Comparative demography of sympatric populations of Lacerta vivipara and Lacerta agilis

Summary A mark-recapture study was carried out in sympatric populations of Lacerta agilis and Lacerta vivipara in the Netherlands from 1976 to 1982. In most years the age structure of both populations was pyramidal. For both species life expectation of females was higher and on average they did live longer. Hence the sex ratio for adults deviated significantly from 1.0 in favour of females. Maximum age for Lacerta vivipara was 8 years (female) and for Lacerta agilis 12 years (male). The density of both species fluctuated around 100/ha. The biomass of Lacerta agilis was twice that of Lacerta vivipara. In Lacerta vivipara the 3rd and 4th calendar year class supplied 78% of total net reproduction; in Lacerta agilis the 4th, 5th, and 6th calendar year classes supplied 68%. In both populations the population replacement rate was 2. Population turnover time was 4.83 years for Lacerta agilis and 2.81 for Lacerta vivipara. The life history strategy of the Lacerta vivipara population is compared with six other European Lacertavivipara populations.     

Geographic variation of life‐history traits in the sand lizard,Lacerta agilis: testing Darwin's fecundity‐advantage hypothesis

The fecundity‐advantage hypothesis (FAH) explains larger female size relative to male size as a correlated response to fecundity selection. We explored FAH by investigating geographic variation in female reproductive output and its relation to sexual size dimorphism (SSD) in Lacerta agilis, an oviparous lizard occupying a major part of temperate Eurasia. We analysed how sex‐specific body size and SSD are associated with two putative indicators of fecundity selection intensity (clutch size and the slope of the clutch size–female size relationship) and with two climatic variables throughout the species range and across two widespread evolutionary lineages. Variation within the lineages provides no support for FAH. In contrast, the divergence between the lineages is in line with FAH: the lineage with consistently female‐biased SSD (L. a. agilis) exhibits higher clutch size and steeper fecundity slope than the lineage with an inconsistent and variable SSD (L. a. exigua). L. a. agilis shows lower offspring size (egg mass, hatchling mass) and higher clutch mass relative to female mass than L. a. exigua, that is both possible ways to enhance offspring number are exerted. As the SSD difference is due to male size (smaller males in L. a. agilis), fecundity selection favouring larger females, together with viability selection for smaller size in both sexes, would explain the female‐biased SSD and reproductive characteristics of L. a. agilis. The pattern of intraspecific life‐history divergence in L. agilis is strikingly similar to that between oviparous and viviparous populations of a related species Zootoca vivipara. Evolutionary implications of this parallelism are discussed.     

Histochemical study of epididymal secretions in the lizard,Lacerta vvipara

Summary The epididymis of lizards elaborates voluminous secretory granules made of a central core and a peripheral vacuole which in the species Lacerta vivipara contain respectively an insoluble protein (protein H) and a soluble protein (protein L). After their discharge these secretions mix with spermatozoa. In order to detect the presence of carbohydrates in these secretions, lectins isolated from Canavalia ensiformis (con A) and from eleven other plants (lentil, soja, pea, gorse and several mushrooms), conjugated to fluorescein isothiocyanate, have been utilized in light-microscopic histochemical investigations of frozen sections from Lacerta vivipara epididymis. Whereas lectins having affinity for Lfucose, lactose, D-galactose and N-acetyl-D-galactosamine bound to central cores, lectins having affinity to D-glucose, N-acetylglucosamine and chitobiose bound to the peripheral vacuole. D-mannose or D-glucose seem to be present both in central cores and in peripheral vacuoles.     

