Population size effects on the behaviour of Libellula fulva (Odonata: Libellulidae) males, a five year study

We tested the hypothesis that population density alters male territorial and mating behaviour of dragonflies. We predicted that males at higher densities fight more and mate less. During five years we stud- ied two Libellula fulva populations along two small lowland creeks in East Hungary. Using mark-resight method we marked a total number of 1454 dragonfly males. Our results show that on the two study sites there were different population densities. At higher population densities the number of matings per male de- creased, but population size had no effect on the frequency of intraspecific fights. However, the long run study showed remarkable difference from the outcome of partial analyzes which underlines the importance of studies overtaken through several years.