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Oxygen consumption levels and metabolic rate temperature curves of various lizard species from three different climatic regions were examined in relation to ambient temperature. The species used in this research were as follows: Anguis fragilis, Lacerta vivipara, Lacerta agilis (cool temperate species); Blanus cinereus, Podarcis hispanica, Podarcis lilfordi brauni, Podarcis lilfordi lilfordi, Podarcis muralis, Psammodromus algirus, Tarentola mauritanica (warm temperate species); Chalcides ocellatus, Acanthodactylus opheodurus, Acanthodactylus schmidti (desert species). A double chamber volumetric closed system was used to measure the resting oxygen consumption of the lizards. Acute oxygen consumption determinations were made, that is the lizards were not allowed to acclimate to the test temperatures. Interspecific differences in levels of resting oxygen consumption and in the characteristics of the metabolic rate temperature curves were examined in relation to methods of thermoregulation and in relation to the ecology of the respective species. Evidence for `temperature dependent shifts` and `low thermal dependence` was found in the metabolic rate temperature curves of some species. A diminishing Q10 at or below the voluntary body temperatures suggests some degree of metabolic homeostatsis and energy conservation.

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Dietary studies are essential to unravel the functioning of ecosystems and ultimately to understand biodiversity. This task, which at first may seem simple, becomes especially complex in those cases of omnivorous species with highly variable diets. In this regard, the emergence of next-generation DNA sequencing methodologies represents a powerful tool to address the problem. Here we implement a high-throughput metabarcoding strategy based on the analysis of four molecular markers aimed at sequencing both mitochondrial (animal prey) and chloroplast (diet plants) genome fragments from fecal samples of two lizard species endemic to the Balearic Archipelago (Podarcis lilfordi and P. pityusensis) obtained through non-invasive methods. The results allowed for the characterization of their diets with a high degree of taxonomic detail and have contributed a large number of new trophic records. The reported diets are based mainly on the consumption of arthropods, mollusks and plants from a diversity of taxonomic orders, as well as carrion and marine subsidies. Our analyses also reveal inter- and intra-specific differences both in terms of seasonality and geographical distribution of the sampled lizard populations. These molecular findings provide new insights into the trophic interactions of these threatened endemic lizards in their unique and isolated ecosystems.

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Gut microbial communities provide essential functions to their hosts and are known to influence both their ecology and evolution. However, our knowledge of these complex associations is still very limited in reptiles. Here we report the 16S rRNA gene faecal microbiota profiles of two lizard species endemic to the Balearic archipelago (Podarcis lilfordi and P. pityusensis), encompassing their allopatric range of distribution through a noninvasive sampling, as an alternative to previ- ous studies that implied killing specimens of these IUCN endangered and near-threatened species, respectively. Both lizard species showed a faecal microbiome composition consistent with their omnivorous trophic ecology, with a high representa- tion of cellulolytic bacteria taxa. We also identified species-specific core microbiota signatures and retrieved lizard species, islet ascription, and seasonality as the main factors in explaining bacterial community composition. The different Balearic Podarcis populations are characterised by harbouring a high proportion of unique bacterial taxa, thus reinforcing their view as unique and divergent evolutionary entities.

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The sensory innervation of the pineal organ of adult Lacerta viridis has been investigated. Some specimens of Lacerta muralis lillfordi were also used. In the pineal epithelium, a small number of nerve cell pericarya of a sensory type are present. They lie either solitary or in small clusters close to the basement membrane. The axons originating from the nerve cell bodies, i. e. the pineal sensory nerve fibers, first course in the intraepithelial nerve fiber layer which is only locally present and contains a restricted number of unmyelinated fibers. In Lacerta viridis, the pineal fibers generally leave the epithelium at the proximal part of the organ proper. They then form small bundles which run along the outer surface of the basement membrane in the leptomeningeal connective tissue covering. At the proximal end of the pineal stalk the single bundles assemble constituting the pineal nerve. In Lacerta muralis the fibers leave the pineal epithelium at the proximal end of the stalk running farther down within the epithelium. Many fibers become myelinated after leaving the pineal epithelium. The pineal nerve runs ventralward in the midplane just caudal to the habenular commissure to which no fibers are given off. Continuing their ventralward course between the habenular commissure and the rostral end of the posterior commissure which is traversed by some of them, the pineal fibers reach the dorsal border of the subcommissural organ. Small separate aberrant pineal bundles traverse the posterior commissure at various more caudal levels. Having reached the dorsal border of the subcommissural organ, part of the pineal fibers continue their ventralward course directly running along the lateral sides of this organ to reach the periventricular nerve fiber layer lateral and ventral to it. A restricted number of fibers first turns in a caudal direction running between the base of the posterior commissure and the base of the subcommissural organ before turning ventralward to reach the periventricular layer. Most probably, pineal fibers do neither join the posterior commissural system nor innervate the subcommissural organ. Once having reached the periventricular layer, some pineal fibers curve in a rostral direction while others, before doing so, send a collateral in a caudal direction. Both, the main fibers and the collaterals, contribute to the formation of the periventricular layer. The sites of termination of the pineal fibers could not be ascertained. From the presence of intraepithelial sensory nerve cell bodies and from literature data on the ultrastructure of pineal neurosensory cells it is concluded that the adult pineal organ of Lacerta has a, although rudimentary, (photo)sensory function. The demonstration by our guest-worker Dr. W. B. Quay, of the intraepithelial presence of a tryptamine compound, probably serotonin, points, moreover, to a secretory function of this organ. In adult Lacerta a well-developed parietal nerve connects the parietal eye with the left lateral habenular nucleus. It traverses the habenular commissure.

