The effect of starvation on the metabolic rate and microanatomy of Galumnaelimata (Acari : Oribatida)

The physiological parameters mortality, mass, oxygen consumption and amylas e activity, and microanatomical features of the digestive tract, mesenchym and reproductive organs were used to characterise starvation in Galumna eli mata. The mites were reared in sterilised plastic vials containing moistene d zeolite at 25 degreesC and a 12:12 photoperiod. The control group was kep t 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, an d the microanatomical after 21 and 42 days. The guts of the starved mites w ere empty or filled with mucoid substances, while the guts of control mites contained food boli formed from algal cells. The mortality was significant ly higher in starved animals. The mortality after 42 days of starvation was higher in males than females. The fresh mass of starved individuals signif icantly decreased while the water proportion content of their body tissues increased. Oxygen consumption of the starved mites was lower. Starvation di d not influence the activity of amylase. Glycogeneous granulae were charact eristically absent, and mucoid substances present in the guts of mites star ved for 21 days. The activity of mesenteral and caecal cells, proventricula r glands and cells of salivary glands was reduced after 42 days of starvati on. The cells of the seminal vesicles were reduced and contained no spermat ic cells in males starved for 42 days. Starved females probably resorbed im mature oocytes, but had eggs in their oviducts. Starvation induces ovovivip ary or larvipary in Galumna elimata.