The physiological parameters mortality, mass, oxygen consumption and amylase activity, and microanatomical features of the digestive tract, mesenchym and reproductive organs were used to characterise starvation in Galumna elimata. The mites were reared in sterilised plastic vials containing moistened zeolite at 25°C and a 12:12 photoperiod. The control group was kept under the same conditions, but pieces of bark covered with the green bark alga, Desmococcus vulgaris (syn. Protococcus viridis), were added as food for the mites. The physiological parameters were recorded after 21 days, and the microanatomical after 21 and 42 days. The guts of the starved mites were empty or filled with mucoid substances, while the guts of control mites contained food boli formed from algal cells. The mortality was significantly higher in starved animals. The mortality after 42 days of starvation was higher in males than females. The fresh mass of starved individuals significantly decreased while the water proportion content of their body tissues increased. Oxygen consumption of the starved mites was lower. Starvation did not influence the activity of amylase. Glycogeneous granulae were characteristically absent, and mucoid substances present in the guts of mites starved for 21 days. The activity of mesenteral and caecal cells, proventricular glands and cells of salivary glands was reduced after 42 days of starvation. The cells of the seminal vesicles were reduced and contained no spermatic cells in males starved for 42 days. Starved females probably resorbed immature oocytes, but had eggs in their oviducts. Starvation induces ovovivipary or larvipary in Galumna elimata.
The oribatid mite Galumna elimata was reared under laboratory conditions on algae (Protacoccus spp.) at different temperatures (5, 15 and 20°C). Higher weight-specific amylolytic activity was found in the whole body homogenates of mites exposed to cold acclimation (5°C, 21 days) in comparison with individuals acclimated to 15 and 20°C. Accompanying parameters (live body weight, content of total soluble proteins in the body, protein-specific amylolytic activity, presence and composition of food boluses, activity of mesenteric and caecal wall cells, gregarinid parasitisation, number of glycogen granulae and guanine deposits in mesenchymal tissue, presence of proventricular glands) were investigated at all three acclimation temperatures to explain mechanisms of this change. The acclimation response of weight-specific amylolytic activity was accompanied by elevation of protein-specific amy lolytic activity. Microanatomical features did not confirm any increased secretion activity of mesenteric and caecal cells in cold acclimated animals. Granulation and apocrine secretion of these cells increased with increasing temperature as with food ingestion. The food boluses contained algae or algae mixed with unknown fungal hyphae in individuals acclimated to 15 and 20°C. The concentrated mucoid substances prevailed in animals exposed to cold, indicating lower feeding activity at 5°C. Based on these findigs, Lye hypothesised that specific amylolytic activity reflected passively the different changes in protein composition of the body at different temperatures and its elevation is without direct adaptive importance., Vladimír Šustr, Jan Hubert, and Lit