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Aelita Pinter - One of the best experts on this subject based on the ideXlab platform.

  • Climatic Factors, Reproductive Success and Population Dynamics in the Montane Vole, Microtus montanus
    The UW National Parks Service Research Station Annual Reports, 2004
    Co-Authors: Aelita Pinter
    Abstract:

    A variety of hypotheses has been proposed to explain multiannual fluctuations in population density ("cycles") of small rodents (for reviews see Finerty 1980, Taitt and Krebs 1985). Doubtless, such cycles - known since antiquity (Elton 1942) - result from an interaction of a multitude of factors. However, the inability of extant hypotheses, alone or in combination, to explain the causality of cycles rests in no small measure with the fact that long-term studies of the phenomenon are notoriously uncommon. The objectives of this project are to continue the long-term study of population dynamics of the montane vole, Microtus montanus, in Grand Teton National Park. Earlier observations (Pinter 1986, 1988) indicate that environmental variables might contribute to the population density cycles of these rodents, possibly by influencing their growth and various aspects of their reproduction.

  • Climatic Factors, Reproductive Success and Population Dynamics in the Montane Vole, Microtus montanus.
    The UW National Parks Service Research Station Annual Reports, 2003
    Co-Authors: Aelita Pinter
    Abstract:

    A variety of hypotheses have been proposed to explain multiannual fluctuations in population density ("cycles") of small rodents (for reviews see Finerty 1980, Taitt and Krebs 1985). Doubtless, such cycles - known since antiquity (Elton 1942) - result from an interaction of a multitude of factors. However, the inability of extant hypotheses, alone or in combination, to explain the causality of cycles rests in no small measure with the fact that long-term studies of the phenomenon are notoriously uncommon. The objectives of this project are to continue the long-term study of population dynamics of the montane vole, Microtus montanus, in Grand Teton National Park. Earlier observations (Pinter 1986, 1988) indicate that environmental variables might contribute to the population density cycles of these rodents, possibly by influencing their growth and various aspects of their reproduction.

  • Climatic Factors, Reproductive Success and Population Dynamics in the Montane Vole, Microtus montanus
    The UW National Parks Service Research Station Annual Reports, 2002
    Co-Authors: Aelita Pinter
    Abstract:

    Multiannual fluctuations ("cycles") in population density of small rodents doubtless result from the interaction of a multitude of factors, as evidenced by the variety of hypotheses proposed to explain the phenomenon (for reviews see Finerty 1980, Taitt and Krebs 1985). However, the inability of these hypotheses - alone or in combination - to explain the causality of cycles rests in no small measure with the fact that long-term studies of the phenomenon are notoriously uncommon. The objectives of this project are to continue the long-term study of the population dynamics of the montane vole, Microtus montanus, in Grand Teton National Park. On the basis of earlier observations (Pinter 1986, 1988) particular emphasis will be placed on how environmental variables, possibly acting through reproductive responses, contribute to the population density cycles of these rodents.

  • Climatic Factors, Reproductive Success and Population Dynamics in the Montane Vole, Microtus montanus
    The UW National Parks Service Research Station Annual Reports, 1999
    Co-Authors: Aelita Pinter
    Abstract:

    Multiannual fluctuations in population density ("cycles") of small rodents have been known since antiquity (Elton 1942). Numerous hypotheses have been proposed to explain this phenomenon (for reviews see Finerty 1980, Taitt and Krebs 1985). However, none of these hypotheses, alone or in combination, has been able to explain the causality of cycles, although recently removal of parasites was shown to prevent population cycles in the red grouse, Lagopus lagopus scoticus (Hudson et al. 1998). The objectives of this long-term study are to determine whether environmental variables, possibly acting through reproductive responses, contribute to the multiannual fluctuations of the montane vole, Microtus montanus.

  • Climatic Factors, Reproductive Success and Population Dynamics in the Montane Vole, Microtus montanus
    The UW National Parks Service Research Station Annual Reports, 1997
    Co-Authors: Aelita Pinter
    Abstract:

    Multiannual fluctuations ("cycles") in population density of small rodents doubtless result from the interaction of a multitude of factors, as evidenced by the variety of hypotheses proposed to explain the phenomenon (for reviews see Finerty 1980, Taitt and Krebs 1985). However, the inability of these hypotheses - alone or in combination - to explain the causality of cycles rests in no small measure with the fact that long-term studies of the phenomenon are notoriously uncommon. The objectives of this project are to continue a long-term study of the population dynamics of the montane vole, Microtus montanus, in Grand Teton National Park. On the basis of earlier observations (Pinter 1986, 1988) particular emphasis will be placed on how environmental variables, possibly acting through reproductive responses, contribute to the population density cycles of these rodents.

