cannibalism provides energetic benefits but is also potentially costly, especially when directed towards kin. Since fitness costs increase with time and energy invested in offspring, cannibalism should be infrequent when parental investment is high. Thus, filial cannibalism in male syngnathids, a group known for the occurrence of male pregnancy, should be rare. Using the pipefish (Syngnathus abaster) we aimed to investigate whether cannibalism does occur in both sexes and how it is affected by reproductive and nutritional states. Although rare, we witnessed cannibalism both in the wild and in the laboratory. Unlike non-pregnant males and females, pregnant and post-partum males largely refrained from cannibalising juveniles. Reproducing males decreased their feeding activity, thus rendering cannibalism, towards kin or non-kin, less likely to occur. However, if not continuously fed, all pipefish adopted a cannibal strategy, revealing that sex and life history stages influenced the ratio between the benefits and costs of cannibalism.

Réponse numérique de l'hermine aux fluctuations d'abondance de Microtus pennsylvanicus

1982 ◽  
Vol 60 (4) ◽  
pp. 542-549 ◽  
Author(s):  
Michel Raymond ◽  
Jean-Marie Bergeron
Keyword(s):  
Local Population ◽  
Microtus Pennsylvanicus ◽  
Density Fluctuations ◽  
Numerical Response ◽  
Meadow Vole ◽  
Strongly Correlated ◽  
Vole Population ◽  
Rodent Population ◽  
Males And Females ◽  
Different Response

The numerical response of two ermine populations (Mustela erminea) to the density fluctuations of the meadow vole (Microtus pennsylvanicus), the dominant mammal in southern Quebec agrosystems, was studied from 1978 to 1980. There is a strong correlation between the densities of the two species, whether or not the fluctuations of Microtus are cyclical. Males and females show a different response, the numerical adjustment of males being strongly correlated to the fluctuations of the vole population while the females do not seem to make particular adjustments. The numerical response of the ermine takes place only a few months after the changes in the rodent population. It is suggested that in areas where preys are small and of similar size the survival of the females is less dependent than that of the males on the density of the dominant prey. As most female ermines seem to participate in reproduction whatever the density of the vole population, the continuity of any local population is insured from year to year by the presence of at least minimal numbers. Survival of the young during the year following their birth seems to depend on the immediate availability of prey, thus determining the characteristics of the numerical response.[Journal translation]

Control of Small Mammals on a Hardwood Plantation by Poison-Bait Feeders

1977 ◽  
Vol 53 (2) ◽  
pp. 96-99
Author(s):  
Arthur M. Martell ◽  
Andrew Radvanyi
Keyword(s):  
Small Mammals ◽  
Microtus Pennsylvanicus ◽  
Meadow Vole ◽  
Low Density ◽  
Meadow Voles ◽  
Southern Ontario

Poison-bait feeder stations were placed on a hardwood plantation in southern Ontario in 1973 to attempt long-term control of a meadow vole (Microtus pennsylvanicus) population by continuous dispensing of poisoned grain. Baiting by means of feeders successfully reduced the numbers of meadow voles and maintained them at a low density, about 3-6/ha (1.2-2.4/acre), through April 1976. During the same period, the density of meadow voles on surrounding unpoisoned areas declined from a 1973 peak to about the same as that found on the poisoned plot by fall and winter 1975-76. Despite that low density, less than 4/ha (1.6/acre), severe gnawing and girdling of young hardwoods occurred during winter. Poison-bait feeders are efficient at reducing meadow vole populations from high to low density, but it cannot be assumed that even those low-density populations will not damage hardwood plantations.

Eléments minéraux du régime alimentaire du campagnol des champs, Microtus pennsylvanicus (Ord.)

