Genetic changes in an irradiated population of wild meadow voles (Microtus pennsylvanicus)

1986 ◽  
Vol 64 (3) ◽  
pp. 698-703 ◽  
Author(s):  
Howard A. Ross
Keyword(s):  
Genetic Structure ◽  
Population Growth ◽  
Gamma Radiation ◽  
Radiation Treatment ◽  
Late Summer ◽  
Microtus Pennsylvanicus ◽  
Low Density ◽  
Meadow Voles ◽  
Genetic Characteristics ◽  
And Control

Changes observed in the genetic structure of a wild population of meadow voles (Microtus pennsylvanicus) exposed to chronic gamma radiation are compared with those observed in a nearby unirradiated population. An average exposure of 14.6 ± 0.8 mGy/d of gamma radiation was administered from a 137Cs field irradiator to an otherwise unmanipulated population over 47 weeks. The demographic and genetic characteristics of the populations were estimated by livetrapping and by electrophoresis of the polymorphic plasma proteins encoded by transferrin and leucine aminopeptidase, respectively. Both the irradiated and control populations showed highly synchronous demographic changes: an autumn decline, very low density throughout the winter, a late spring increase, and late summer peak. Allele frequencies and F-statistics fluctuated dramatically throughout the low-density phase. Coincident with the acceleration of population growth, the genetic variables began to converge in the two populations. At the termination of the experiment, when population growth was slowing, the irradiated and control populations were genetically very similar. Sexual activity, longevity, and recruitment were each homogeneous among genotypes in both populations. The radiation treatment had no apparent effect on the genetic structure of the vole population. Gene flow at the beginning of an increase phase is suggested as a possible cause for convergence of the genetic attributes of the irradiated and unirradiated populations.

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.

L'utilisation de ressources alimentaires avec ou sans composés secondaires connus par une population cyclique de Campagnols des champs (Microtus pennsylvanicus)

1984 ◽  
Vol 62 (4) ◽  
pp. 601-607 ◽  
Author(s):  
Jean-Marie Bergeron
Keyword(s):  
Microtus Pennsylvanicus ◽  
Feeding Habit ◽  
Low Density ◽  
Meadow Voles ◽  
Cost Benefits ◽  
Diet Analyses ◽  
Plant Sampling ◽  
The Cost ◽  
By Products ◽  
Very High

Results from 3 years of plant sampling and diet analyses in a cyclic population of meadow voles (Microtus pennsylvanicus) have shown that animals use a lot of plants with known toxic by-products while the population is in its growth and peak phases, whereas voles from the low density phase of the population almost exclusively eat plants without such by-products. Considering the fact that plants which contain toxic by-products are "bad resources" for herbivores, while plants which do not are "good resources," one can infer from the results that the quantity of good resources available becomes very limited; this explains the appearance of bad resources in the diet at times when the population density becomes very high. There is no evidence in the literature of acute or chronic toxic effects in meadow voles resulting from the ingestion of plants with toxic by-products; thus at present one can only note the importance of such resources in their diet and speculate on the cost–benefits of such a feeding habit.[Journal translation]

Long-term effects of infant malnutrition on the behaviour of adult meadow voles, Microtus pennsylvanicus

1992 ◽  
Vol 70 (7) ◽  
pp. 1304-1308 ◽  
Author(s):  
Kim Lee Wong ◽  
Søren Bondrup-Nielsen
Keyword(s):  
Microtus Pennsylvanicus ◽  
Standard Diet ◽  
Activity Levels ◽  
Long Term Effects ◽  
Meadow Voles ◽  
Pup Retrieval ◽  
Cumulative Duration ◽  
And Control ◽  
Poor Nutrition

Several studies on laboratory mice and rats have shown that malnutrition during infancy has a variety of long-term effects extending into adulthood. These effects are manifested in reproduction, including reduced litter sizes, reduced growth rates of the young, and skewed sex ratios, and in behaviour, including increased nervousness, decreased problem-solving ability, and reduced pup retrieval to the nest by the mother. This study investigated the effects of early malnutrition on behaviour in adult meadow voles, Microtus pennsylvanicus. Experimental animals received a standard diet diluted with pure cornstarch (1 part standard diet to 2 parts pure cornstarch) through their mothers during lactation and directly for 3 weeks postweaning. Control individuals always received the standard diet ad libitum. The cumulative duration of 13 behaviours was measured in 10-min trial periods and compared between experimental and control animals. Experimental females differed from control females in a number of behaviours, especially those involving high activity levels, whereas experimental and control males showed little difference in the behaviours performed. The behaviour profile of previously malnourished females was similar to those of both control and experimental males. Increased activity, resulting from poor nutrition, may have consequences for dispersal and spacing behaviour.

Survey and control of small mammal populations on two hardwood plantations in southern Ontario

1974 ◽  
Vol 50 (5) ◽  
pp. 181-185 ◽  
Author(s):  
Andrew Radvanyi
Keyword(s):  
Small Mammal ◽  
Late Summer ◽  
Control Measures ◽  
Effective Control ◽  
Southern Ontario ◽  
Live Trapping ◽  
Surrounding Areas ◽  
And Control ◽  
Rodent Populations ◽  
Ingredient Cost

Live trapping and tagging methods were employed to assess small mammal populations within two hardwood plantations in southern Ontario. Excessive girdling damage in past years to young planted trees necessitated an evaluation of rodent populations and development of effective control measures. The application of an anticoagulant rodenticide to oat groats bait broadcast over the study area at an ingredient cost of approximately three dollars per acre virtually wiped out the small mammals. Reinvasion from surrounding areas was, however, fairly rapid, particularly during late summer. Further research on longer term control measures using poisoned bait feeder stations is recommended.

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.

Spatial genetic structure inMilicia excelsa(Moraceae) indicates extensive gene dispersal in a low-density wind-pollinated tropical tree

2009 ◽  
Vol 18 (21) ◽  
pp. 4398-4408 ◽  
Author(s):  
J.-P. BIZOUX ◽  
K. DAÏNOU ◽  
N. BOURLAND ◽  
O. J. HARDY ◽  
M. HEUERTZ ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Spatial Genetic Structure ◽  
Tropical Tree ◽  
Low Density ◽  
Gene Dispersal
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