What stages are included in the life cycle of fleas?

The life cycle of fleas consists of several distinct stages: egg, larva, pupa, and adult. The correct answer highlights three of these stages—egg, larva, and pupa.

In this cycle, flea eggs are laid by the adult fleas and typically fall into the environment, where they hatch into larvae after about one to two weeks, depending on the environmental conditions. The larvae are small, worm-like creatures that feed on organic debris, such as flea feces and other detritus, and undergo a series of molts as they grow.

After the larval stage, fleas enter the pupal stage, where they spin a protective cocoon and undergo metamorphosis. This can take several days to weeks, and during this time, they can remain dormant until they sense the right conditions to emerge as adults, which is why the pupal stage is crucial for the flea's ability to survive in changing environments.

The inclusion of the pupa in the correct answer emphasizes the critical transition phase between larva and adult. It differentiates the life cycle stages effectively, showcasing the complexity and resiliency of fleas in their development.