How Big Can Cockroaches Get?

Cockroaches are weird little insects. They’re pint-sized in comparison to their ancient ancestors. Yet, they have been known to grow to unbelievable sizes. This has long puzzled scientists. But, a new study shows that the answer may be easier than you think. Roaches don’t grow as big as you might think, but they do take advantage of the extra oxygen by redistributing energy between their vital tissues.

The largest living cockroach species is the Megaloblatta longipennis. This species can reach a length of 9.7 centimetres, and its wingspan can reach more than 20 centimetres. There are about 30 different species of cockroach, and only a few species are considered pests. Fortunately, most cockroaches aren’t harmful to humans.

American cockroaches are reddish brown in color and can grow up to two inches in length. They are typically found near food sources. They lay eggs in ootheca, a capsule that contains fourteen to sixteen eggs, and it takes 29 to 58 days for them to hatch. The young cockroaches, or nymphs, are grayish-brown when they first hatch and turn reddish brown over the course of the next few days.

American cockroaches reach adulthood after ten to thirteen instars. They’re about 1.5 to two inches long and have a pale yellow band on the outside of their abdomen. Their lifespans are longer than those of their German cousins. American cockroaches can live as long as 400 days under favorable conditions, which is impressive for an insect of this size. These insects have the ability to resist pesticides and pathogens, and can regenerate lost limbs.