The influence of parasites on insect behaviour

In this chapter, we discuss insect behavioural responses to parasites. Dividing behaviours conceptually into those that occur before and after infection, we start by reviewing the evidence that insects identify and avoid potentially infectious environments to minimize negative consequences of infection. We then consider behavioural responses following infection according to their adaptive value to either the insect host or to the parasite. In one section, we cover sickness behaviours proposed to benefit the host by conserving energetic resources during infection; in another section, we discuss evidence for altered host behaviour as a parasite adaptation enhancing parasite survival or transmission. We briefly describe the mechanistic link between behaviour and immunity in insects, and provide a summary of methods and techniques becoming standard to studying behaviour of model insect species in the context of infection. We conclude the chapter by discussing future directions in the study of insect behavioural responses to parasites.