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Alfredo Salvador

Microhabitat use of Lacerta schreiberi was studied at one locality in the Cantabrian mountains of León province, Spain. Lizards do not use the microhabitat categories in proportion to their availability. Ontogenetic shifts in microhabitat selection have been observed. Juveniles are found in grass and rush areas, while adults prefer bushes. Subadults were present in both microhabitat types. Lizards perch on plants, mainly bushes, between 10 and 80 cm height. Microhabitat selection changes seasonally only in subadults.

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Alfredo Salvador and José Veiga

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Alfredo Salvador and José Martin

Abstract

The consequences of tail loss on the thermal biology of high-altitude rock lizards (Lacerta monticola) were studied by comparing field body temperatures, selected body temperatures in a gradient, and behavioural patterns of thermoregulation of tailed and tailless lizards in the field. Neither field nor selected body temperatures differed significantly between these groups. Time spent basking, mean duration of basking, and basking frequency did not differ between tailed and tailless lizards. Tailless lizards seemingly adjusted for running impairment by using rocks to a greater extent than did tailed lizards, and low morning body temperatures by increasing maximal duration of basking periods and keeping shorter distances to the nearest refuge. Tailless lizards modify thermoregulatory behaviour, but obtain the same thermoregulatory precision as tailed lizards, possibly allowing maximization of physiological processes linked to tail regeneration.

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José Veiga and Alfredo Salvador

Abstract

Many species of lizards have colour spots on the flanks that may function as ornaments. We investigate the between-years stability of the blue patch colour saturation and the relationships between colour saturation, mating success, and survival in males of the lizard Psammodromus algirus. Saturation values of the anterior blue patch of males were significantly repeatable across years. Survivors had more saturated patches than non-survivors among paired males but not among non-paired males. The positive relationship between blue patch saturation and survival suggests that this morphological trait acts as a reliable signal of male quality measured as adult survival.

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Alfredo Salvador and José F. Domínguez

Abstract

Food availability and diet composition were examined in sympatric populations of Lacerta schreiberi and Podarcis bocagei at a locality in the Cantabrian mountains (province of León, Spain). Neither species uses trophic resources in proportion to their relative abundance. Extensive overlap in diet composition has been found between P. bocagei and juvenile L. schreiberi. Although both species feed mainly on spiders, juvenile L. schreiberi eat the most abundant and P. bocagei select larger prey sizes. Subadult and adult L. schreiberi select beetles and grasshoppers.

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Valentin Pérez Mellado and Alfredo Salvador

Abstract

The behavioral thermoregulation of P. pityusensis was studied for a period of one week during August, 1980. The cloacal temperatures and the ground and air temperatures were recorded by means of thermistors. P. pityusensis behaves like a heliotermic species with a temperature range between 28.5 and 41.5 ° C. Very significant correlations were found to exist between the Tc (Body temperatures) and the Ta (Air temperatures) or between the Tc and the Ts (Ground temperatures) in all ofthe specimens analyzed. There are also significant statistical differences between te mean Tc in individuals during thermoregulation and the Tc of individuals active on the ground or inactive underneath stones. The daily pattern of activity is bimodal; the variations in body temperatures, being as a whole relatively independent of the fluctuations in the ambient temperature, adjust themselves to this pattern. P. pityusensis, roughly speaking, manifest several characteristics of the behavioral thermoregulation and pattern of activity similar to those described for other lizards such as Psammodromos algirus, inhabitants of the mediterranean region which is characterized by its hot, dry summers.