A female roach lays an egg case holding many eggs, which hatch into nymphs that grow into adults.
Life cycle
- Female makes an egg case (ootheca).
- The egg case holds 16 to 50 eggs in German roaches.
- Nymphs hatch and molt several times, reaching adulthood in 1 to 4 months.
Output
A German cockroach female can produce 4 to 8 egg cases in her life.
Parthenogenesis
Some species can reproduce without mating.
Control
Seal cracks, remove food and water, and use bait or call a pro.
Life stages
Cockroaches have three stages: egg, nymph and adult. The female forms an egg case (ootheca) that holds eggs. The German cockroach carries her ootheca until just before the eggs hatch. The American cockroach drops hers, often glued in a hidden place.
Numbers
- German cockroach: one ootheca contains about 30 to 40 eggs, and a female produces 4 to 8 oothecae in her life. Eggs hatch in about 28 days. Nymphs become adults in 40 to 125 days.
- American cockroach: about 14 to 16 eggs per case, hatching after 6 to 8 weeks, with adults living around 1 year or more.
Mating
Males and females mate, with the female releasing pheromones to attract males. Females can store sperm and produce multiple egg cases from one mating.
Parthenogenesis
Some cockroach species, including the Surinam cockroach, can reproduce without a male. Others can do it occasionally.
Lifespan
German cockroaches live about 100 to 200 days, American cockroaches up to 2 years.
Population growth
A single pregnant German cockroach can lead to thousands of descendants in a year under good conditions, with warm, humid places, food and hiding spots.
Health risks
Cockroaches carry bacteria and allergens that can trigger asthma, especially in children. The National Institutes of Health say cockroach allergens are a major asthma trigger in urban homes.
Control
- Seal cracks and gaps.
- Fix leaks and reduce moisture.
- Store food in sealed containers and clean crumbs.
- Use gel baits and boric acid under professional guidance.
- Take out garbage regularly.
- Call a pest control professional for infestations.
Reproductive biology
The German cockroach female carries an egg case, called an ootheca, containing about 30 to 40 eggs until just before hatching, and she can produce several cases in her lifetime. American cockroaches deposit egg cases with about 16 eggs in hidden places. Nymphs hatch looking like small adults without wings and molt 6 to 13 times over several months before reaching adulthood. German cockroaches can develop in about 100 days, and adults can live roughly 100 to 200 days. Some species can reproduce without mating through parthenogenesis, although most mate first.
Health risks and control
Cockroaches shed proteins that trigger asthma and allergies, and exposure is a major factor in childhood asthma in inner city housing. They can carry bacteria on their bodies. Control uses sanitation, sealing cracks, fixing leaks, gel baits, boric acid and traps, and professional treatment for heavy infestations. Remove food and water sources, store food in sealed containers, take out trash and keep drains clean. Sprays alone often fail because cockroaches avoid them and populations grow quickly.
Based on data from the EPA and university extension entomology programs
