Malpighian Tubule Ultrastructure of Female Argas (Persicargas) arboreus (Acari: Ixodoidea: Argasidae) During and After Feeding

Abstract

Malpighian tubules of the female tick Argas (Persicargas) arboreus Kaiser, Hoogstraal & Kohls consist of a region of structurally different pyramidal and cuboidal cells along the entire length of the tubule. In unfed ticks, the abundant pyramidal cells are characterized by apically projected microvilli and basal membrane infoldings and contain rough endoplasmic reticulum, membrane-bound vacuoles, and microtubules. Cuboidal cells have longer microvilli and a few basal membrane infoldings; their cytoplasm contains lipidlike vacuoles associated with glycogenlike particles. As feeding progresses, pyramidal cells become rich in glycogenlike particles that could be the source of energy required during feeding. These cells are possibly involved in formation of guanine spherules as an excretory product. Cuboidal cells replace their glycogenlike particles seen in unfed ticks with lipidlike droplets, which may be the source of energy required mainly after detachment. These cells reflect features of epithelia involved in water and ion transport. Single and colonial forms of the rickettsialike symbiote Wolbachia persica (Suitor & Weiss, 1961) are distributed along the entire length of the tubule except for a few cells near the rectal sac. The single forms increase rapidly during feeding, but the colonial forms are absent.