What environmental condition is least favorable for flea survival?

Fleas are ectoparasites that thrive in warm and humid environments, as these conditions are crucial for their life cycle and survival. Moisture facilitates the development of flea eggs, larvae, and pupae. Conversely, dry conditions are inhospitable for fleas, as they can lead to desiccation and a higher mortality rate for both adult fleas and their immature forms. Therefore, dry conditions significantly hinder the survival and reproduction of fleas, making this environmental situation the least favorable for them.

High humidity is beneficial for flea survival because it supports their developmental stages, while low temperatures can slow down their life processes but may not necessarily lead to immediate death. Heavy vegetation provides ample cover and, often, increased humidity, which promotes flea populations. Thus, dry conditions negatively impact fleas the most compared to the other choices.