Aelita J. Pinter - One of the best experts on this subject based on the ideXlab platform.

  • The flea, Megabothris abantis : An invertebrate host of Hepatozoon sp. and a likely definitive host in Hepatozoon infections of the montane vole, Microtus montanus
    Journal of wildlife diseases, 2006
    Co-Authors: Raychel A. Watkins, Suzanne E. Moshier, Aelita J. Pinter
    Abstract:

    In searching for an invertebrate host for Hepatozoon sp. infecting the montane vole (Microtus montanus), we collected fleas, ticks, and mites from live-trapped voles and searched squash preparations for Hepatozoon oocysts. From 1989 through 1996, we identified six species of fleas in Grand Teton National Park: Megabothris abantis, Megabothris asio megacolpus, Aetheca wagneri, Peromyscopsylla selenis, Peromyscopsylla. hesperomys, and Hystrichopsylla dippiei dippiei. We found Hepatozoon oocysts only in M. abantis; we found no oocysts in mites or ticks. We conclude that M. abantis is an invertebrate host of Hepatozoon sp. and is likely to be the definitive host for the Hepatozoon spp. of M. montanus.

  • Gut-Associated Lymphoid Tissue in Microtus montanus from Natural Populations
    The UW National Parks Service Research Station Annual Reports, 2000
    Co-Authors: Aelita J. Pinter
    Abstract:

    Impaired immunocompetence may contribute to the multiannual fluctuations ("cycles") in population density of arvicoline rodents (Mihok et al. 1985, Pinter 1988, Lochmiller et al. 1993). In a variety of species environmental variables influence at least one component of the immune system, the gut-associated lymphoid system, GALT (Lopez et al. 1985, Li et al. 1995). Preliminary laboratory observations suggest that the development of GALT in Microtus montanus can be influenced by such factors as age and diet (Smith and Pinter 2000). However, these observations are from captive-bred voles, maintained on a synthetic laboratory diet, under strictly controlled laboratory conditions. The complexity and abundance of variables under natural conditions must influence the development and function of GALT- yet, nothing is known about it from Microtus montanus under natural conditions. The purpose of this study was essentially twofold: (1) to describe the morphometries of GALT in wild-caught M. montanus, and (2) to characterize the morphometric changes that occur in GALT of these animals as a function of their age, sex, and the season of the year.

  • Phenotypic plasticity of the montane vole (Microtus montanus) in unpredictable environments
    Canadian Journal of Zoology, 1992
    Co-Authors: Norman C. Negus, Patricia J. Berger, Aelita J. Pinter
    Abstract:

    From 1987 to 1989, the cohort dynamics of Microtus montanus populations were studied at two montane meadow sites approximately 160 km apart, in northwestern Wyoming. The 1987 and 1988 breeding seasons differed markedly from each other. In 1987, melt off occurred in April, and the first cohort was born in May (cohort 1). The entire breeding season was favorable owing to frequent rainfall throughout the summer. Cohort 1 animals grew rapidly and females began breeding at 4–5 weeks of age. Likewise, cohort 2 (June) animals exhibited rapid growth and females were breeding at 7–8 weeks of age. Cohort 3 (July and August) animals grew more slowly and most entered the winter as prepubertal animals of subadult size. At the end of the summer, cohort 3 animals represented >70% of the voles recruited during the breeding season. In 1988, following melt off in late April, precipitation was below normal and the situation intensified to severe drought through the summer. The growth rates of cohort 1 and 2 animals were sig...

  • Offspring growth and development responses to maternal transfer of 6-MBOA information in Microtus montanus
    Canadian Journal of Zoology, 1992
    Co-Authors: Patricia J. Berger, Norman C. Negus, Aelita J. Pinter, Tim R. Nagy
    Abstract:

    A study of growth and development in juvenile Microtus montanus was undertaken to determine if reproductive information derived from 6-methoxybenzoxazolinone (6-MBOA) could be transferred from the ...

