Do fleas bite at night?

Summary

Fleas do bite at night, at about the same rate as during the day. This is evidenced by their feces excretion being relatively constant over 24 hours. However, unfed fleas are more active at night than day. They seem to prefer looking for a host a night. This could result in people receiving more bites at night.

Details

Fleas Live on Animals

Adult fleas live on their acquired host. They won’t willfully leave the animal. They’re permanent ectoparasites.

Host Blood Dependence

Once a flea feeds for the first time, it becomes dependent on a constant source of blood to survive. 12 hours of not feeding will result in undernourishment. Males die within 48 hours and females die within 96 hours. However, egg-producing females may die in just 24 hours. These females must regularly feed because their metabolism is taxed by egg production.

Feces Excretion

Cat fleas are vessel (capillary) feeders. The fleas exploit their host’s blood pressure, resulting in rapid blood flow. This allows adult fleas to consume much more blood than they can digest. Large amounts of feces are produced while feeding.

Time of day doesn’t significantly impact on the rate of feces excreted by fleas. Fleas defecate randomly or constantly throughout a 24 hour day Fig 1.

Locomotion

Unfed adult fleas are more active at night than day. Their activity peaks at dusk, and is lowest in the morning Fig 2. Other studies have seen similar results, with fleas being more active at night.

These studies were done with unfed fleas. They were looking for a host. The movement and activity of fleas on a host have not been studied. However, if unfed fleas are more actively seeking out hosts at night, then it’s reasonable to assume that people would be bitten more at night.

References