Some disgusting facts you may not want to know about the common bed bug, Cimex lectularis:

• They originally parasitized bats, but inevitably discovered Stone Age people sharing the same caves and switched hosts. They find us when we are asleep using sensors for body heat, exhaled carbon dioxide, and the smells of sweat, sebaceous gland discharge, and ear secretions.
• When feeding, they inject a saliva cocktail with dozens of compounds including anesthetics to avoid detection, and vasodilators and anti-clotting agents to keep blood flowing. They can drink up to twice their weight in blood in a feeding session.
• Feeding prompts the males to gang inseminate females that are so engorged with blood they can’t escape or resist. Males use spear-like genitalia to pierce the female abdominal wall and spew semen into her body cavity.
• A home invasion can start with a single, gravid female carried into a building in luggage or furniture. They can survive months of total starvation by hiding and entering a sort of hibernation state.
• Researchers studying laboratory populations have to sustain them with fresh blood, either directly from volunteers or from artificial feeders filled with warm animal blood. People ingested them for medicinal purposes well into the 20th century in Europe and North America.

Image: A closeup view of a bedbug (Cimex lectularis) by Janice Harney Carr, Centers for Disease Control and Prevention [Public domain], via Wikimedia Commons