Analysis of Processes Involved in the
Natural Control of Insects
M . E . S O L O M O N
Agricultural Research Council. Pest Infestation
Laboratory. Slough. England
I . Introduction ..........................................................
1
I1 . ConceptsandTerms ...................................................
3
I11 . Three Types of Processes influencing Abundance ...........................
8
A . Regulation by Density-Dependent Processes ...........................
8
B . Modification of the Regulatory Processes ..............................
9
C . Imposition of Changes in Abundance Independently of Density ............ 9
IV . Estimating the Roles of different Factors and Processes in Natural Control ..... 10
A . Variation and its Causes .............................................
10
B . Detecting and Assessing Regulation ................................... 16
C . Assessing the Role of Particular Factors ...............................
26
D . Interpreting Effects of Successive Mortalities ...........................
36
,E . The Status of Methods of Estimation .................................. 41
V . Density Relationships in the Action of Predators and Paraaites ............... 42
A . Functional and Numerical Responses of Natural Enemies ................ 42
B . A Laboratory Model of Functional Response ...........................
42
C . Functional Responses of Some Insect Parasites ......................... 44
D . Mammalian Predators of the Pine Sawfly .............................. 44
E . Functional Responses of Other Vertebrate Predators of Insects ........... 47
F . ANoteonTerms ................................................... 49
V I . Questions bearing upon a Theory of Parasite-Host Interaction ................ 49
A . Is Parasite Fecundity Not a Limiting Factor? .......................... 49
B . Do Parasite-Host Oscillations tend to Increase in Amplitude? .............. 61
C . How might Expanding Oscillations be Damped? ........................
61
Acknowledgments ......................................................... 64
References ................................................................ 64
I . INTRODUCTION
A short title may cover a wide field . The title of this article is by no
means long enough to show precisely what I propose to deal with and
which topics will be omitted . The word insects does duty for terrestrial .
insects and mites . Birds and small mammals appear only in the role of
predators upon insects . The emphasis will be on the results of practical
studies of population dynamics. especially in the field. on the sorts of
data that are needed for the study of natural control. and on their
elementary analysis . I shall not deal with statistical methods. nor
Natural Control of Insects
M . E . S O L O M O N
Agricultural Research Council. Pest Infestation
Laboratory. Slough. England
I . Introduction ..........................................................
1
I1 . ConceptsandTerms ...................................................
3
I11 . Three Types of Processes influencing Abundance ...........................
8
A . Regulation by Density-Dependent Processes ...........................
8
B . Modification of the Regulatory Processes ..............................
9
C . Imposition of Changes in Abundance Independently of Density ............ 9
IV . Estimating the Roles of different Factors and Processes in Natural Control ..... 10
A . Variation and its Causes .............................................
10
B . Detecting and Assessing Regulation ................................... 16
C . Assessing the Role of Particular Factors ...............................
26
D . Interpreting Effects of Successive Mortalities ...........................
36
,E . The Status of Methods of Estimation .................................. 41
V . Density Relationships in the Action of Predators and Paraaites ............... 42
A . Functional and Numerical Responses of Natural Enemies ................ 42
B . A Laboratory Model of Functional Response ...........................
42
C . Functional Responses of Some Insect Parasites ......................... 44
D . Mammalian Predators of the Pine Sawfly .............................. 44
E . Functional Responses of Other Vertebrate Predators of Insects ........... 47
F . ANoteonTerms ................................................... 49
V I . Questions bearing upon a Theory of Parasite-Host Interaction ................ 49
A . Is Parasite Fecundity Not a Limiting Factor? .......................... 49
B . Do Parasite-Host Oscillations tend to Increase in Amplitude? .............. 61
C . How might Expanding Oscillations be Damped? ........................
61
Acknowledgments ......................................................... 64
References ................................................................ 64
I . INTRODUCTION
A short title may cover a wide field . The title of this article is by no
means long enough to show precisely what I propose to deal with and
which topics will be omitted . The word insects does duty for terrestrial .
insects and mites . Birds and small mammals appear only in the role of
predators upon insects . The emphasis will be on the results of practical
studies of population dynamics. especially in the field. on the sorts of
data that are needed for the study of natural control. and on their
elementary analysis . I shall not deal with statistical methods. nor