Insectile Swarms: Are almost immune to every attack, but will take heavy damage from explosives, fire, smoke, and electricity. They will disperse after a time.
Mosquito Swarm: A large number of blood sucking insects, they occur naturally and prolifically in swamps during spring and summer. They inflict itchy bites, and have a chance of inflicting an infection.
Hornet Swarm: A large swarm of angry insects, they occur naturally in the summer from paper nests, their stings can penetrate most cloth, they are attracted to refuse.
Biting Ant Swarm: A large swarm of angry insects, they occur naturally in the summer from ant-hills. Ants are far less immune to blunt damage than air-based swarms, they are attracted to refuse.
Fear of Fire: Many creatures, and some people, fear fire. They will avoid it regardless of how tempting a target resides near it. This applies to all living wild creatures, and all insects.
Coated in Mud: You can slaver mud on your skin to repel insects.
Insect Repellent: Your scent is deeply unpleasant to insects.