Phylogenetic analysis of the Lacerta agilis subspecies complex

The Sand lizard Lacerta agilis inhabits a huge area across Eurasia with several subspecies. Nine subspecies are generally approved, L. a. agilis, L. a. argus, L. a. bosnica; L. a. chersonensis, L. a. exigua, L. a. grusinica, L. a. iorinensis, L. a. brevicaudata and L. a. boemica, but several more have been described. The emergence of this large number of subspecies is connected with the phylogeographic history of this species, defined by geographic and climatic processes. A study revealing phylogenetic relationships of this species was already conducted with a broad taxon sampling and coverage. However, the latter study was based solely on the cytochrome b gene and, furthermore, the Balkan Peninsula inhabited by the subspecies L. a. bosnica was underrepresented. This peninsula is a centre of European herpetofaunal endemism with high levels of phenotypic and genotypic variation. Therefore, the inclusion of the subspecies L. a. bosnica is important to clarify the overall view of the phylogenetic relations within the Lacerta agilis subspecies complex and to investigate the level of population differentiation within this highly diverse area. Thus, the aim of the present study was a more thorough analysis of the Balkan Peninsula with a broader taxon sampling. Furthermore, we extended the available datasets by adding the mitochondrial d-loop region and by further samples of different areas of the distribution range apart from the Balkan Peninsula. Our study reveals that the Balkan Peninsula is apparently inhabited by several differentiated lineages, whereby the Central Greek lineage might deserve subspecies status. Furthermore, the distribution area of the two subspecies L. a. agilis and L. a. argus should be revised, as the results of our study raise doubt about the commonly assumed distribution of both subspecies. As the most important outcome our results support that L. a. boemica deserves species status.     

Sex chromosome evolution in reptiles: divergence between two lizards long regarded as sister species,Lacerta vivipara andLacerta andreanskyi

Even if the common lizardLacerta vivipara and endemicLacerta andreanskyi from Moroccan Grand Atlas have the same mother species, the two species are definitely not closely related in present-day nature, whereL. vivipara stands at variance from all other lacertids in terms of cytogenetics. The use of replication banding, C-bands and R-bands has allowed for the identification of all chromosome pairs and two sex chromosomes inL. andreanskyi. Its karyotype is typical of Lacertidae. The W chromosome, characterized by late replication, is nevertheless of a type previously unknown in the family. The comparison of Z and W chromosomes by different methods of chromosome banding indicates little homology between them, if any. The replication study has shown that there is no dosage compensation for the Z chromosome in (homogametic) males. That genetic inactivation precedes chromosomal mutations in non-vivipara lacertid evolution of the odd sex chromosome is suggested.     

Supercooling,ice inoculation and freeze tolerance in the European common lizard,Lacerta vivipara

The European common lizard (Lacerta vivipara) is widely distributed throughout Eurasia and is one of the few Palaearctic reptiles occurring above the Arctic Circle. We investigated the cold-hardiness of L. vivipara from France which routinely encounter subzero temperatures within their shallow hibernation burrows. In the laboratory, cold-acclimated lizards exposed to subfreezing temperatures as low as -3.5°C could remain unfrozen (supercooled) for at least 3 weeks so long as their microenvironment was dry. In contrast, specimens cooled in contact with ambient ice crystals began to freeze within several hours. However, such susceptibility to inoculative freezing was not necessarily deleterious since L. vivipara readily tolerated the freezing of its tissues, with body surface temperatures as low as -3.0°C during trials lasting up to 3 days. Freezing survival was promoted by relatively low post-nucleation cooling rates (0.1°C·h^-1) and apparently was associated with an accumulation of the putative cryoprotectant, glucose. The cold-hardiness strategy of L. vivipara may depend on both supercooling and freeze tolerance capacities, since this combination would afford the greatest likelihood of surviving winter in its dynamic thermal and hydric microenvironment.Abbreviations bm body mass - SVL snout-vent length - T_b body surface temperature - T _c crystallization temperature     

Effect of water constraint on growth rate, activity and body temperature of yearling common lizard (Lacerta vivipara)

