SEASONAL FIELD ANALYSES OF WATER AND FAT-CONTENT IN THE LONG-LIVED MILLIPEDE POLYZONIUM-GERMANICUM (DIPLOPODA, POLYZONIIDAE)

Two hundred and seventy-nine Polyzonium germanicum individuals of vari ous stadia were collected seasonally in winter, late spring-early summ er (the breeding period) and early autumn. Fresh weight, dry weight an d defatted dry weight were determined for each specimen. Seasonal chan ges in water content and fat content, expressed as percentages of defa tted dry weight, were analysed in relation to body size and sex. Chang es in water content were more pronounced in the smallest individuals ( juveniles), whereas changes in fat content were more pronounced in the largest (adults). Seasonal fluctuations in water and fat content were similar in both sexes despite the sexual dimorphism of body weight. T he results suggest the following relationships within the species life -cycle: (i) water content increases during the warm months (up to 295% for juveniles in early autumn), which coincides with the moulting per iod. Oil Fat content increases subsequently to moulting; overall maxim a are reached in early autumn (population mean = 62.5%), as well as in early summer for the young. (iii) Both water and fat content decrease (to about 150% and 50%, respectively) in winter; however, there is no evidence of starvation-at least in ovigerous females which increase i n dry weight during that season. (iv) Fat content strongly decreases ( below 30% in the largest specimens) in adults of both sexes during the breeding period.