Neurobiology and biomechanics of flight in miniature insects

•Miniature insects are among the smallest multicellular animals, yet many retain flight-ability.•Across insects, flight apparatus and sensory structures scale over many orders of magnitude.•Physical limits to miniaturization of sensory organs impose constraints on their function.•Smaller sensors mean worse sampling and resolution of the sensory stimuli required for flight.•Flight-related motor apparatus also faces constraints, yet miniature insects disperse widely.

Miniature insects can be as small as a few hundred micrometres in size, making them among the smallest metazoan animals ever described. Yet, even at these length scales, they display remarkably sophisticated flight behaviours. For flight at such low Reynolds numbers, miniature insects have evolved biomechanical and neural adaptations that push the boundaries of what is possible in the realm of physics and neurobiology of flight. After several decades of relative dormancy, this question has recently been revisited by researchers working in diverse areas ranging from systematics and neurobiology to dispersal behaviours. In this review, I cover recent findings in this area, and point towards the many open questions that still remain unanswered.