Axopodal Structures in the Malpighian Tubules of Blood-sucking Hemipterans

Abstract

Axopods have been found in the proximal region of the Malpighian tubules of two evolved blood-sucking hemipterans. They consist of a cellular expansion surrounding a sheath of regularly spaced microtubules, frequently accompanied by other cytoplasmic elements. The axopods reacted similarly to those of protozoa, retracting after 10^-5 M CuSO₄ treatment, but present after contact with dilute urea. These structures occurring more frequently in older and starved insects, they are assumed to be associated with the elimination of urate crystals, although participation in ion resorption could not be overlooked.