- The effects of feeding different types of human blood to human body lice, Pediculus humanus humanus L. (Phthiraptera: Pediculidae), on feeding success, longevity and numbers of eggs laid were investigated using an artificial blood-feeding system in the laboratory. No significant differences were found between lice fed on different human blood types for any of the parameters tested. However, when lice were fed on human blood of one blood type followed immediately by a different blood type, they took significantly smaller bloodmeals, their longevity was reduced and they laid fewer eggs per female than control lice that had been fed twice on the same human blood type. When lice were fed human blood that had been stored for 1-26 weeks, the quantity of blood taken, the proportion of lice that became fully engorged and lice longevity diminished gradually as the storage time of the blood increased, but there was no effect of storage time on the mean number of eggs laid per female. However, lice would not feed on 26-week-old blood. The type of anticoagulant used had a significant effect on the proportion fed, longevity and number of eggs laid per female. Generally, EDTA (ethylenediaminetetraacetic acid)-treated blood reduced longevity and the number of eggs laid per female to a greater degree than heparinized or citrated blood. Lice fed on rabbit blood took significantly larger amounts of blood, lived longer and laid a higher mean number of eggs per female than lice fed on human blood.