Preface
The use of biological control agents is increasing worldwide and there are now many
companies mass producing and selling such organisms. However, there is a great need for
quality control in the production and use of these natural enemies, because deterioration of
mass-reared biological control agents leads to failures in pest management. The area of
quality control is rather new for biological control workers. Therefore, the first book on this
topic specifically for biological control agents contains several chapters with background
information, before discussing the quality control guidelines that have recently been
developed.
The first section of the book is devoted to emergence of quality control for natural
enemies. In Chapter 1 the need for quality control for mass-produced biological control
agents is discussed. In Chapter 2 the aspects of total quality control for the production of nat-
ural enemies are described.
The second section of the book – the basis of variability in foraging behaviour of natural
enemies – comprises chapters dealing with background information on sources of variation
in behaviour that are regularly encountered, but not understood and often misinterpreted in
mass rearing. In Chapters 3 and 4, factors are analysed that induce the variability in
searching behaviour of natural enemies, and technologies are described that illustrate how to
manage this variation. Searching behaviour is influenced by the insect’s genetic constitution,
its physiological state and its experience. Chapter 5 presents an overview of the information
on the topic of food ecology of natural enemies, and illustrates that a certain physiological
state is needed before a natural enemy is able to search for hosts. These chapters make it clear
that insight into behavioural variability in the foraging behaviour of natural enemies is a pre-
requisite for proper mass rearing and efficient application of natural enemies in pest manage-
ment.
The third section focuses on how to cope with this variation. In Chapter 6 a population
genetic perspective is given on how to manage captive populations. Examples of adaptation to
captive rearing and of the trade-off with field performance are presented. Chapter 7 discusses
the effects of a transfer of natural enemies from the field to a mass production facility, such as
reduction of fitness and enhancing the possibility of fixation of deleterious mutations in the
population by genetic drift. Ways to prevent these negative effects are presented. In Chapter 8
the possibilities and advantages of unisexual reproduction for biological control are discussed.
Some evidence is found for two advantages of unisexual reproduction: (i) unisexuals are
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