Abstract
Similar in effect to predators, egg parasitoids could have a significant effect on the distribution of host and its’ population dynamics. However, knowledge about the biology and ecology of aquatic parasitoids and their effects on the host are very limited. The aim of this study was to determine whether the density of parasitoids is affected by several environmental determinants and if there is a temporal change of density during the season, particularly in relation to the host population dynamics (from order Odonata in this study). In total, 266 individuals of parasitoid wasps (from four families utilizing damselflies as hosts) were identified. The density of parasitoids did not change significantly during the season regardless of the population dynamics of model host L. sponsa and other odonates, while there was a significant effect of habitat type on the density of parasitoids. This indicates that eggs of Odonata represent only one of several host taxa. This indicates that egg parasitoids of aquatic invertebrates are host generalists preferring open over afforested habitats.