2
M. E. SOLOMON
developments in mathematical modelling, nor the methods of sampling
and counting animals. I shall touch only incidentally on philosophical
questions such as whether the numbers of animals are regulated or not,
and consider instead how to assess the degree of regulation. However,
this cannot be done effectively unless there is understanding between
writer and reader as to what is meant by this term and certain others.
To make these matters clear, I have included explanations of terms
and a simple framework of ideas about natural control, which I hope
will show the bearing of the topics discussed upon the central problem
of how the numbers of animals are regulated.
I n the last few years a good deal of new information has become
available through studies of insect and mite populations in the field
and in small-scale experiments. At the same time, new or newly
adapted methods of analysing population dynamics have been introduced and put to work on the results of these investigations. The most
notable body of new data and methods comes from studies of forest
insects in England (by Varley and Gradwell), the Netherlands (by
Klomp and his colleagues) and particularly in Canada. I shall make
frequent reference to the recently published account, by Dr R. F. Morris
and his colleagues of the Green River Project, on the spruce budworm
in the fir and spruce forests of New Brunswick. This project is remarkable for the concentration of manpower over an extended period, for
the broad approach to what is a major economic problem, and for the
amount of attention devoted to problems of measurement, analysis and
mathematical formulation. Other data I have found very instructive
include those'of Richards and Waloff (1961) on the broom beetle and
those of Holling on predation.
The new data are particularly welcome to students of insect population
dynamics, since their thinking has generally suffered from an insufficient
basis of ascertained fact. The information that has been available has
been mainly derived from laboratory experiments, from biological and
chemical control undertakings in partly or completely unnatural
circumstances, from the simpler examples of regulation in the field,
or from investigations that did not go far enough, or not in the right
directions, to uncover the regulatory processes. There has been a special
shortage of facts about the more difficult, but widely typical, populations that are members of complex communities and subject to mani.fold influences. The work on forest insects is now providing more data
of this sort. It would be valuable, from this point of view, if more
of the original observations on the spruce budworm were published.
The report (Morris, ed. 1963) presents the relationships found, in impressive completeness, but includes very little of the observational data.
At this stage the problems of how to set about analysing the dynamics
M. E. SOLOMON
developments in mathematical modelling, nor the methods of sampling
and counting animals. I shall touch only incidentally on philosophical
questions such as whether the numbers of animals are regulated or not,
and consider instead how to assess the degree of regulation. However,
this cannot be done effectively unless there is understanding between
writer and reader as to what is meant by this term and certain others.
To make these matters clear, I have included explanations of terms
and a simple framework of ideas about natural control, which I hope
will show the bearing of the topics discussed upon the central problem
of how the numbers of animals are regulated.
I n the last few years a good deal of new information has become
available through studies of insect and mite populations in the field
and in small-scale experiments. At the same time, new or newly
adapted methods of analysing population dynamics have been introduced and put to work on the results of these investigations. The most
notable body of new data and methods comes from studies of forest
insects in England (by Varley and Gradwell), the Netherlands (by
Klomp and his colleagues) and particularly in Canada. I shall make
frequent reference to the recently published account, by Dr R. F. Morris
and his colleagues of the Green River Project, on the spruce budworm
in the fir and spruce forests of New Brunswick. This project is remarkable for the concentration of manpower over an extended period, for
the broad approach to what is a major economic problem, and for the
amount of attention devoted to problems of measurement, analysis and
mathematical formulation. Other data I have found very instructive
include those'of Richards and Waloff (1961) on the broom beetle and
those of Holling on predation.
The new data are particularly welcome to students of insect population
dynamics, since their thinking has generally suffered from an insufficient
basis of ascertained fact. The information that has been available has
been mainly derived from laboratory experiments, from biological and
chemical control undertakings in partly or completely unnatural
circumstances, from the simpler examples of regulation in the field,
or from investigations that did not go far enough, or not in the right
directions, to uncover the regulatory processes. There has been a special
shortage of facts about the more difficult, but widely typical, populations that are members of complex communities and subject to mani.fold influences. The work on forest insects is now providing more data
of this sort. It would be valuable, from this point of view, if more
of the original observations on the spruce budworm were published.
The report (Morris, ed. 1963) presents the relationships found, in impressive completeness, but includes very little of the observational data.
At this stage the problems of how to set about analysing the dynamics