We investigated the effect of water constraints on yearling Lacerta vivipara, a widespread species of lizard inhabiting European peat bogs and heath land. We conducted a laboratory experiment to investigate plasticity of growth rate, activity level and preferred body temperature. We subjected individuals of two source habitats (dry vs humid) to two laboratory conditions of water supply resulting in different air relative humidity and water availability (high vs low). We observed that a low water supply induced a lower growth rate and lower activity level, suggesting that growth limitation is correlated with adaptive responses to avoid dehydration. However, individuals from the two habitats selected different body temperatures when restricted in water and showed different ratios between growth and activity. This suggests that there is population variability in phenotypic plasticity with respect to water availability in the habitat. Field observations conducted in six natural populations, classified into two groups (dry vs humid habitat) also suggest that growth rate in nature is constrained by water availability. Received: 8 June 1998 / Accepted: 16 November 1998     

Chemosystematische Untersuchungen zur Phylogenese der Sammelgattung Lacerta (Reptilia: Sauria: Lacertidae)

Chemosystematic investigations concerning the phylogeny of the collective genus Lacerta (Reptilia: Sauria: Lacertidae) Investigated the albumins from 31 species and subspecies of the genus Lacerta s.1. by means of the immunoloical techniue Micro-Complement-fixation. Dendrograms were computed by means of the ktch-MargJiash algorithm. Moreover the taxa of the Lacerta saxicola and the Lacerta danfordi comlexes were analyzed by electrophoresis concerning 14 genetic loci. The results were discussel together with karyological and genitalmorphological data so far known yielding the following relationships: Lacerta graeca shows a closer relationshi to the subgenus Podarcis as does the quite closely related species air L. dugesii and L. perspicikata. Lacerta Iaevis probabl is connected closely to Podarcis, too. Lacerta parva shows a closer relationship to the “small izards” than to the sub-genus Lacerta s. str. A clear decision concerning the position of the Lacerta danfordi complex according to chemosystematical data was not possible. It is isolated from the other species probably about as long as L. puma. Biochemical differences between its “species” are too small to confirm their taxonomical revalorisation by Eiselt and Schmidtler Within the Lacerta saxicola complex the investigated taxa show a close relationship. Lacerta praticola and L. derjugini were definitly assigned to this group.     

Competitive exclusion between insular Lacerta species (Sauria,Lacertidae)

Summary Competetive exclusion between Lacerta sicula and L. melisellensis characterizes the small islands of the Adriatic Sea.In 1958 and 1959 M. Radovanovié introduced Lacerta sicula or Lacerta melisellensis onto islands exclusively occupied by the other species. During the summer of 1971 follow-up observations were made on three of these islands, two of which completely lacked representatives of the introduced species. On the third island, the introduced species appears to be replacing the native form. Minor habitat differences permit coexistence, however the situation is dynamic and probably not at equilibrium. A reciprocal introduction involving the two species on the islands of Pod Kopite and Pod Mraru is announced.     

Identification of the linkage group of the Z sex chromosomes of the sand lizard (Lacerta agilis,Lacertidae) and elucidation of karyotype evolution in lacertid lizards

The sand lizard (Lacerta agilis, Lacertidae) has a chromosome number of 2n?=?38, with 17 pairs of acrocentric chromosomes, one pair of microchromosomes, a large acrocentric Z chromosome, and a micro-W chromosome. To investigate the process of karyotype evolution in L. agilis, we performed chromosome banding and fluorescent in situ hybridization for gene mapping and constructed a cytogenetic map with 86 functional genes. Chromosome banding revealed that the Z chromosome is the fifth largest chromosome. The cytogenetic map revealed homology of the L. agilis Z chromosome with chicken chromosomes 6 and 9. Comparison of the L. agilis cytogenetic map with those of four Toxicofera species with many microchromosomes (Elaphe quadrivirgata, Varanus salvator macromaculatus, Leiolepis reevesii rubritaeniata, and Anolis carolinensis) showed highly conserved linkage homology of L. agilis chromosomes (LAG) 1, 2, 3, 4, 5(Z), 7, 8, 9, and 10 with macrochromosomes and/or macrochromosome segments of the four Toxicofera species. Most of the genes located on the microchromosomes of Toxicofera were localized to LAG6, small acrocentric chromosomes (LAG11–18), and a microchromosome (LAG19) in L. agilis. These results suggest that the L. agilis karyotype resulted from frequent fusions of microchromosomes, which occurred in the ancestral karyotype of Toxicofera and led to the disappearance of microchromosomes and the appearance of many small macrochromosomes.     

