• Size: The female Pacific beetle cockroach can grow up to one inch long. Males are typically smaller.
  • Color: These cockroaches are dark brown with small heads and wings that reach the tip of their abdomens. They resemble, and may often be mistaken for, small brown beetles, hence their name.
  • Behavior: When threatened, the Pacific beetle cockroach will expel an irritating mix of chemicals from its abdomen to defend itself. These chemicals typically have a foul odor and, in humans, they can stain the skin and irritate the eyes.
Pacific beetle cockroaches are known to eat the bark of cypress and juniper trees. They can girdle the trunks, branches and limbs of trees, causing them to die. Large, brown areas around the crown of a tree can be an indicator of an infestation. While infestations are usually slow moving, they can be devastating, causing entire trees or groups of trees to die. Because of their affinity for these trees, Pacific beetle cockroaches may also be referred to as "cypress cockroaches."

Unlike many other cockroaches, most of which lay egg cases, the Pacific beetle cockroach gives birth to live young. Females will give birth to between 7 and 13 nymphs at a time, and gestation - development of young - usually lasts about 60 days.

Related: What Do Cockroach Eggs Look Like 

Embryonic cockroaches live inside the mother in brood sacs. Throughout their development, the mother produces nutrients for her young in the form of a yellow-colored liquid substance composed of fats, sugars and protein.

Rather than digesting the food, the embryonic cockroaches store it and convert it into a crystalline, nutrient-packed milk, commonly referred to as “cockroach milk.” According to scientists, cockroach milk is one of the most nutritious, calorically dense substances on the planet, rivaling buffalo milk, which is known to be high in calories and full of protein.

Along with its unique breeding practices, this “cockroach milk” has made the Pacific beetle cockroach the subject of study for many researchers and scientists interested in learning more about the composition and possible uses of the substance.


Tips for Cockroach Control

Because Pacific beetle cockroaches are not typically found inside homes, the preventative measures listed below are directed towards helping keep your outdoor areas free of Pacific beetle cockroaches:
  • Clean up any debris found around the base or crown of infested trees. The Pacific beetle cockroach may use these areas for nesting and breeding.
  • If you find a Pacific beetle cockroach inside your home, inspect plants for infestations and promptly remove any plants that shows signs of an infestation.
If you see cockroaches inside your home, or want to help keep them from getting inside in the first place, a pest control professional can help.