1976 ◽  
Vol 54 (9) ◽  
pp. 1565-1570 ◽  
Author(s):  
Jean-Marie Bergeron
Keyword(s):  
Stomach Contents ◽  
Microtus Pennsylvanicus ◽  
Régime Alimentaire ◽  
Reproductive Condition ◽  
Meadow Voles ◽  
Calcium Phosphorus ◽  
Males And Females

One hundred and ninety-five meadow voles, Microtus pennsylvanicus (Ord.) were captured by means of 485 traps installed each month during the summer of 1974 in four types of culture. The analysis of minerals in their diet indicates low variation in potassium levels, whereas nitrogen, calcium, phosphorus, and magnesium levels appear to be much more environment-dependent. There are a few differences between the diets of males and females. Stomach contents of captured voles do not vary significantly from one type of culture to another, but the physiological reproductive condition of the animals accounts for significant differences in stomach contents.[Journal translation]

Sélection des proies par l'hermine en captivité

1986 ◽  
Vol 64 (9) ◽  
pp. 1973-1980 ◽  
Author(s):  
Michel Raymond ◽  
Jean-Marie Bergeron
Keyword(s):  
Food Preference ◽  
Prey Selection ◽  
Food Preferences ◽  
Microtus Pennsylvanicus ◽  
Deer Mice ◽  
Albino Rats ◽  
Meadow Voles ◽  
Blarina Brevicauda ◽  
Males And Females ◽  
Number Of Individuals

Certain aspects of prey selection were studied in ermines (Mustela erminea) kept in an enclosed arena that simulated a temporary meadow. Four males and eight females were involved in the 12-h experiments. Four types of prey were used: (i) meadow voles (Microtus pennsylvanicus), (ii) deer mice (Peromyscus maniculatus), (iii) short-tailed shrews (Blarina brevicauda), and (iv) young albino rats (Rattus norvegicus). Males were more efficient at catching prey than females, both in number of individuals and number of species captured. Meadow voles and rats were the prey captured most regularly and rapidly by both males and females. Males were more efficient at catching deer mice, but shrews were rarely captured. There was a great similarity in the performance of the four males, but considerable variation was observed among the females. No food preference could be detected in these experiments. The results are discussed in relation to food preferences observed during studies of ermines in a natural environment.[Journal translation]

Anacondas’ Tales

Anaconda ◽  
2020 ◽  
pp. 49-78
Author(s):  
Jesús A. Rivas
Keyword(s):  
Sex Ratio ◽  
Population Model ◽  
Lower Number ◽  
The Other ◽  
Wet Season ◽  
Death Rates ◽  
In The Wild ◽  
Males And Females ◽  
Number Of Males ◽  
Very High

This chapter examines the lives and tribulations of anacondas. Anacondas, like humans, produce the same number of males and females because the sex ratio is determined by sexual chromosomes. If the sexes start out equally abundant, why would there be so many more males out there in the wild? In some vertebrates one sex or the other disperses away from the area they were born. However, the author does not believe migration plays a significant role with anacondas. For starters, males are the sex with the wanderlust, not females. As such, this would not account for the lower number of females. Moreover, migration should not be very high due to the fact that the study site is the only region that holds water, so animals might move out in the wet season, but they would likely come back in the dry season, when the author did most of the sampling. If migration is not the answer for the uneven sex ratio, one is left with mortality of females as the only explanation. If females suffered higher death rates, that could explain the male bias in the population that the model estimated. Looking further into the results of the population model, the author found that females have a lower estimated survival than males. The chapter then considers the reasons females have higher mortality. The large expenditure in reproduction females incur might result in death not only as a result of predation but also during or after feeding due to weakening.

Dimorphisme sexuel et régime alimentaire de l'hermine dans un agrosystème du Québec

1984 ◽  
Vol 62 (4) ◽  
pp. 594-600 ◽  
Author(s):  
Michel Raymond ◽  
Jean-Marie Bergeron ◽  
Yves Plante
Keyword(s):  
Feeding Habits ◽  
Microtus Pennsylvanicus ◽  
Feeding Strategies ◽  
Important Food ◽  
Meadow Voles ◽  
Blarina Brevicauda ◽  
Food Components ◽  
Dimorphisme Sexuel ◽  
Sorex Cinereus ◽  
Males And Females