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In this article an introduction is given on the geological history leading to the separation of Podarcis lilfordi (GÜNTHER, 1874) and Podarcis pityusensis (BOSCÁ, 1883) as separate species, as well as a Holocene sea level rise model which combined with bathymetric data leads to an estimation of recent divergence time in populations of the Balearic lizards.

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New data on estimated divergence times of the populations of lacertid lizards in the Balearic Islands are provided in this second update of the October 2011 article: Estimating recent divergence time in populations of Podarcis lilfordi (GÜNTHER, 1874) and Podarcis pityusensis (BOSCÁ, 1883) (VAN DEN BERG 2011), which received its first update May 2012. In most cases better estimations of divergence times were available by using the NAVIONICS SonarCharts™webapp.

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Extensive studie on the natural values of Illa de l`Aire and proposals for conservation.

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1. Ecological energetics and water fluxes were compared between populations of the lacertid lizard Podarcis lilfordi from the Menorcan islets of Aire (Illa de l`Aire) and Nitge (Illa des Porros) (Balearic Islands. Spain) during a non-reproductive summer period using the doubly labelled water technique. 2. Lizards from Aire (Illa de l`Aire) were larger than those from Nitge (Illa des Porros) (9.6±0.58 g vs 5.1±0.38 g, respectively) and consequently had higher field metabolic rates (FMR) (1.739±0.151 kJ daysup-1/sup vs 1.255±0.977 kJ daysup-1/sup). 3. FMR were lower in the Aire (Illa de l`Aire) population, when the effects of the differing body masses were removed. 4. There were substantial differences in food availabilities between the two islets and this was reflected in strong dietary differences between the lizard populations. 5. Feeding constraints were potentially lower in Aire (Illa de l`Aire) owing to (a) greater arthropod availability, (b) greater abundance of edible flowers, and (c) lower lizard density. 6. We suggest that a reduction in constraints on food intake could enable more efficient foraging by Aire (Illa de l`Aire) lizards, and so explain their lower mass-independent FMR. 7. Although omnivory in Aire (Illa de l`Aire) lizards appeared to increase the amount of preformed water obtained from the food, no differences in mass-independent water flux were found, probably because drinking represented the primary source of water intake.

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Phylogenetic relationships and timings of major cladogenesis events are investigated in the Balearic Island lizards Podarcis lilfordi and Podarcis pityusensis using 2675 bp of mitochondrial and nuclear DNA sequences. Partitioned Bayesian and Maximum Parsimony analyses provided a well-resolved phylogeny with high node-support values. Bayesian MCMC estimation of node dates was investigated by comparing means of posterior distributions from different subsets of the sequence against the most robust analysis which used multiple partitions and allowed for rate heterogeneity among branches under a rate-drift model. Evolutionary rates were systematically underestimated and thus divergence times overestimated when sequences containing lower numbers of variable sites were used (based on ingroup node constraints). The following analyses allowed the best recovery of node times under the constant-rate (i.e., perfect clock) model: (i) all cytochrome b sequence (partitioned by codon position), (ii) cytochrome b (codon position 3 alone), (iii) NADH dehydrogenase (subunits 1 and 2; partitioned by codon position), (iv) cytochrome b and NADH dehydrogenase sequence together (six gene–codon partitions), (v) all unpartitioned sequence, (vi) a full multipartition analysis (nine partitions). Of these, only (iv) and (vi) performed well under the rate-drift model. These findings have significant implications for dating of recent divergence times in other taxa. The earliest P. lilfordi cladogenesis event (divergence of Menorcan populations), occurred before the end of the Pliocene, some 2.6 Ma. Subsequent events led to a West Mallorcan lineage (2.0 Ma ago), followed 1.2 Ma ago by divergence of populations from the southern part of the Cabrera archipelago from a widely-distributed group from north Cabrera, northern and southern Mallorcan islets. Divergence within P. pityusensis is more recent with the main Ibiza and Formentera clades sharing a common ancestor at about 1.0 Ma ago. Climatic and sea level changes are likely to have initiated cladogenesis, with lineages making secondary contact during periodic landbridge formation. This oscillating cross-archipelago pattern in which ancient divergence is followed by repeated contact resembles that seen between East-West refugia populations from mainland Europe.