Time matters. Locomotor behavior of <Emphasis Type="Italic">Lacerta viridis</Emphasis> and <Emphasis Type="Italic">Lacerta agilis</Emphasis> in an open field maze

Locomotor performance provides one of the key pieces of information regarding whole-organism function. Experiments encompassing behavioral data commonly endeavor to measure parameters such as burst speed, latency time, distance traveled, and other aspects of locomotion. Behavioral experiments can uncover an immense range of information, from the individual, interspecific, and intraspecific levels up to correlations with ecological factors and parameters from the ecosystem. Here, we explored the locomotor behavior of two lizard species, Lacerta viridis and Lacerta agilis, in an open field test (OFT). The main aim was to reveal changes in locomotion over time. Although we observed no time-related variation in L. agilis, we discovered significant changes in locomotor behavior over the course of the experiment in Lacerta viridis. Measured behavioral traits (resting time, total distance traveled, mean speed) showed significant changes across time in L. viridis, thus indicating the importance of time as a factor when conducting behavioral experiments. Moreover, we observed that in 10-min experimental session, the individuals have undergone different stages from freezing behavior, exploration, to habituation.     

Fluctuations in incubation temperature affect incubation duration but not morphology,locomotion and growth of hatchlings in the sand lizard Lacerta agilis (Lacertidae)

Li, H., Zhou, Z.‐S., Ding, G.‐H. and Ji, X. 2011. Fluctuations in incubation temperature affect incubation duration but not morphology, locomotion and growth of hatchlings in the sand lizard Lacerta agilis (Lacertidae). —Acta Zoologica (Stockholm) 00 : 1–8. Studies looking for potential effects of temperature and temperature fluctuations on phenotypic traits of reptile hatchlings have shown species variation, but have not always allowed a distinction between effects of fluctuation per se and temperature extremes themselves. To examine whether incubation temperature fluctuation has a key role in influencing the phenotype of offspring, we incubated eggs of the sand lizard Lacerta agilis at one of the four temperature regimes (27, 27 ± 2, 27 ± 4 and 27 ± 6 °C). We found that: (1) hatchlings incubated under the four temperature regimes did not differ from each other in any of the morphological and physiological traits examined; (2) interactions that included temperature treatment did not affect any trait examined; (3) the mean incubation length was longer in the 27 ± 6 °C treatment than in the other three treatments; and (4) female hatchlings were shorter in head length and width but longer in snout‐vent length as well as abdomen length than males derived from the same‐sized egg. Our data show that both the type and the magnitude of temperature variation can affect incubation length. We found no evidence for phenotypic divergence in responses to temperature fluctuations during incubation and therefore suggest that temperature variation does not affect the phenotype of hatchlings in L. agilis.     

Patterns of cranial ontogeny in lacertid lizards: morphological and allometric disparity

We explored the ontogenetic dynamics of the morphological and allometric disparity in the cranium shapes of twelve lacertid lizard species. The analysed species (Darevskia praticola, Dinarolacerta mosorensis, Iberolacerta horvathi, Lacerta agilis, L. trilineata, L. viridis, Podarcis erhardii, P. melisellensis, P. muralis, P. sicula, P. taurica and Zootoca vivipara) can be classified into different ecomorphs: terrestrial lizards that inhabit vegetated habitats (habitats with lush or sparse vegetation), saxicolous and shrub‐climbing lizards. We observed that there was an overall increase in the morphological disparity (MD) during the ontogeny of the lacertid lizards. The ventral cranium, which is involved in the mechanics of jaw movement and feeding, showed higher levels of MD, an ontogenetic shift in the morphospace planes and more variable allometric patterns than more conserved dorsal crania. With respect to ecology, the allometric trajectories of the shrub‐climbing species tended to cluster together, whereas the allometric trajectories of the saxicolous species were highly dispersed. Our results indicate that the ontogenetic patterns of morphological and allometric disparity in the lacertid lizards are modified by ecology and functional constraints and that the identical mechanisms that lead to intraspecific morphological variation also produce morphological divergence at higher taxonomic levels.     

