10 Tiny Red Bugs That Prove Size Doesn’t Matter (When It Comes to Annoying You)

Imagine uncovering a world of tiny, red invaders hiding in plain sight—each one more intriguing (and sometimes troublesome) than the last.

From the relentless bed bugs that keep you up at night to the nearly invisible mites on your patio, these pint-sized pests pack a surprising punch. Dive into our guide and meet the 10 tiny red bugs that you never knew you needed to know about.

1. Concrete Mites (Balaustium spp.)

Concrete Mites (Balaustium spp.)

Concrete mites are tiny, bright red arachnids commonly found on concrete surfaces. They typically measure around .7 mm – 1 mm in size and are often mistaken for clover mites.

  • Not harmful to humans, but there were some bite reports within some entomology circles in the 1990s. See here for more info.
  • Primarily feed on pollen and other insects
  • Often seen in large groups, creating a noticeable red patch on surfaces.

2. Bed Bugs (Cimex lectularius)

bed bug cimex

Bed bugs are small (1.5-6.5 mm), reddish-brown parasites/insects that feed on blood, typically at night. They go through five stages, some of which are under 3 mm in size.

  • They can survive for months without feeding.
  • Often found in mattresses, box springs, and furniture.
  • Resistant to many typical insecticides.

3. Lice (Pediculus humanus capitis)

Lice (Pediculus humanus capitis)

Lice are tiny, wingless insects that live on the hair and skin of mammals, including humans. Adult lice are about 2-3 mm in size and feed on blood, causing itching and irritation.

  • There are three main types: head lice, body lice, and pubic lice.
  • Spread primarily through close personal contact.
  • Eggs, called nits, are glued to hair shafts.

4. Spider Beetles (Ptinidae)

Spider Beetles (Ptinidae)

Spider beetles are small, reddish-brown beetles that resemble tiny spiders. They typically measure between 1.5 and 3.5 mm in size and are commonly found in stored food products.

  • Feed on a variety of dry foodstuffs.
  • Often found in bird nests and rodent burrows.
  • Capable of withstanding long periods of starvation.

5. Clover Mites (Bryobia praetiosa)

Clover Mites (Bryobia praetiosa)

Clover mites are tiny, red arachnids often found on windowsills and the exterior of buildings. They are about 0.75 mm in size and feed on plant material. They are harmless to humans.

  • It can invade homes in large numbers.
  • Their front legs are 2X the length of their other legs.
  • Most active during spring and fall.

6. Red Velvet Mites (Trombidiidae)

Red Velvet Mites (Trombidiidae)

Red velvet mites are brightly colored arachnids known for their striking red appearance. Adults can reach up to 4 mm in size and are beneficial predators in the garden.

  • Feed on insect eggs and small insects.
  • Often seen after rains.
  • Not harmful to humans.

7. Chiggers (Trombiculidae)

Chiggers (Trombiculidae)

Chiggers are tiny parasitic larvae of the mites in the Trombiculidae family. Larvae are typically under 0.3 mm in size, and their bites cause intense itching and red welts on the skin. Learn more about where chiggers live.

  • Prefer to attach to areas where clothing is tight.
  • Larvae feed on skin cells.
  • Found in grassy and wooded areas.

8. Red Flour Beetles (Tribolium castaneum)

Red Flour Beetles (Tribolium castaneum)

Red flour beetles are small, reddish-brown beetles that infest stored grains and flour. Adults are a common pantry pest, about 3-4 mm in size.

  • Capable of flying.
  • Infestations can contaminate food products, but learn more about flour beetles in the bedroom.
  • Red Flour Beetles can survive in a wide range of temperatures.

9. Red Spider Mites (Tetranychus urticae)

Red Spider Mites (Tetranychus urticae)

Red spider mites are tiny arachnids that infest plants, causing damage by sucking out plant juices. They are typically around 0.5 mm in size and are significant agricultural pests.

  • Prefer hot, dry conditions.
  • Can produce silk webbing on heavily infested plants.
  • Resistant to many pesticides.

10. Red Imported Fire Ants (Solenopsis invicta)

Red Imported Fire Ants (Solenopsis invicta)

Red imported fire ants are reddish-brown bugs known for their painful stings. Workers range from 2 to 6 mm in size and build large mounds, becoming aggressive when disturbed.

  • Stings can cause severe allergic reactions.
  • Form large colonies with multiple queens.
  • Native to South America but have spread to many other regions.