Chemical cues in disease recognition and their immunomodulatory role in insects

Preventing infections is crucial for host fitness and many insects modify their behaviour upon sensing a contagion. We review chemical cues that mediate insect behaviour in response to parasites, and diseased or dead conspecifics. Considering the large diversity of behavioural disease defences described, surprisingly little is known about disease-associated cues that mediate them, especially their chemoreceptor and neuronal details. Interestingly, disease cues do not only modify host behaviour, but they could also play a direct role in immune system activation via neuroendocrine regulation, bypassing the need for risky immunological contact with the parasite. Such crosstalk is an exciting emerging research area in insect ecological immunology that should prove invaluable in studying host-parasite interactions by combining analytical methods from chemical ecology.

Automated summary

Preventing infection is crucial for insect fitness, and many insects alter their behavior in response to disease. Chemical cues mediate this behavioral response, but little is known about the details of these cues. Disease cues not only modify host behavior, but also play a role in immune system activation via neuroendocrine regulation, bypassing the need for direct immunological contact with the parasite.