Variations in the diet of the ermin (Mustela erminea) were studied from 1978 to 1980 in relation to the relative availability of meadow voles (Microtus pennsylvanicus), the dominant mammal of Southern Quebec agrosystems. The analysis of 328 ermine scat samples showed that the vole does constitute the main prey item, but that the masked shrew (Sorex cinereus), the short-tailed shrew (Blarina brevicauda), and various birds are also important food components. Male ermins have more flexible feeding habits than females, who eat mostly meadow voles whatever their relative abundance. Both males and females fail to make full use of the shrews and avoid prey that weigh more than 50 g. Overlap of their realized alimentary niches is thus considerable except when small mammals are scarce. In that case, males and females use different feeding strategies; however, the hypothesis suggested by J. H. Brown and R. C. Lasiewsky (1972. Ecology, 53: 939–943) does not seem to be confirmed. The evolution of size dimorphism in this small mustelid is discussed; our results confirm the intra-sexual selection hypothesis proposed independantly by S. Erlinge (1979. Oikos, 33: 233–245) and P. J. Moors (1980. Oikos, 34: 147–158).[Journal translation]

Seasonal variations in the mass and composition of brown adipose tissue in the meadow vole, Microtus pennsylvanicus

1969 ◽  
Vol 47 (4) ◽  
pp. 547-555 ◽  
Author(s):  
L. A. Didow ◽  
J. S. Hayward
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Seasonal Changes ◽  
Microtus Pennsylvanicus ◽  
Meadow Vole ◽  
Relative Mass ◽  
Laboratory Studies ◽  
Meadow Voles ◽  
Percentage Composition ◽  
Brown Adipose

Wild meadow voles were collected each month of the year and analyzed for the mass and composition of their brown adipose tissue. The relative mass of brown adipose tissue decreased with increasing body weight in both summer and winter.Seasonal changes in the relative mass of brown adipose tissue were inversely related to seasonal changes in ambient temperature. In mature voles, the relative mass of brown adipose tissue was lowest during summer (0.5%) and increased rapidly to a level of 1.7% in early winter. Similarly, immature voles had their lowest relative mass in summer (1.0%) and increased this to 2.3% in winter. Both groups showed some decrease in the winter amount of the tissue when the subnivean environment became established. The percentage composition of brown adipose tissue with respect to water, lipid, and protein did not change significantly through the year.The results provide corroboration for laboratory studies which show that the mass and composition of brown adipose tissue are related to the requirement for cold thermogenesis. In voles, this requirement was present throughout the year and varied only in degree.

Macrogeographic variation in mitochondrial DNA of meadow voles (Microtus pennsylvanicus)

1989 ◽  
Vol 67 (1) ◽  
pp. 158-167 ◽  
Author(s):  
Yves Plante ◽  
Peter T. Boag ◽  
Bradley N. White
Keyword(s):  
Mitochondrial Dna ◽  
Fragment Length Polymorphism ◽  
Microtus Pennsylvanicus ◽  
Meadow Vole ◽  
Population Fluctuations ◽  
Meadow Voles ◽  
Mtdna Sequence ◽  
Nucleotide Divergence ◽  
Phenotype Diversity ◽  
Single Locality

Mitochondrial DNA (mtDNA) from 99 meadow voles (Microtus pennsylvanicus) collected in 13 localities and from 2 Townsend's voles (M. townsendii) from a single locality was assayed for restriction fragment length polymorphism (RFLP) with 13 restriction endonucleases. There was evidence of extensive mtDNA sequence heterogeneity within and among meadow vole populations. Thirty-eight different mtDNA composite phenotypes were found. Two common mtDNA composite phenotypes were shared among five populations, the other mtDNA composite phenotypes being characteristic of individual populations. Estimates of nucleon diversity (ĥ) were high (0.303–0.893), as were measures of intrapopulational nucleotide divergence (px values ranged from 0.0 to 0.038). Population fluctuations and periodic dispersal are the likely mechanisms maintaining high mtDNA composite phenotype diversity in meadow vole populations. Overall interpopulational nucleotide divergence (pxy) was also high (values ranged from 0.007 to 0.045). Cluster analysis clearly separates M. pennsylvanicus and M. townsendii and suggests the separation of the meadow vole populations into eastern and central groups, but there is little evidence of structure within the regional groups. Based on the zoogeography of the populations sampled, the mtDNA RFLP data support the differentiation of Microtus pennsylvanicus into at least two previously described subspecies.

Sign in / Sign up

Export Citation Format

Share Document