The bed bug life cycle has several stages, but it only takes about 37 days for this pest to go from egg to adulthood.
To defeat the enemy, you must understand its ways: The ability to recognize eggs, nymphs, and adult bed bugs during any of their five developmental life stages is indispensable for identifying and controlling them.
Bed bug eggs
The bed bug life cycle begins like that of most insects—with an egg. Bed bugs will only romance to fertilize eggs after a blood meal. They meet back up at their harborage (a community of bed bugs) and mating begins. According to the research of Dini Miller, PhD, at Virginia Tech, bed bug procreation is a brutal business: “The male pushes his paramere [reproductive organ] through the female’s body wall,” Dr. Miller says. “She does kind of have a receptacle for his paramere—called the spermalege—but he still wounds her in the process of ‘traumatic insemination.'” She then lays eggs and, six to nine days later, baby bed bugs hatch. Check out what bed bug eggs look like so you can find and eliminate infestations faster.
There’s no time for mom and nymph—or instar—to bond: After hatching, a nymph must find a host (you) and get some blood to grow into its next stage of life. This first-stage nymph is particularly vulnerable; because of its size (just 1.5 millimeters), it can’t travel as far as older nymphs to find a host. If the nymph is successful, the meal will also help it molt (shed its exoskeleton). Eggs and molted skins are signs of bed bugs, but here’s what else you should be looking for.
In this early stage of the bed bug life cycle, the clock is ticking for these tiny nymphs to find a blood meal. “A first-stage instar bed bug can only go an average of 20 days without feeding before it starts to die of dehydration,” says Miller. There are a total of five nymph (instar) stages, and the bugs must keep feeding throughout.
“For bed bugs, blood meals help them with moisture,” explains Jody Green, PhD, an urban entomologist at the University of Nebraska-Lincoln. “Being tucked in crevices under optimal temperatures of 70 to 90 degrees helps, too. This is why it’s hard to say how long they can live without a blood meal in real-life situations compared to laboratory settings where the climate is often controlled.” Here are pictures of bed bugs in and outside of the lab.
Adult bed bugs
With each stage of the bed bug life cycle, a bed bug grows about another half millimeter, reports the Environmental Protection Agency. After the fifth instar stage, the insect becomes a full-fledged adult bed bug of about five millimeters—and it’s ready to mate. How long bed bugs live is still a mystery, says Miller. She says the most recent research is from well-fed bed bugs in labs with optimal temperatures, where they live between 99 and 300 days. In your home, with varying temperature and humidity, the lifespan is bound to be different—but the causes of bed bugs remain consistent.