Concepts in Insect Host-Plant Selection Behavior and Their Application to Host Specificity Testing

Testing the host specificity of potential agents is an important part of biocontrol methodology. An understanding of the behavioral processes involved in selection of a host plant can be used to improve the accuracy of host specificity testing by biocontrol practitioners and others interested in predicting field host use. These behavioral processes include the sequential nature of host selection behavior, the effects of experience, and time-dependent changes of host acceptance or rejection. Each of these three aspects of behavioral science is reviewed and its potential effect on the outcome of host testing is examined. The means by which practitioners can incorporate these concepts into the design, implementation and interpretation of host specificity tests are discussed. Practical matters affected by these issues include: (a) choice of arena size and design (e.g., small cages versus wind tunnels versus open field tests), (b) duration of tests, (c) use of behavioral observations to examine the process instead of the end result, and (d)interpretation of the results of choice vs nochoice tests, sequential versus parallel tests, and open field versus cage tests. Because of the diversity of behavioral factors and the inconsistent ways in which they can produce false results in host specificity tests, guidelines cannot be generalized. Hence, all biocontrol practitioners are encouraged to become familiar with the relevant concepts and apply them appropriately.