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Escape theory predicts that flight initiation distance (FID = predator-prey distance when escape begins) increases as predation risk increases. We tested effects of variation of approach speed and directness, predator persistence, concealment, and weather conditions on FID in the Balearic lizard (Podarcis lilfordi) by ourselves simulating predators. We examined effects of directness of approach on probability of fleeing and of repeated approach on entering refuge and distance fled. As predicted, FID was greater for faster approach speed, more direct approach, during second than first approaches, and when lizards were exposed than partially concealed. Other effects of directness of approach and repeated approach also were as predicted by greater assessed risk by the lizards. The proportion of individuals that fled was greater for direct than indirect approaches. The proportion of lizards that entered refuges and distance fled were greater during the second of two successive approaches. Effects of weather on FID were complex. FID was shortest in the warmest conditions with no noticeable wind, when lizards were active. Lizards were inactive and basked in the other conditions. FID was longest at 20°C without wind, and intermediate FID occurred at 18°C in windy conditions. We present hypotheses for weather effects. Tests are needed to unravel effects of temperature and wind speed. All predictions of escape theory for simple risk factors, i.e., all except than weather conditions, were confirmed. Escape theory successfully predicts FID for these risks in P. lilfordi, other lacertids, and more broadly, in ecologically and taxonomically diverse lizards.

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Prey often exhibit reduced escape behavior on islands where predators are absent or scarce. Models of escape and refuge use predict that prey from populations having lower predation pressure have shortened flight initiation distance (FID; distance between a predator and a prey when escape begins), reduced distance fled and tendency to enter refuge, and shortened hiding time before emerging from refuge. By ourselves simulating approaching predators, we tested these predictions for two populations of the Balearic lizard, Podarcis lilfordi (Müller, 1927), on the islets of Rei (higher predation pressure) and Aire (lower) adjacent to Menorca. FID, distance fled, and hiding time were shorter and probability of entering refuge was lower on Aire than on Rei, confirming all predictions. All effect sizes were large, indicating major differences in antipredatory behavior between islets. These findings are consistent with data for other lizards on FID and limited data on distance fled and refuge entry. The effect of predation pressure on hiding time is a novel finding. Our results and those of previous studies suggest that relaxation of predation pressure leads to reduced natural selection for maintenance of antipredatory behavior at all stages of predator–prey interactions over a relatively short time span.

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Although squamate reptiles are known to locate conspecifics by scent-trailing and to locate and identify prey by tongue-flicking substrates, an ability to locate food using only airborne cues has previously only been suspected based on observations that dead animals can be used as bait for Komodo dragons and that some nocturnal geckos aggregate on flowers. We conducted a simple field test of the ability of the omnivorous lizard Podarcis lilfordi from Aire islet (Illa de l`Aire) to find fruit hidden under opaque cups. When a board having two identical cups spaced 1 m apart, one empty and the other hiding a freshly cut piece of apricot, was placed in the habitat, lizards first contacted the cup hiding fruit at well above chance frequency. Upon contact with a cup, lizards were significantly more likely to stay next to the cup, tongue-flick at high rates, climb the cup, and attempt to bite the cup if it hid a piece of apricot. The ability to follow a concentration gradient of airborne volatile chemicals to its source is very likely mediated by olfaction, but participation by or primacy of vomerolfaction cannot be excluded.

