Feeding behaviour and food choice in three populations of the millipede Glomeris hexasticha Brandt, 1833 (Diplopoda: Glomerida: Glomeridae): intra- and interpopulation laboratory study

Foraging behaviour, determined by both internal and external factors, requires investment of time and energy. Optimizing the nutritional decisions also influences efficiency during the feeding process and fitness. Feeding behaviour has been poorly investigated in millipedes. Hence, the aims of this study were to test food choice and to explore intra- and interpopulation variability in several sequences of feeding behaviour in millipede Glomeris hexasticha Brandt, 1833 under laboratory conditions. Individuals of G. hexasticha and leaf litter were collected from three populations within Belgrade, Serbia. A feeding experiment was conducted using a cross-shaped experimental maze with oak leaves, small-leaved linden leaves, and moss as potential food sources. The individuals most often chose oak leaves, subsequently moss, while linden leaves were the least preferred. Sexual dimorphism was detected only for the average time spent in maze arms that contained food items in the Ada New Belgrade population and the Hyde Park population. Intrapopulation differences that depended on feeding status and interpopulation differences in some behavioural sequences were detected. We assume that sexual dimorphism in most of the analysed behavioural traits was not detected, because both sexes had to satisfy basic nutritive requirements after the same starvation period. However, research timing may be responsible, at least partially, for the obtained results. Repeating experiments in different periods of the year or using more fresh food or food sources in different phases of the decomposition may give different results. Further, in our experimental design, some unknown preference towards particular maze arms could not be completely excluded.