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Bed Bug Life Cycle

Bed Bug Life Cycle

The bed bug life cycle is pretty much a question of growing, drinking blood, procreating, and dying. Insects have life so easy, right? Well, the life cycle of a bed bug has a few interesting highlights, but we will be discussing all the stages of the bed bug life cycle to round out your knowledge of this age-old enemy of man.
Bed Bug Life Cycle – Egg

Like most insects, the bed bugs’ life cycle starts in the egg stage, also known as larvae. These eggs are very small, often no larger than a millimeter and a half. When they are first laid, they are white. As the bug develops inside the egg, the egg changes color to a darker red, and eventually becomes a brown color. This egg then hatches, and the nymph, as it is called, comes out. The term “nymph” refers to an immature bed bug (also applies to some other insects).

Starting from the top left, moving counterclockwise: eggs (1mm), 1st stage nymph (1.5 mm), 2nd stage nymph (2 mm), 3rd stage nymph (2.5 mm), 4th stage nymph (3 mm), 5th stage nymph (1.5 mm), unfed adult (5.5 mm), and fed adult. Photo Courtesy of Stephen Doggett, Department of Medical Entomology, Westmead Hospital, Sydney, AustraliaBed Bug Life Cycle

Bed Bug Life Cycle – Nymph

The second stage of the bed bug life cycle is a series of repeated steps – almost like a separate life cycle of bed bug nymphs. In essence, it is a cycle of “drink blood, grow, molt”. After leaving the egg, a nymph is called a first instar nymph, and is about 1.5 mm long. It will obtain a blood meal and after a short period will grow larger than its current exoskeleton can support. Thus, it will molt, or come out of its old exoskeleton with a new exoskeleton.

Then the “second instar nymph” will seek another blood meal, grow, and molt. This cycle occurs a total of five times, from first instar nymph to fifth instar nymph. At the fifth instar nymph phase, the bed bug is 4.5 mm long. It will continuously seek a blood meal, grow, and prepares itself for the next stage of the bed bug life cycle.
Bed Bug Life Cycle – Adult

After one final molting, the bedbug moves out of the fifth instar phase and becomes a mature adult bed bug. As an adult, the bed bug will seek out and consume blood, using the energy gained to produce eggs or sperm, mates, then goes to feeding again. The adult stage lasts several weeks until the bed bug dies.

Bed Bug Life Cycle

Of course, between introduction into the adult world and death, the bed bug life cycle has some interesting points.


For one thing, the female adult lays up to 5 eggs per day, as long as there is enough nutrition available. The male will also produce more sperm as long as nutrition is sufficient.

The mating process is pretty darn creepy. Whereas you may be familiar with how lots of other insects do it, the bed bug fertilization process is downright weird. The male bed bug actually plunges a syringe-like organ into the females’ abdomen, through the exoskeleton and not through any available opening.

As you can imagine, this is traumatic for the female – hence the term traumatic insemination. The female bed bug has actually developed an organ in the vicinity of the usual area for piercing called the spermelage. This organ helps to mitigate the trauma of the process.

The sperm inside the body cavity is then carried away by the hemolymph (“blood” of bed bugs) to storage receptacles called seminal conceptacles, and from there eventually to the ovaries, where actual fertilization takes cycle of a bed bug

Additional insight

Bed bugs are incredibly hardy creatures. They are known to survive for up to a year with no food. That’s why you cannot really starve them to death, because they will most likely outlast your patience. The bed bug life cycle for an active breeding adult is a few weeks long, but in harsh conditions this life cycle becomes mutable.

Bed bugs detect prey by the carbon dioxide that they release either by respiration or via the skin. Oddly enough, bed bugs cannot survive for long in conditions with high concentrations of carbon dioxide.

Bed bugs determine the fertility of their partner by looking at their size – if the female is large, then she must have just fed, and can therefore produce egg cells. Unfortunately, this causes confusion because male bed bugs drink blood and swell up too. Sometimes male bed bugs will attempt to mate with other males. At this point, the male bed bug under attack can release a pheromone that signals “alarm”, which can interpreted as “Yikes, get off me, I’m a guy!” The bed bug life cycle is truly very interesting.

bed bug life cycle

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