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Specialist predators may respond strongly to sensory cues from preferred prey, but responses by generalist predators, although predicted to be less specific, are poorly known. Among squamate reptiles, diet and strength of response to chemical prey cues covary geographically in snakes that are specialist predators. There have been no previous studies of correspondence between diet and chemosensory response in lizards that are prey generalists. Actively foraging lizards discriminate between prey chemicals and control substances. It has been speculated that differential responses among prey species are unlikely in typical species that are dietary generalists. We examined this relationship in Podarcis lilfordi, an omnivorous lacertid that consumes a wide variety of animal prey. In experiments in which chemical stimuli were presented on cotton swabs, lizards responded more strongly to chemicals from a broad spectrum of prey types than to deionized water, an odorless control. These findings plus previous data showing that P. lilfordi is capable of prey chemical discrimination suggest that P. lilfordi can identify a wide range of potential prey using chemical cues. However, there was no evidence of differential response to stimuli among prey species, even in comparisons of prey included in the natural diet and potential prey not in the diet. The results, although limited to a single species, are consistent with the hypothesis that lizard species that are prey generalists do not exhibit the differential response strengths to chemical prey cues observed in snakes that have more specialized diets.

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Here we report the findings of field experiments on kleptoparasitism in the Balearic lizard, Podarcis lilfordi, from Aire, an islet offshore from Menorca.

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Optimal escape theory predicts that prey permit closer approach by predators when fleeing is more costly, but does not predict other aspects of escape such as distance fled or the likelihood of returning to the initial site in the presence or absence of a resource such as food. Because a lizard preparing to feed may lose the feeding opportunity, optimal escape theory predicts that the lizard should allow a predator to approach closer before fleeing when a stationary food source is present than in its absence. In addition, we predicted that when a predator was nearby, lizards would flee a shorter distance and return more often when food was present than absent. We presented adult males of the omnivorous Balearic lizard, Podarcis lilfordi, with a tethered piece of pear or a pebble of similar size and shape. One of us approached a lizard in a standardized manner, stopping and remaining still when the lizard fled. The other investigator recorded escape and return behaviors. Lizards in the presence of food permitted closer approach before fleeing, fled a substantially shorter distance, and were far more likely to return to the site of stimulus presentation than when a pebble was presented. These findings suggest that prey may alter several aspects of escape behavior to reduce costs due to lost opportunities, and present a likelihood that interspecific variation exists in the combination of aspects of antipredatory behavior that are modified.

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During encounters with predators, prey must balance the degree of risk against the loss of fitness-enhancing benefits such as feeding and social activities. Most studies of tradeoffs between risk and cost of escaping have measured flight initiation distance and time to emerge from refuge, for which theory provides robustly supported predictions. Tradeoffs involving other aspects of encounters, including distance fled and time between escape and return to a food source, have received little theoretical or empirical attention. By adapting models of flight initiation distance and time between entry into refuge and emergence, we predict effects of predation risk and cost on distance fled and time to return to a source of benefit after fleeing. Acting as simulated predators that approached at a fixed speed, we conducted an experimental field study to test the hypotheses that flight initiation distance, distance fled, and time to return to food by Balearic lizards (Podarcis lilfordi) decrease with the presence and amount of insect food. Predictions of the models were strongly supported, including those for distance fled and return time, but predictions for other cost factors and predation risk factors remain to be tested. The study site was conducted on Aire (Illa de l`Aire), an islet off the coast of Menorca, Balearic Islands, Spain in early May 2005 on sunny days between 8:45 AM and 3:50 PM when lizards were active and foraging. Aire is an ideal site for studies of tradeoffs between antipredatory behavior and foraging because the exceedingly high population density of the Aire population facilitates data collection.

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The number of simultaneously attacking simulated predators and their approach speeds and angles affected escape trajectories and flight initiation distance in Balearic Lizards (Podarcis lilfordi). Our findings confirmed predictions prey flee in directions maximizing distance from predator(s). During slow approaches, escape angle was 45° when approached by two predators at right angles and 90° when approached from opposite directions. Escape at close to 45° by lizards approached at slower speed by a single predator supports the hypothesis that prey use escape trajectories allowing them to visually monitor predators. Flight angles were closer to being straight away from a predator during faster approaches, suggesting that distance maximization may be more important than monitoring predator position when risk is great. When predators approached from opposite directions, flight angle shifted away from the faster predator, suggesting that lizards may have equalized risk from both predators based on positions and speeds. Flight initiation distance was greater for approach by predators side by side than by one only during faster approaches, suggesting that risk is a joint function of predator number and speed. Flight initiation distance was greater when predators approached at right angles than side by side, perhaps because of difficulty of monitoring multiple predators in different locations. Distance fled did not differ among treatments and may have been affected by distance to refuge. Thus, Balearic Lizards adjusted flight initiation distance and escape trajectories in ways that enhanced their abilities to avoid predation during simultaneous approaches by two predators.

