What Does Bed Bug Larvae Look Like?

by | Mar 28, 2016 | Bed Bugs Facts

bed bugs and their eggs

Bed Bug Larvae

Anyone who has experienced a bed bug infestation will tell you that it isn’t fun.  To help you decide whether or not you have a bed bug problem, it is important that you are aware of the life cycles of the bed bug.  Or more specifically, you need to learn what bed bug larvae looks like so that you can quickly identify them and decide the best course of bed bug extermination to take.

There are seven stages to the life-cycle of a bed bug, five of which are stages of bed bug larvae.  Bed bugs go through what is known as “gradual metamorphosis.”  This means that there is no pupal stage. Each larvae stage requires feeding on blood, followed by molting so that they can move to the next stage.

bedbug life cycle (infographic)

Bed Bug Life Cycle

The Seven Bed Bug Life Cycle Stages

  • Egg — This is the obvious beginning. Bed bugs are around 1 mm long, and difficult to see.
  • First Stage Larva (1st instar) — Once a bed bug has hatched, its primary job is to hunt out a blood meal so that it can molt and move to the next stage.  At this point, it is barely bigger than its egg at only 1.5 mm.
  • Second Stage Larva (2nd instar)— Growth is continuing.  Now the bed bug larvae are at 2 mm.
  • Third Stage Larva (3rd instar) — At nearly half of its expected adult size, the bed bug has reached 2.5 mm.
  • Fourth Stage Larva (4th instar) — Having grown to 3 mm, the bed bug is on the final stretch to becoming an adult.
  • Fifth Stage Larva — This is where the bed bug larvae experience a growth spurt.  Between the fourth and fifth stages, there is a 50% gain in size, bringing the larvae up to 4.5 mm.
  • Adult — At long last, the bed bug larvae has become an adult.  Its full size of 5.5 mm has been reached, and now it is ready to begin reproduction to further the line.

Egg to Adult Process

The entire process from egg to adult takes around a month, and the scary part is that a bed bug can live for several months without feeding. Through the larvae stages, bed bugs remain relatively the same in appearance, the only real visual difference being their slow progression in size.  Adults are fatter than their previous cycles, but the naked eye probably won’t be able to tell the difference.

baby bed bug just fed

Picture of baby bed bug just fed. We can notice when we see the red color (blood). CDC/ Harvard University, Dr. Gary Alpert; Dr. Harold Harlan; Richard Pollack. Photo Credit: Piotr Naskrecki.

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