Studies on the morphological changes in the midguts of two ixodid tick species Boophilus microplus and Rhipicephalus appendiculatus during digestion of the blood meal.

Light and electron microscopy were used to study the morphological changes which accompanied feeding and digestion of the blood meal in the midgut epithelium of two ixodid tick species Boophilus microplus and Rhipicephalus appendiculatus. In unfed ticks of both species, the midgut epithelium was lined by stem cells and empty digest cells in which haematin accumulated with starvation. On attachment to its hosts, differentiation of the stem cells and the loss of haematin from the midgut epithelium, seemed to be synchronous. Digestive activity with the appearance of the digest cell series started in the anterior end of the midgut when it came in contact with the blood meal. Although various stages can be distinguished, it would appear that these are in reality phases of activity of a single cell type--the digest cell. No additional evidence was obtained on other cell types.