POPULATION CYCLES I N SMALL MAMMALS
389
during the population decline, with the important variable being that
the overall resistance of individuals from peak populations is lower
than that of individuals at low or increasing densities. We emphasize
that we should be concerned with the variability demonstrated by
individuals composing populations.
We think that enough is now known about the natural history of
microtine fluctuations for us to be able to devise some simple experiments to test alternative hypotheses. Field experiments in ecology
are particularly difficult to replicate properly, and part of our effort
must be geared to replicating experiments over several populations of
several species. If we spend more effort on devising, executing and
interpreting experiments, we may find less time devoted to specsc
schools defending one hypothesis at all costs. We would discourage
simple descriptive studies of microtine populations, even of species
yet unstudied, unless they are coupled with some experimental analysis.
Finally, we cannot resist making a prediction about the future.
We feel that studies of the heritability of reproductive capabilities,
growth potentials, and behavior of microtines will be the key to
unlocking the mystery of rodent cycles.
ACKNOWLEDGEMENTS
We wish to acknowledge our colleagues formerly at Indiana University, Michael Gaines, Barry Keller and Robert Tamarin, whose
efforts contributed so substantially to much of our own work reviewed
in this article. Rey Stendell and Paul Whitney made available to us
as yet unpublished results from their Ph.D. studies and we are very
grateful to be able to include their findings in this paper. The support
of the National Institutes of Health, the National Science Foundation,
the National Research Council of Canada and the Miller Institute for
Basic Research of the University of California, Berkeley made possible
our studies reported and reviewed here, and for this support we are
most appreciative.
R E F E R E N C E S
Adamczyk, K. and Walkowa, W. (1971). Ann. 2002. Pennici 8, 146-163. Compensation of numbers and production in a Mus muaculua population aa a
result of partial removal.
Anderson, P. K. (1970). Symp. Zool. SOC. Lond. 26, 299-326. Ecological structure
and gene flow in small mammals.
Andrews, R. V. (1968). Phyeiot. Zool. 41, 8&94. Daily and seasonal variation in
adrenal metabolism of the brown lemming.
Andrews, R. V. (1970). Acta Endocrinologica 65, 639-644. Effects of climate
and social pressure on the adrenal response of lemmings, voles and mice.
0
389
during the population decline, with the important variable being that
the overall resistance of individuals from peak populations is lower
than that of individuals at low or increasing densities. We emphasize
that we should be concerned with the variability demonstrated by
individuals composing populations.
We think that enough is now known about the natural history of
microtine fluctuations for us to be able to devise some simple experiments to test alternative hypotheses. Field experiments in ecology
are particularly difficult to replicate properly, and part of our effort
must be geared to replicating experiments over several populations of
several species. If we spend more effort on devising, executing and
interpreting experiments, we may find less time devoted to specsc
schools defending one hypothesis at all costs. We would discourage
simple descriptive studies of microtine populations, even of species
yet unstudied, unless they are coupled with some experimental analysis.
Finally, we cannot resist making a prediction about the future.
We feel that studies of the heritability of reproductive capabilities,
growth potentials, and behavior of microtines will be the key to
unlocking the mystery of rodent cycles.
ACKNOWLEDGEMENTS
We wish to acknowledge our colleagues formerly at Indiana University, Michael Gaines, Barry Keller and Robert Tamarin, whose
efforts contributed so substantially to much of our own work reviewed
in this article. Rey Stendell and Paul Whitney made available to us
as yet unpublished results from their Ph.D. studies and we are very
grateful to be able to include their findings in this paper. The support
of the National Institutes of Health, the National Science Foundation,
the National Research Council of Canada and the Miller Institute for
Basic Research of the University of California, Berkeley made possible
our studies reported and reviewed here, and for this support we are
most appreciative.
R E F E R E N C E S
Adamczyk, K. and Walkowa, W. (1971). Ann. 2002. Pennici 8, 146-163. Compensation of numbers and production in a Mus muaculua population aa a
result of partial removal.
Anderson, P. K. (1970). Symp. Zool. SOC. Lond. 26, 299-326. Ecological structure
and gene flow in small mammals.
Andrews, R. V. (1968). Phyeiot. Zool. 41, 8&94. Daily and seasonal variation in
adrenal metabolism of the brown lemming.
Andrews, R. V. (1970). Acta Endocrinologica 65, 639-644. Effects of climate
and social pressure on the adrenal response of lemmings, voles and mice.
0