Insect-Microorganism Interaction Has Implicates on Insect Olfactory Systems

SIMPLE SUMMARY: Interactions between insects and microorganisms facilitate the spread of the microorganisms, which in turn affect insect behaviors. In the current paper, we reviewed how fungi, bacteria, and viruses act on insect olfaction, ranging from volatiles of microorganism, microorganism-induced changes in host volatiles, and symbiotic microorganisms that directly affect insect olfaction. Finally, we highlighted the importance of olfaction in insect-microorganism interactions and provided insights into future research directions. ABSTRACT: Olfaction plays an essential role in various insect behaviors, including habitat selection, access to food, avoidance of predators, inter-species communication, aggregation, and reproduction. The olfactory process involves integrating multiple signals from external conditions and internal physiological states, including living environments, age, physiological conditions, and circadian rhythms. As microorganisms and insects form tight interactions, the behaviors of insects are constantly challenged by versatile microorganisms via olfactory cues. To better understand the microbial influences on insect behaviors via olfactory cues, this paper summarizes three different ways in which microorganisms modulate insect behaviors. Here, we deciphered three interesting aspects of microorganisms-contributed olfaction: (1) How do volatiles emitted by microorganisms affect the behaviors of insects? (2) How do microorganisms reshape the behaviors of insects by inducing changes in the synthesis of host volatiles? (3) How do symbiotic microorganisms act on insects by modulating behaviors?