  • Seasonal Variation in the Dietary Preferences of the Montane Vole, Microtus montanus
    The UW National Parks Service Research Station Annual Reports, 1992
    Co-Authors: Aelita J. Pinter, Norman C. Negus, Patricia J. Berger
    Abstract:

    From 1987 through 1989 we undertook a study in Grand Teton National Park and on the upper Green River, Sublette County, Wyoming, to measure growth rates of cohorts of montane voles, (Microtus montanus) born in May, June, July, and August. We documented dramatic differences in growth rate among cohorts, in a given year and between years (Negus, Berger and Pinter, 1992). We hypothesized that these are flexible responses to several environmental cues. Is this, however, a phenotypic response to an array of environmental cues, or is it actually a reflection of differential utilization of plant species that may exhibit different nutritional levels? This question cannot be answered at the present since virtually nothing is known about dietary preferences of Microtus montanus. However, seasonal variation in food selection has been documented in several other species on voles (Rothestein and Tamarin, 1977, Cole and Batzli, 1979, Goldberg et al. 1980) with considerable implications for winter survival and population dynamics. In Microtus montanus a similar link may exist between growth, maturation, longevity, and population dynamics on the one hand and dietary composition on the other (e.g., Pinter and Negus 1965, Berger et al. 1981, Pinter 1988, Berger et al. 1992, Negus, Berger and Pinter 1992). Consequently, we undertook a study to investigate in detail the utilization of plant resources by the montane vole, Microtus montanus. The objectives of this project are twofold: (i) to identify the plant species that constitute the diet in natural populations of M. montanus and (2) to determine seasonal food preferences in relation to the availability of plant species and to the age, sex and cohorts of the montane vole.

Donald A. Dewsbury - One of the best experts on this subject based on the ideXlab platform.

  • Conspecific odor preferences in Montane voles (Microtus montanus): effects of sexual experience.
    Physiology & behavior, 1994
    Co-Authors: Donald A. Dewsbury
    Abstract:

    Sexually naive male and female montane voles (Microtus montanus) were tested in a two-choice odor preference situation. Females, but not males, spent more time investigating bedding soiled by a conspecific of the other sex than clean, unsoiled bedding. Both naive females and males spent more time near male-soiled rather than female-soiled bedding. Males with extensive monogamous sexual experience exhibited a preference for female-soiled bedding when the comparison stimulus was clean bedding but no preference when the comparison was with male-soiled bedding.

  • Males accelerate reproductive development in female montane voles
    Journal of Mammalogy, 1991
    Co-Authors: D. Kim Sawrey, Donald A. Dewsbury
    Abstract:

    The influence of males on two measures of reproductive activation was investigated in female montane voles ( Microtus montanus ) in the laboratory. Females housed with males from weaning at 18 days of age exhibited earlier vaginal opening and earlier vaginal cornification than females introduced to males on day 38. The responses of weanling females housed across a wire-mesh barrier from males were intermediate to those of the other two groups.

Patricia J. Berger - One of the best experts on this subject based on the ideXlab platform.

  • Phenotypic plasticity of the montane vole (Microtus montanus) in unpredictable environments
    Canadian Journal of Zoology, 1992
    Co-Authors: Norman C. Negus, Patricia J. Berger, Aelita J. Pinter
    Abstract:

    From 1987 to 1989, the cohort dynamics of Microtus montanus populations were studied at two montane meadow sites approximately 160 km apart, in northwestern Wyoming. The 1987 and 1988 breeding seasons differed markedly from each other. In 1987, melt off occurred in April, and the first cohort was born in May (cohort 1). The entire breeding season was favorable owing to frequent rainfall throughout the summer. Cohort 1 animals grew rapidly and females began breeding at 4–5 weeks of age. Likewise, cohort 2 (June) animals exhibited rapid growth and females were breeding at 7–8 weeks of age. Cohort 3 (July and August) animals grew more slowly and most entered the winter as prepubertal animals of subadult size. At the end of the summer, cohort 3 animals represented >70% of the voles recruited during the breeding season. In 1988, following melt off in late April, precipitation was below normal and the situation intensified to severe drought through the summer. The growth rates of cohort 1 and 2 animals were sig...

