What is the primary characteristic of immature fleas compared to adults?

Immature fleas are primarily distinguished from adult fleas by their lack of wings. In the flea lifecycle, the immature stages include eggs, larvae, and pupae, all of which do not possess wings because they have not yet developed into adult fleas. Adult fleas require wings for mobility and feeding, which is not the case for the earlier stages, which are more focused on developing and surviving until they reach maturity.

While adult fleas are indeed capable of flying, immature fleas are more ground-dwelling and rely on crawling. This distinction is important not only for understanding flea biology but also for implementing effective pest control strategies, as targeting the stages of fleas can vary between the immature and mature forms.

For context, the other options do not accurately reflect the characteristics of immature fleas. They are not larger or heavier than adults, do not possess more body segments, and although immature fleas do have different dietary needs compared to adults, such differences are not the primary distinguishing feature compared to the notable absence of wings.