Baby Bed Bugs (Nymphs): Pictures, Size and Shed Skins

Quick answer: Baby bed bugs are called nymphs. They look like small, pale adults. Newly hatched nymphs are about 1.5 mm long, the size of a pinhead, and the oldest are about 4.5 mm. They're straw-colored or nearly see-through when hungry and bright red after a meal. Each of the five stages needs a blood meal to molt, and each molt leaves an empty, bug-shaped shell behind.^1,2,3

If you've found a tiny pale or red bug, or a see-through empty shell, this guide will help you tell whether it's a baby bed bug and what it means. For the full cycle from egg to adult, see the bed bug life cycle.

What Do Baby Bed Bugs Look Like?

Baby bed bugs have the same flat, oval shape and six legs as adults, but they're smaller and paler, with a thinner outer shell.^6,12 Their color tells you when they last ate:

• Hungry: clear, whitish-yellow or straw-colored. Unfed nymphs can be nearly invisible, especially the newest ones.^1,2,3
• Just fed: bright red and plump. This is the easiest time to spot them.^13,3
• Digesting: a dark spot shows in the belly, and the bug darkens and flattens over the next couple of days.^3,14,12

Adults are reddish-brown, about 5 to 7 mm long (the size of an apple seed), and you can tell males (pointed tail end) from females (rounded tail end) only in adults.^1,15,12 For more photos, see bed bug pictures and what bed bugs look like.

How Big Are Baby Bed Bugs?

Each stage is a little bigger than the last. Feeding also stretches them, so a fed nymph looks longer than an unfed one.¹

Lengths from the EPA; inch figures are rounded conversions. Sources:^1,14

Are There Bed Bug Larvae?

No. Bed bugs grow by incomplete metamorphosis: egg, then nymph, then adult, with no larva or pupa. Larvae (like caterpillars, grubs and maggots) belong to insects that change form completely as they grow.⁴ So when people say "bed bug larvae," they mean nymphs.

If what you found is fuzzy or worm-shaped, it isn't a bed bug. Common look-alikes include:

• Carpet beetle larvae: hairy and carrot-shaped, cream to brown.⁵
• Fleas: narrow from side to side, and they jump. Bed bugs can't jump.^16,2
• Booklice: tiny (1 to 2 mm), soft and pale, found in damp places; they don't bite.¹⁷
• Bat bugs: nearly identical to bed bugs and usually found near bat roosts. Telling them apart takes a magnifier and a close look at the hairs behind the head.^6,14,9

See bugs that look like bed bugs for photos.

How Fast Do Baby Bed Bugs Grow?

A nymph has to take a blood meal before each molt. Without a host, it stays in its current stage until it feeds or dies.^2,7 Temperature matters most. Growth is quick at about 70 to 82°F, the range experts call ideal.^6,18 It slows sharply in cool rooms and stops around 55°F, where young nymphs stop molting and very few eggs hatch.⁸

From a classic lab study; in a home, add the time nymphs wait for a meal. Source:⁸

In a warm home with someone to feed on, most nymphs molt within about 5 days of a meal, and a bed bug can go from egg to adult in about 5 weeks.^7,2 Cooler rooms or fewer chances to feed can stretch that to 4 months or more.^6,18,8

Eggs are about 1 mm, pearl-white and glued in place, and they usually hatch in under 10 days in a warm home. A female typically lays a few eggs a day.^1,2,7 See bed bug eggs for more.

Do Baby Bed Bugs Bite?

Yes. Newly hatched nymphs feed at the first chance they get, and every stage feeds on blood.^9,15 They pierce the skin with a thin beak. The bite is usually painless, and a meal takes about 3 to 10 minutes.^2,19,15

Many people don't notice the bites at first:

• About 30% of people don't react even after repeated bites, and older adults are less likely to react.^2,20
• Marks can take up to 14 days to appear.¹⁹
• In a volunteer study, most people had no reaction to their first bites, but 18 of 19 eventually reacted after repeated exposure.¹⁰

That's why you should look for the bugs and their signs, not just bites. See bed bug bites.

What Do Bed Bug Shells Look Like, and What Do They Mean?

Bed bug "shells" are the skins nymphs shed as they grow. Each bed bug molts five times on its way to adulthood; adults don't molt again.^3,4

• What they look like: empty, bug-shaped husks with the same outline as a bed bug, pale and see-through to light tan.^13,3,2
• Size: it depends on which stage shed it, so shells range from about 1.5 mm to 4.5 mm.^1,3
• Not eggshells: empty eggshells are about 1 mm, bean-shaped, and stay glued in place after hatching.^1,18,14
• Where they turn up: where bugs gather, such as mattress seams, behind headboards, along baseboards and where walls meet the ceiling, usually with dark spots and eggs.^13,3 See where bed bugs hide.

Do shells mean you still have bed bugs?

Not on their own. Since nymphs molt only after feeding, shells show that bed bugs were feeding and growing.^2,13 But shells, like old stains and dead bugs, can be left over from a past infestation. Only live bugs or unhatched eggs prove bed bugs are there now.¹¹ One bug can leave up to five skins, so a few shells don't mean a few bugs.³

How to tell an old infestation from an active one

1. Look for live bugs of any size, especially bright red or plump nymphs, which fed within hours.³
2. Look for unhatched eggs. Eggs older than about 5 days show an eye spot.^1,13
3. Vacuum up the old shells and spots, then check again. New shells or spots mean current activity.¹¹
4. Put interceptor traps under the bed legs. In a Purdue study, they caught about 6 times more bugs than looking alone.²¹ No catch doesn't prove no bugs, though.¹¹

Can you vacuum bed bug shells?

Yes. Vacuuming removes shells, live bugs and dead bugs from seams, tufts and cracks. It won't reliably pull out eggs, and bugs can survive inside the vacuum, so seal the bag or contents and throw them out outdoors.^22,11,2 See signs of bed bugs for the other clues to check.

How Long Can Baby Bed Bugs Live Without Food?

It depends on the stage. In a lab study at about 79°F, newly hatched nymphs lived about a month or less without feeding, second-stage nymphs about 1 to 2.5 months, and older nymphs and adults up to about 4 months.²³ Cold rooms stretch that: at 55°F or below, bed bugs can last a year or more.²

So leaving a room empty for a few weeks won't starve out an infestation.^23,2

How Do You Get Rid of Baby Bed Bugs?

The same way you get rid of adults. Nymphs hide in the same cracks and die from the same treatments.^2,11,22

• Plan on follow-ups. Eggs keep hatching after the first treatment, so pros usually come back at least twice, about two weeks apart.²⁴
• Use heat. Running dry clothes and bedding in the dryer on medium-high heat for 10 to 20 minutes kills all stages. A full or damp load needs longer, about 30 minutes.^2,25 In whole-room heat treatments, holding hiding spots at about 118°F for 90 minutes kills all stages.¹¹
• Or use cold. Holding items at 0°F for 3 days kills all stages.²⁵
• Vacuum, encase and monitor. Vacuum seams and cracks, put bed bug covers on the mattress and box spring, and use interceptor cups under the bed legs.^22,21 One option is ClimbUp interceptors (we earn a small commission).

Found baby bed bugs? See how to get rid of bed bugs, natural remedies rated by the evidence and how to choose an exterminator. For free quotes from local bed bug exterminators, call 1-877-673-2704 (we may be paid when you call), or ask an exterminator online (we may be paid when you use this link).

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