The world is full of insects. Many of them are beneficial, like bees and butterflies, which are essential for pollination, but some can cause damage to property and spread disease.

In order to control and eliminate harmful insects, it’s crucial to understand the life cycle of pests and their importance to pest management.

What Is the Pest Life Cycle?

Insects, like all living things, have life cycles. A life cycle is a series of developmental changes that an organism goes through during its lifetime.  

There are two main insect life cycles: complete metamorphosis and complete metamorphosis.

“Metamorphosis” refers to an organism’s dramatic transformation during its development. Often, metamorphosis also results in changes in the organism’s behavior as well as its habitat.

All insect life cycles begin with eggs.

In incomplete metamorphosis, a pest goes through three life stages: Egg, nymph, and adult. The nymph form of the insect looks similar to how it would appear as an adult.

Examples of insects that undergo incomplete metamorphosis include the following:

  • Bed bugs
  • Cockroaches
  • Earwigs
  • Termites
  • Aphids
  • Mayflies

Meanwhile, in complete metamorphosis, a pest goes through four life stages: Egg, larva, pupa, and adult. The juvenile form of the insect looks vastly different from its adult version, and they may have different habitats and feeding habits.

Examples of insect pests that undergo complete metamorphosis include the following:

  • Carpet Beetles
  • Houseflies
  • Mosquitoes
  • Fruit Flies
  • Clothes moths

Additionally, some insects go through little or no metamorphosis. These insects are described as “ametabolic.” An ametabolic insect hatches from an egg, looking like a smaller version of its adult form. One example of an ametabolic pest is the silverfish.

How Long Do Pest Life Cycle Stages Last?

How long each stage takes depends on various factors, including:

  • The Pest Species: Different insect species have different life cycles and, in turn, varying lengths of cycle stages. For example, the mayfly’s nymph stage can last up to two years in some species, while a cockroach can remain a nymph for one to three months.
  • Temperature: Some species of insect pests may develop faster in warmer temperatures, such as during the spring and summer seasons.
  • Availability of Food: Lack of food may cause some pests to develop more slowly, while an abundance of food speeds up development.
  • Disease: The normal development process of insects may be affected if they have a disease. In fact, they may not develop at all.
  • Insecticides: Exposure to insect control chemicals can kill insect pests, ending their life cycle. These chemicals can also interrupt insect development, making insects more vulnerable to disease or making them less likely to reproduce.

Why Is It Important to Know the Life Cycles of Pests?

Knowing the life cycles of household pests is crucial to ensuring the success of a pest control program. This is because of the following reasons:

  • It helps you identify what kind of pest you’re dealing with, regardless of its stage. For instance, the larvae of some pests may look very different from their adult forms.
  • Some pest control products work best at specific stages of a pest life cycle.
  • It helps you choose the right pest control products and methods, as well as utilize them when they are most effective. Some pest control products are more effective at controlling pests at specific life cycle stages.

Take, for example, fleas. Anyone who has ever experienced a flea infestation at their home or place of business knows how difficult it is to get rid of these insects without professional assistance.

Part of the reason is that fleas, during their pupa stage, are resistant to all forms of insecticides and repellents. Adult fleas also reproduce quickly; fleas in the egg stage can lay dormant for weeks to months.

The life cycle of pests must be disrupted to help ensure complete elimination and prevent future reinfestations.

Life Cycles of Three Common Household Pests

The following are some pests commonly found in homes and their life cycles.


These insects are common in households across the U.S. They carry disease-causing bacteria, mold, and viruses.

Stage 1: Eggs

These insects begin life as eggs. Adult cockroaches lay cases called oothecae, which are small, brown, and oval-shaped. The egg cases of different cockroach species may differ in appearance. For instance, American cockroaches have dark brown and ridged oothecae, while German roaches are light brown and smooth.

Cockroach cases are usually about ¼ inch long and 1/8th wide. Depending on the species, one can contain anywhere between 10 to 50 eggs.

These cases are often found in dark, hidden places, such as the gaps between furniture, in cracks and crevices, on ceilings and walls, as well as under home appliances. They can also be found in moist and humid places, such as bathrooms and laundry rooms.

Cockroach eggs hatch within 20 to 100 days.

Stage 2: Nymphs

Nymphs emerge when eggs hatch. They initially have soft, light-colored bodies. At this stage, cockroaches will molt several times until they develop wings and achieve their adult form. The nymph stage lasts for about one to two months, depending on the species and environmental conditions. Cockroaches are particularly vulnerable to insecticides at this stage.

Stage 3: Adult

At this stage, the cockroach begins the life cycle again by reproducing and making more eggs. Note that, depending on its species, an adult female cockroach can lay 300 to 1000 eggs in its lifetime.


These insects not only cause painful, itchy bites. They also spread disease.

Stage 1: Egg

Some species of mosquitoes lay eggs near bodies of water, while others do so directly on the surface of water. Mosquitoes prefer stagnant water or areas that flood frequently. Depending on the species, mosquitoes can lay 50 to 300 eggs at a time. The Aedes aegypti mosquito, which can transmit dengue, Zika, and yellow fever, can lay over 1,000 eggs in its lifetime.

Stage 2: Larva

After 24 to 48 hours, mosquito eggs hatch into larvae. Also called “wrigglers,” mosquito larvae feed on microorganisms in the water and are dependent on their habitat for survival. If the water dries out, they die.

Stage 3: Pupa

During the pupa stage, mosquitoes still live in the water but do not feed. They will also die if the water they’re in evaporates.

Stage 4: Adult

After two days to two weeks, an adult mosquito emerges from the pupa. It dries its wings and flies away. After taking a blood meal from a human or animal host, the adult mosquito begins the life cycle anew by reproducing.

Bed Bugs

These insects are notoriously difficult to control and require an integrated pest management approach that combines insecticides and non-chemical methods.

Stage 1: Egg

A female bed bug can lay up to about 50 eggs at a time. Bed bug eggs are white and about 1 mm long, and they can be seen with the naked eye.

Bed bug eggs can be found singly or in clusters, often in the seams and joints of mattresses. Bed bugs also lay eggs in cracks and crevices in frames and headboards.

Stage 2: Nymph

After about one to two weeks, the eggs hatch into nymphs. These juvenile bed bugs are lighter in color than adult ones. They molt five times before they reach the adult stage. Nymphs immediately feed on human hosts.

Stage 3: Adult

Adult bed bugs are about a quarter of an inch long and have flat, oval bodies. They are reddish-brown, with six legs. Adult bed bugs feed weekly.

Turn to the Experts in Pest Management

Controlling pest infestations is a challenging, time-intensive job, but Pest Control Unlimited is more than up to the task. We are knowledgeable about the pest life cycle, stay updated on the latest and most effective control methods and apply our expertise to our pest management approach to ensure our customers’ satisfaction.

We stand behind our work, which is why we offer a pest control guarantee. To learn more or to get a free quote, contact us today.