The helminths infesting the common lizard, Zootoca vivipara (Jacquin, 1787), were studied with special attention to the relations between the number of nematodes, Oswaldocruzia filiformis (Goezc,1782), and the size, sex and age class of the host. The possible seasonality of the parasite intensity and the relationship with the feeding habits of the host were also tested. Helminth infracommunities of Z. vivipara were depauperate with lizards harbouring only two species, the tremalode Plagiorchis molini (Lent et Freitas, 1940) and the nematode O, filiformis. A positive correlation between host size and the number of O. filiformis was found for female Z. vivipara. However, no correlation was detected between intensity and sex or age class. The feeding habits of Z. vivipara, the isolation of the population studied and the low level of interaction with other reptilian or amphibian species are suggested as the causes of the depauperate helminth infracommunities found in this laccrtid lizard.
The thermal relations, diel, and annual activity and microhabitat use of Lacerta agilis were studied in the Pyrenean isolated range of this species. Although, this heliothermic lizard demonstrated thermoregulatory capability, thermal constraints attributable to the mountain climate were observed. The activity pattern was that typical of cold temperate lizards but the beginning of activity was delayed in comparison with lowland populations. The reproductive cycle determined different activity patterns for males and females. The ontogenetic and seasonal changes in microhabitat use detected suggest influence of body size, reproductive condition in adults, and interference with other individuals in juveniles.