Females of the mammalophilic species,
Boophthora erythrocephala and
Wilhelmia lineata, feed on cattle and horses in the field. When fed on the rabbit's ear under laboratory conditions, they differ considerably in bloodsucking activity, in mortality during digestion of blood, natality, and hatching rates of first instar larvae. In
B. erythrocephala 641 wild-caught-
fed in 74,1% without seasonal variation. When females were kept up to four days before feeding their bloodsucking activity did not decrease. Laboratory-emerged-
usually fed in even higher rates (416/533) and 4–6 days old flies fed more frequently than younger or older females. Survival rates during digestion of blood in 4 days were 60% in wild-caught, 40% in laboratory-emerged-
, and 74% in cattle-fed-
. Only 29% of wild-caught and the cattle-fed-
but 50% of the laboratory-emerged flies could be induced to lay eggs on wet substrate. Natality of cattle-
(219 eggs/
) and laboratory-emerged fed on the rabbit (225 eggs/
) were significantly higher than in wild-caught rabbit-fed-
(191 eggs/
). The number of eggs developing to first instar larvae generally was low (42%). In
W. lineata wild-caught-
fed less successfully (162/407) and showed considerable seasonal variation. The best results were obtained in September and October. Keeping them in the laboratory for 1–4 days reduced the bloodsucking activity. In laboratory-emerged-
the best feeding result (347/724) were obtained with 4–6 day old flies but their survival during maturation of eggs remained low (55%). It was higher with wild-caught (67%) and cattle-fed-
(78%). In all cases 60% of them could be induced to oviposit. The rabbit-fed wildcaught or laboratory-emerged flies produced significantly more eggs (183 resp. 197 eggs/
) than cattle-fed ones (138 eggs/
). Most egg batches contained only 16% fertilized eggs. In laboratory-emerged-
of
B. erythrocephala and
W. lineata the potential natality was highest in spring, lowest in summer and increased again in autumn. The number of eggs/
was affected by the blood volume. Starting with laboratory-emerged flies fed on the rabbit a production factor of 10.9 is calculated for
B. erythrocephala and of 5.4 for
W. lineata rearing from the imago to the first instar larva. When the larvae are reated to adults with 44% efficiency a reproduction of 2.4 resp. 1.2 per generation of females results.