Biochemical and Physiological Studies of Certain Ticks (Ixodoidea). Hemolymph Volume Determined by Isotope and Dye Dilution during the Gonotrophic Cycle of Argas (Persicargas) persicus (Oken) and A. (P.) arboreus Kaiser, Hoogstraal, and Kohls (Argasidae)

Abstract

Absolute hemolymph volume (aHv) and hemolymph volume per cent (Hv%) (Aliters/100 mg body weight) of female Argas (Persicargas) arboreus Kaiser, Hoogstraal, and Kohls, and of A. (P.) persicus (Oken) (family Argasidae) were determined in different states in the gonotrophic cycle by both amaranth dye and 14C-carboxylic inulin dilution methods. The states tested were unfed, engorgement day, engorgement + 1 day, oviposition day, and oviposition completion + 1 day. The aHv in each species was least in the unfed state, greatest on engorgement day, and decreased gradually in the following states although the aHv was greater on oviposition completion + 1 day than in the unfed state. The Hv% of each species was maximal in the unfed state, decreased through engorgement day to a minimum on engorgement + 1 day, increased through oviposition, and at oviposition completion + 1 day was almost the same as in the unfed state. Most Hv% differences between states arose from the great weight changes affected by feeding and oviposition. Use of the common weight regression enabled the aHv to be estimated at any state. The 2 methods gave different values but the 14C dilution method was the more reliable for determining tick hemolymph volume. Arthropod hemolymph is the medium through which chemical exchanges between organs are effected, food is transported from the gut, waste products pass to excretory organs, and hormones are conveyed. Hemolymph also serves as a water reservoir; when the body is desiccated this water is withdrawn without desiccating tissues. It also has important roles in transmitting pressure from one body region to another, ventilating the tracheal system, hatching, and molting. In bloodsucking arthropods, hemolymph is a medium for pathogen maintenance and proliferation. Received for publication 11 May 1971. * Request reprints from Medical Zoology Department, NAMRU-3, U. S. Interests Section, Spanish Embassy, Cairo, Arab Republic of Egypt. t This work was supported in part by Agreement 03-016-1 between the NIAID (NIH) and NAMRU-3. From Research Project MF12.524. 009-3010, Bureau of Medicine and Surgery, Department of the Navy, Washington, D. C. The opinions and assertions contained herein are the private ones of the author and are not to be construed as official or as reflecting the views of the Department of the Navy or of the naval service at large. Knowledge of arthropod hemolymph volume is essential to express precise data on sugars, inorganic salts, free amino acids, and other biological solutes. The hemolymph volume of ticks has not been studied. Insect hemolymph volume has been determined by various direct and indirect methods. Direct methods are based on actual removal of the entire hemolymph (Richardson et al., 1931; Buck and Keister, 1958). Indirect methods, based on removal and comparison of hemolymph samples before and after treatment, involve measurements of dilution of hemocytes (Yeager and Tauber, 1932), dyes (Yeager and Munson, 1950), chemicals (Beard, 1949; Yeager and Munson, 1950), and radioisotopes (Levenbook, 1958). Patton (1962) determined volume by comparing the specific gravity of hemolymph before and after injecting physiological saline. Shatoury (1966) estimated volume by a technique based on the exchange of hemolymph sodium cation with ion-exchange resin. This study was undertaken to obtain comparative quantitative information on the hemolymph volume of two argasid species during