Authors: Jacek M. Szymura

Abstract: Analysis of variation at four allozyme loci demonstrated that a population of the yellow-bellied toad in Göritzhain (Germany) does not represent an easternmost relict population, but is descended from Romanian toads introduced there about 15 years ago.

Authors: Adolfo Marco And Andrew R. Blaustein

Abstract: Desiccation during water recession at oviposition sites can be a major cause of embryo death in clutches of aquatic amphibians. However, aquatic eggs of the north-western salamander, Ambystoma gracile, can survive out of water for at least 30 days in the field. Females lay eggs surrounded by a firm jelly matrix which presumably protects embryos from desiccation. In a field study, embryos from clutches located either in or out of the water showed no differences in size or stage at hatching. In laboratory experiments, where genetic effects were controlled, air exposure had no effect on embryo survival rate, size or stage at hatching. The ability of A. gracile to survive prolonged droughts or water recession during embryonic development may be shared by other amphibians.

Authors: Juan M. Pleguezuelos And Mónica Feriche

Abstract: We examined 150 museum specimens of Macroprotodon cucullatus from the southern portion of the Iberian Peninsula to determine size at sexual maturity, reproductive and fat body cycles, clutch size and hatching period. Males mature at a smaller absolute and relative size than females and, as in Moroccan populations, show a postnuptial spermatogenic cycle. The mating period occurs earlier than that of any other Mediterranean snake species. Females reproduce every two years and there is no correlation between body size and clutch size. The tendency for M. cucullatus to have a biennial reproductive frequency and a fixed clutch size is discussed in relation to some features of the ecology of this species, including its burrowing habit, its likely low range of preferred temperatures in relation to epigeous species, and its low feeding frequency.

Authors: J. C. Brito, O. S. Paulo And E. G. Crespo

Abstract: We describe the habitats of the endemic Iberian lizard Lacerta schreiberi in Portugal and determine those habitat components that best explain the presence of the species. The geographic distribution of L. schreiberi in Portugal was also determined through extensive field surveys. The previously known distribution area was enlarged by 150% and new isolated populations were detected. The area occupied by the three previously known southern isolates was delimited and increased by 300%. The species is usually restricted to the margins of rivers and streams. Major habitat characteristics that correlate with the presence of the species are water velocity and quality, dominant species in the tree and shrub strata, streams surrounding the biotopes, and altitude. Nevertheless, the selection patterns that L. schreiberi seems to exhibit are only a consequence of its preference for the Atlantic climate. Consequently the presence of the species in a given watercourse seems to be more dependent on the climate of that region than on the intrinsic characteristics of that watercourse.

Authors: Robert Jehle And Walter Hödl

Abstract: During a long-term study (1987-1996) near Vienna (Austria), individual Danube crested newts ( Triturus dobrogicus) and common spadefoot toads (Pelobates fuscus) were registered by photographs of highly variable skin patterns, and the implantation of Passive Integrated Transponders (PIT tags). To test for potential detrimental effects of the electronic tags, we compared within-year (for P. fuscus) and between-year (for T. dobrogicus) recapture rates and body condition index (Cl) of individuals marked with the two alternative techniques. No significant negative effects of PIT tags on Cl and recapture rate could be demonstrated for either species. There was a decrease in body condition and recapture rates in the study years 1995 and 1996, but can be attributed to population trends rather than to the different marking methods. For recaptured T. dobrogicus a I 0.5% loss of PIT tags was observed.

Authors: Allison J. Abell

Abstract: Variation in sexual selection among populations and species has been suggested as an explanation for patterns of sexual size dimorphism. The strength of sexual selection on body size and other male traits was studied in a population of Sceloporus virgatus, a lizard in which females have a larger average size than males. Sexual selection on male size was found to be weak, with only the very smallest males having a mating disadvantage. This study provides tentative support for a sexual selection-fecundity selection trade off as an explanation for sexual size dimorphism in the genus Sceloporus, though further studies of the relationship between body size and reproductive success are needed

Authors: Susan G. Brown, Farrah Gomes And Frederick L. Miles

Abstract: The unisexuat gecko, Lepidodactylus lugubris, harbours fewer types of parasites and has lower prevalence of infection than does the bi sexual gecko, Hemidactylus frenatus, or its bisexual parental species. Because many diseases and parasites are transmitted through faeces, we conducted a series of experiments to examine whether or not L. lugubris had a greater tendency to avoid faecal matter than H.frenatus. The research found that both species defecated away from their daytime hiding places. The unisexual geckos, when given a choice, picked hiding places that were surrounded by clean rather than contaminated sphagnum moss, or places that were sprayed with distilled water rather than faecal solution. The bisexuals also displayed a tendency to pick hiding places surrounded by uncontaminated sphagnum moss, but, unlike the unisexuals, did not avoid faecal solution. Neither species avoided dried faecal matter. These data support our hypothesis that the unisexual gecko, L. lugubris, exhibits more parasite avoidance behaviours than the bisexual gecko, H. frenatus.