How photoperiod influences body temperature selection in Lacerta viridis

Summary European green lizards, Lacerta viridis, show a distinct annual cycle in their day and nighttime selected body temperature (T _b) levels when monitored under natural photoperiod. The amplitude between daily photophase and scotophase temperatures varies throughout the year. Highest body temperatures with smallest day/night variation are selected from May through July. Throughout fall, the difference between day and nighttime selected T _b levels increases. Lizards inevitably enter a state of winter dormancy which terminates daily rhythmicity patterns. Under natural photoperiodic conditions, cessation of dormancy occurs spontaneously by mid-March, regardless whether high temperatures are available or not. Lacerta viridis respond to an artificial long photoperiod (16 h light, 8 h dark) at all times of the year with modifications in both diel patterns and levels of selected T _b to summer-like conditions. When, however, the natural photoperiod at different phases in the annual cycle is held constant for six to eight weeks, T _b selection of Lacerta viridis also remains stable at the level corresponding to the prevailing photoperiod. These results implicate that the photoperiod is a more prominent Zeitgeber for seasonal cueing of temperature selection than has been surmised in the past. Further, we suggest that the large variations recorded in daily T _b cycles do not imply that this lizard is an imprecise thermoregulator, but rather indicates an important integral process necessary for seasonal acclimatization.     

Thermal ecology of two sympatric skinks (Mabuya macrorhyncha and Mabuya agilis] in a Brazilian restinga habitat

Abstract In a restinga habitat of southeastern Brazil, we studied some aspects of the thermal biology of two sympatric skinks (Mabuya macrorhyncha and Mabuya agilis) with distinct microhabitat preferences. The two species did not differ significantly in their mean body temperature. Sex and body size did not explain body temperature variation within either species. The body temperature of both species is significantly affected by air temperature, but only that of M. agilis is significantly influenced by sand surface temperature, presumably due to its more terrestrial habit compared to M. macrorhyncha. We found no significant seasonal variation in body temperature for either species, although environmental temperatures varied seasonally, indicating that both species may be selecting an optimal range of body temperatures, possibly through behavioural thermoregulation.     

Buccal swabbing as a source of DNA from squamate reptiles

Buccal swabbing was compared with other tissues as a source of DNA for microsatellite genotyping from two squamate reptiles. For both species, the lizard Lacerta agilis and the snake Coronella austriaca, buccal swabbing proved more reliable than tissues including tail tips, toe clips and ventral scale clips.     

Density, social information, and space use in the common lizard (Lacerta vivipara)

Socially acquired information is widespread in the animal kingdom.Many individuals make behavioral decisions based on such socialinformation. In particular, individuals may decide to leaveor select their habitat based on social information. Few studieshave investigated the role of density-related information, apotential social cue about habitat quality in dispersal. Here,we tested for the possibility that the phenotype of intrudercommon lizards (Lacerta vivipara) may inadvertently carry informationabout their natal population density. We found that such informationuse is likely. The behavior of focal lizard was influenced bythe natal population density of the intruder it was interactingwith. This suggests that individuals may use the behavior ofothers to acquire appropriate information about surroundingsand to base spatial decisions on this information. Density-relatedinformation may then affect individual movement decisions andthus metapopulation dynamics.     

Isolation of new microsatellite loci from the Green Lizard (Lacerta viridis viridis)

Twelve new microsatellite loci were isolated from the Green Lizard (Lacerta viridis viridis). Primers for 28 loci were designed and 18 of these loci amplified well for 10 individuals of four populations. Twelve of these loci were further characterized for a population in Hungary. The results document the suitability of these identified loci for the characterization of the genetic diversity of the endangered species L. viridis viridis.     

