PATTERNS OF HEMOGREGARINE LOAD, AGGREGATION AND PREVALENCE AS A FUNCTION OF HOST AGE IN THE LIZARD LACERTA-VIVIPARA

Patterns of haemogregarine load, aggregation, and prevalence as a func tion of host age in the lizard Lacerta vivipara were investigated. The se parameters may provide evidence for the potential effect of parasit es on host survival. The predictions of theoretical models concerning the shape of parasite load, parasite aggregation, and parasite prevale nce across host age were used to test if parasites are a significant s ource of host mortality. Both age-intensity and age-aggregation curves were found to be peaked, whereas the age-prevalence curve increased w ith host age, reaching high levels (>80% of infected hosts). These fin dings of humped age-aggregation and age-intensity curves are in good a greement with the predictions of the Anderson and Gordon (1982) model and suggest that haemogregarines may influence age-dependent host mort ality in this population of L. vivipara.