Seasonal changes in hemolymph amino acids, proteins, and inorganic ions of a desert millipede Orthoporus ornatus (Girard) (Diplopoda: Spirostreptidae)

Abstract

Composition of hemolymph of O. ornatus was examined seasonally. Mean amino acid concentration was highest in early summer at time of molt (June, 61.73 mg%) and lowest in winter (Dec., 22.53 mg%; Jan., 32.10 mg%). Protein concentration was lowest in fall (Oct., 11.63 mg%) and highest in early spring (March, 37.56 mg%). Na+ and Cl- were the main hemolymph ions, accounting for about half the hemolymph osmolality. Significant seasonal changes occurred in concentration of these and other hemolymph ions. Indirect evidence suggested regulation of Na+, K+, Ca2+ and Mg2+. Hemolymph osmolality was higher in winter (Dec., 295.7 mosmol; Jan., 321.6 mosmol) than in summer (June, 211.9 mosmol; Aug., 204.1 mosmol). The contribution of measured ions to osmolality was greater in summer than in winter. Fluctuations of some hemolymph parameters suggest association with developmental changes.