THE INFLUENCE OF MOVEMENT AND RESTING BEHAVIOR ON THE RANGE OF 3 CARABID BEETLES

The need to study movement in specific ecosystems in order to understa nd population dynamics in space is appreciated among ecologists. Ecolo gical data is, however, often collected at small scales making large-s cale predictions dubious at best. To examine whether extrapolations ac ross scales are possible, we build observed behaviors affecting moveme nt of three carabid beetle species, Pterostichus cupreus, P. melanariu s and P. niger (Coleoptera, Carabidae), into a spatially explicit indi vidual-based model (IBM) to study patterns at a number of spatial scal es. Field-tracking recordings of individual beetles are fitted to a bi ased random walk (BRW) model and inserted into the IBM together with d ata on settling behavior. Beetles will often stop and rest during thei r activity periods. A range of probabilities for alternation between a ctive and resting behavior are tested in the model at several prey lev els. We found that at large scales, in this case movement over hundred s of meters and several seasons, diffusion is a good approximation for population spread. At small scales of around one meter, BRW describes movement accurately. At intermediate scales we need both BRW, resting , and changes between these behaviors to describe motion effectively i n the model. The area covered by the beetles increases linearly over t ime, while the maximum distance moved does not, indicating an approxim ately circular expansion and a thorough search of area traversed. Seas onal range and estimated rate of movement differed among species depen ding on prey availability but was not correlated to body size.