Bloodsucking bugs are a type of insect that feed on the blood of humans and animals. The two most common types of bloodsucking bugs are ticks and fleas. Ticks are small arachnids that attach themselves to the skin of their hosts and feed on their blood. Fleas are small wingless insects that jump from host to host and feed on their blood. Both ticks and fleas can cause irritation, discomfort, and even disease in their hosts.