Association of Mc1r variants with ecologically relevant phenotypes in the European ocellated lizard, Lacerta lepida

A comprehensive knowledge on the genetic basis of coloration is crucial to understand how new colour phenotypes arise and how they contribute to the emergence of new species. Variation in melanocortin‐1 receptor (Mc1r), a gene that has been reported as a target for repeated evolution in a wide range of vertebrate taxa, was assessed in European ocellated lizards (Lacerta lepida) to search for associations with melanin‐based colour phenotypes. Lacerta lepida subspecies’ distribution is associated with the three major bio‐climatic regions in the Iberian Peninsula. A nonconserved and derived substitution (T162I) was associated with the L. l. nevadensis phenotype (prevalence of brown scales). Another substitution (S172C) was associated with the presence of black scales in both L. l. lepida and L. l. iberica, but no mutations were found to be associated with the higher proportion of black in L. l. iberica. Extensive genotyping of Mc1r along the contact zone between L. l. nevadensis and L. l. lepida revealed low gene flow (only two hybrids detected). The implications of these findings are discussed in the context of previous knowledge about the evolutionary history of ocellated lizards.     

Energie-Bilanz eines Poikilothermen(Lacerta vivipara)

Zusammenfassung 1. Die Energiebilanz eines Tieres ist quantitativ im wesentlichen durch seinen Wärmehaushalt bestimmt oder mindestens in Wärmeäquivalenten ausdrückbar.2. Der Energiewechsel beruht auf zwei Hauptgruppen von Prozessen: Stoffwechselprozessen im Körperinneren und Wärmeaustausch zwischen Tierkörper und Umwelt.3. In beiden Gruppen treten regulative und nicht regulative Vorgänge auf. Die Regulation beim Wärmeaustausch zwischen Tierkörper und Umwelt beruht auf entsprechenden Verhaltensweisen.4. Der Unterschied zwischen Homoiothermen und Poikilothermen liegt nicht darin, daß die Regulationsmöglichkeit der Körpertemperatur nur den ersteren vorbehalten wäre (beide zeigen eine gewisse — und nur eine gewisse — Regulationsmöglichkeit), sondern darin, daß die Energiebilanz der Poikilothermen zum wesentlichen Teil durch den Wärmeaustausch mit der Umwelt beherrscht wird und daher auch die Regulation der Körpertemperatur wirksam nur durch Verhaltensweisen — die den Wärmeaustausch in die gewünschte Richtung lenken — erreicht werden kann.5. Aus der Beherrschung der Energiebilanz durch den Wärmeaustausch mit der Umwelt folgt auch, daß die Regulationskapazität der Poikilothermen weit geringer ist als die der Homoiothermen — obwohl natürlich auch deren Regulationskapazität begrenzt ist.6. Ein weiterer charakteristischer Unterschied zwischen Homoiothermen und Poikilothermen liegt darin, daß bei den ersteren die Überforderung der Temperaturregulation meist katastrophal endet, bei den letzteren hingegen eine normale Reaktion auslöst, nämlich den Übergang zu einer mehr oder weniger inaktiven, mindestens nicht vollaktiven Lebensweise. Aus verschiedenen Anzeichen läßt sich sogar schließen, daß Poikilotherme ein ständiges Leben im Aktivitätstemperaturbereich nicht ertragen könnten.7. FürLacerta vivipara wird eine möglichst komplette Energiebilanz gegeben.

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Energy balance of a poikilothermic animal(lacerta vivipara)

The main differences between homoiothermic and poikilothermic animals are considered on the basis of information from literature and results obtained by the author. It is not the occurrence of thermoregulation per se which constitutes the main differences between representatives of these two groups, but rather the manner in which this thermoregulation is performed. Whereas homoiothermic animals regulate by means of metabolic processes and changes in behaviour, poikilothermic animals employ the latter mechanism almost exclusively. InLacerta vivipara the close relationship between thermal balance and environmental factors is demonstrated on the basis of experimental results and calculations.