Insect host plant selection in complex environments

• Insect herbivores deal with a vast spectrum of information from many sources.
• Limitations in host plant choice accuracy in polyphagous insects may be mitigated by behavioural plasticity.
• Specific blends and occasional key compounds provide information about ecological factors.
• Functional characterization of insect chemoreceptors reveals evolutionary patterns.
• Mechanisms of behavioural plasticity are being elucidated in the insect nervous system.

Selection of suitable host plants is essential for the development and survival of herbivorous insects. Here we address behavioural mechanisms and the role of olfactory cues governing host choice, and their adaptive significance in complicated ecological contexts, with a focus on polyphagous insects. We also consider how recent developments in the study of olfactory systems of insects can provide a functional description of physiological mechanisms behind host plant choice. This may apply from the broader evolutionary history and local adaptations of olfactory receptor genes, to the underlying neural mechanisms behind innate host preferences and experience-based plasticity in host plant choice.