General considerations for laboratory bioassays

The first step in bioassay design is to determine exactly what behavior is to be measured. The next step is to standardize the experimental design and evaluate the significance of potential endogenous and exogenous sources of variation. 

Appropriate methods of statistical design should be identified and considered before experiments are undertaken to ensure that the data collected will conform with the assumptions of the chosen statistical test. Finally, laboratory results must be evaluated with respect to both previous findings and field observations. 

Laboratory studies offer several advantages over the field for bioassay. In the laboratory, temperature, humidity, the physiological state of the organism, and most external stimuli can be controlled to a greater or lesser extent. Laboratory-reared organisms, however, may exhibit responses different from those of wild organisms, so laboratory results are best interpreted with reference to field observations. 

An important point to consider in the design of bioassays is the complexity of the behavior being observed. In a complex process such as the identification and acceptance of a host for feeding or oviposition, several different behaviors must be released in sequence by unique stimuli. Visual or volatile chemical cues may be used to bring the insect in contact with the potential host, after which tactile or nonvolatile chemical cues may be used to actually identify the host and assess its quality for utilization. In such cases, it may be necessary to dissect the overall response into its components and develop specific bioassays for each stimulus separately, rather than to attempt to develop a consistent, discriminating bioassay that utilizes the whole behavioral process. 

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