Death for survival: what do we know about innate immunity and cell death in insects?

Insects are the most diverse and prolific animal group on Earth, and as such, important lessons can be taken from the elements that contribute to their evolutionary success. This review examines insect immunity and how insects combat infection with the pathogens they encounter: bacteria, viruses, fungi and parasites. Structural barriers, cellular and humoral responses and cell death all respond to specific immunological threats and contribute to the robust repertoire of immune strategies employed by insects. We discuss the strategies used by insects to combat pathogen infection and focus on what is currently known about cell death and its role in insect immunity.