  • Offspring growth and development responses to maternal transfer of 6-MBOA information in Microtus montanus
    Canadian Journal of Zoology, 1992
    Co-Authors: Patricia J. Berger, Norman C. Negus, Aelita J. Pinter, Tim R. Nagy
    Abstract:

    A study of growth and development in juvenile Microtus montanus was undertaken to determine if reproductive information derived from 6-methoxybenzoxazolinone (6-MBOA) could be transferred from the ...

  • Seasonal Variation in the Dietary Preferences of the Montane Vole, Microtus montanus
    The UW National Parks Service Research Station Annual Reports, 1992
    Co-Authors: Aelita J. Pinter, Norman C. Negus, Patricia J. Berger
    Abstract:

    From 1987 through 1989 we undertook a study in Grand Teton National Park and on the upper Green River, Sublette County, Wyoming, to measure growth rates of cohorts of montane voles, (Microtus montanus) born in May, June, July, and August. We documented dramatic differences in growth rate among cohorts, in a given year and between years (Negus, Berger and Pinter, 1992). We hypothesized that these are flexible responses to several environmental cues. Is this, however, a phenotypic response to an array of environmental cues, or is it actually a reflection of differential utilization of plant species that may exhibit different nutritional levels? This question cannot be answered at the present since virtually nothing is known about dietary preferences of Microtus montanus. However, seasonal variation in food selection has been documented in several other species on voles (Rothestein and Tamarin, 1977, Cole and Batzli, 1979, Goldberg et al. 1980) with considerable implications for winter survival and population dynamics. In Microtus montanus a similar link may exist between growth, maturation, longevity, and population dynamics on the one hand and dietary composition on the other (e.g., Pinter and Negus 1965, Berger et al. 1981, Pinter 1988, Berger et al. 1992, Negus, Berger and Pinter 1992). Consequently, we undertook a study to investigate in detail the utilization of plant resources by the montane vole, Microtus montanus. The objectives of this project are twofold: (i) to identify the plant species that constitute the diet in natural populations of M. montanus and (2) to determine seasonal food preferences in relation to the availability of plant species and to the age, sex and cohorts of the montane vole.

Patricia Berger - One of the best experts on this subject based on the ideXlab platform.

  • Seasonal Variation in the Dietary Preferences of the Montane Vole, Microtus montanus
    The UW National Parks Service Research Station Annual Reports, 1994
    Co-Authors: Aelita Pinter, Norman Negus, Patricia Berger
    Abstract:

    Seasonal variation in food selection has been documented in several species on voles (Rothstien and Tamarin 1977, Cole and Batzli 1979, Goldberg et al. 1980) with considerable implications for winter survival and population dynamics. In Aficrotus montanus a similar link may exist between growth, maturation, longevity, and population dynamics on the one hand and dietary composition on the other (e.g., Pinter and Negus 1965, Berger et aL 1981, Pinter 1988, Berger et al. 1992, Negus, Berger and Pinter 1992). Consequently, we undertook a study to investigate, in detail, the utilization of plant resources by the montane vole, Microtus montanus. The objectives of this project are twofold: (1) to identify the plant species that constitute the diet in natural populations of M. montanus and (2) to determine seasonal food preferences in relation to the availability of plant species and to the age, sex and cohorts of the montane vole.

  • Seasonal Variation in the Dietary Preferences of the Montane Vole, Microtus montanus
    The UW National Parks Service Research Station Annual Reports, 1993
    Co-Authors: Aelita Pinter, Norman Negus, Patricia Berger
    Abstract:

    Seasonal variation in food selection has been documented in several species on voles (Rothestein and Tamarin 1977, Cole and Batzli 1979, Goldberg et al. 1980) with considerable implications for winter survival and population dynamics. In Microtus montanus a similar link may exist between growth, maturation, longevity, and population dynamics on the one hand and dietary composition on the other (e.g., Pinter and Negus 1965, Berger et al. 1981, Pinter 1988, Berger et al. 1992, Negus et al. 1992). Consequently, we undertook a study to investigate in detail the utilization of plant resources by the montane vole, Microtus montanus. The objectives of this project are twofold: (1) to identify the plant species that constitute the diet in natural populations of M. montanus and (2) to determine seasonal food preferences in relation to the availability of plant species and to the age, sex and cohorts of the montane vole.