Cockroaches are insects that go through a gradual metamorphosis. Like mayflies, cicadas, and aphids that also mature this way, they go through three developmental stages: egg, nymph, and adult. Charting the cockroach life cycle is useful for understanding gradual metamorphosis and for learning about them as pests.
In this collection of “How-to-draw” sheets, elementary kids and middle schoolers can draw semi-realistic looking cockroach eggs and cockroach nymphs for biology projects and presentations. The sheets are free, printable, and can be downloaded individually or in a single document here.
The Cockroach Egg
Cockroaches do lay eggs, but unless you get out a scalpel, you’ll never see them. That’s because the female lays an egg case (known as an ootheca) that holds all of the eggs inside. The ootheca is made of a tough material that protects the eggs from harm. Depending on the kind of cockroach, an ootheca can hold as few as 14 eggs and as many as 50, which incubate anywhere from 24 to 215 days.
When the eggs inside the ootheca hatch, the young cockroaches inside begin to take gulps of air, expanding their bodies and eventually spreading the ootheca apart like a purse, allowing them to escape. As they slip out, they shed the membrane that covered them inside the egg.
Newly born cockroach nymphs are small, delicate, and creamy white. Their skins begin to darken and harden within a few hours.
Note: After their bodies darken, most cockroach nymphs don’t change much in appearance as they grow. The pictures here and that you draw each look a little different to help represent development.
Early Stage Molt
Cockroach nymphs resemble adults, but are sometimes lighter in color, becoming progressively darker as they mature.
As the nymphs mature, they outgrow their exoskeleton and shed it in a process called a molt.
Cockroaches will molt anywhere from 6 to 13 times before reaching maturity. The time between molts is called an instar and is used to gauge the nymph’s development.
Final Stage Molt
Depending on the species of cockroach, the time from birth to final instar will be between 100 and 600 days.
At maturity, adult cockroaches will be able to mate and reproduce, and the adults of some species will have wings. An adult female can produce as many as 4,500 offspring during her lifetime. Cockroaches have lifespans of between 200 and 700 days based on their species and sex, with an average lifespan of about one year.