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Foraging modes were described originally for insectivorous lizards, but many species are omnivorous or herbivorous. Because seeking and consuming plants might alter foraging, we studied foraging by the omnivorous Podarcis lilfordi at two sites: one where lizards licked nectar from flowers of Euphorbia paralias and the other where they sought insects. Movements per minute (MPM) did not differ among groups. Proportion of time spent moving (PTM) was similar in lizards that licked flowers and those that did not. Average speed (AS) was slower, and speed while moving (MS) was faster when foraging for nectar than for insects. Lizards foraging for nectar did not eat insects; those foraging for insects frequently ate them. For lizards foraging for prey, MPM increased as PTM, AS, and capture attempts increased and as PTM decreased. PTM increased as AS and capture attempts increased and decreased as MS increased. AS increased as MS increased. For lizards that licked, proportion of time licking (PTL) was unrelated to MPM, PTM, or AS but increased marginally as MS increased. Lizards foraging for nectar retained the PTM of lizards foraging for prey, but added a large PTL. The ancestral active foraging mode has been retained for hunting insects but modified to search for and lick nectar. While foraging for nectar, lizards greatly reduce attacks on insects, suggesting that, at a given time, an individual forages exclusively for nectar or prey. Reduced predation pressure on islands may have freed lizards to expand the diet by reducing risk during intervals exposed to view while climbing plants and licking nectar.

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Many lizards can identify food using chemical cues, but very little is known about the chemical constituents used for this purpose. We experimentally investigated responses to several lipid stimuli by the omnivorous lacertid lizard Podarcis lilfordi, which had been shown previously to be capable of identifying prey using only chemical cues and to respond to pork fat by tongue-flicking and biting. In 60-s trials in which stimuli were presented on cotton swabs, the lizards responded very strongly to pure pork fat and to oleic acid, but not to cholesterol or glycerol. Latency to bite swabs, the number of individuals that bit swabs, and the tongue-flick attack score, TFAS(R), which combines effects of tongue-flicks and bites, showed stronger responses to fat than to cholesterol, glycerol, and distilled water but did not differ significantly from responses to oleic acid. Several lines of evidence show that oleic acid elicited strong chemosensory and feeding responses. For individuals that did not bite, the number of tongue-flicks was significantly greater for oleic acid than for distilled water or glycerol, and nearly so for cholesterol. Latency to bite was significantly shorter for oleic acid than for distilled water, and TFAS(R) was significantly greater for oleic acid than for distilled water and glycerol. In combination with pilot data indicating no strong response to the waxy, saturated palmitic acid, these findings suggest that oleic acid in particular and probably other unsaturated fatty acids found in animal fat contribute strongly to the food-related responses to lipids.

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Costly anti-predatory defences are used in ecological time and maintained in evolutionary time by natural selection favouring individuals that survive through their use. Autotomy of expendable body parts is a striking example of a defence having multiple substantial costs, including loss of ability to use the same defence, loss of energy, and decreased growth, reproductive success and survival following autotomy, plus the energetic cost of replacing the lost body part in species capable of regenerating them. Our study shows that autotomy in the lacertid lizard Podarcis lilfordi reduces sprint speed, indicating decreased capacity to escape as well as the loss of energy. Autotomy carries substantial cost, and thus should be avoided except as a last resort. Ease of autotomy and post-autotomic movements were studied in three populations of lacertid lizards. Two were islet populations of Podarcis lilfordi from Aire (Illa de l`Aire) (lowest predation pressure) and Colom (Illa d`en Colom) (intermediate predation pressure) off Minorca. The third was a mainland population of Podarcis hispanica, a closely related species from the mainland of the Iberian Peninsula where predation pressure is higher than on the islets. As predicted, a suite of autotomic traits increases the effectiveness of autotomy as a defence as predation pressure increases. With increasing predation pressure, the frequency of voluntary autotomy increases, latency to autotomy decreases, pressure on the tail needed to induce autotomy decreases, vigour of post-autotomic tail movements increases, and distance moved by the shed tail increases. Additional changes that might be related to predation pressure, but could have other causes, are the presence of tail coloration contrasting with body coloration except under the lowest predation pressure (Aire) and longer tails in the mainland species P. hispanica. Correspondence between predation pressure and the suite of autotomic traits suggests that autotomy is an important defence that responds to natural selection. Comparative data are needed to establish the generality of relationships suggested in our study of only three populations.

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An ability to detect plant toxins and thereby avoid eating chemically defended plants would be very beneficial for omnivorous and herbivorous lizards. We studied the ability of the omnivorous Podarcis lilfordi to detect compounds belonging to three classes of common plant toxins, as well as responses indicating aversion. Solutions of the alkaloid quinine, saponin, and the phenolic coumarin, as well as distilled water (odorless control), were presented to lizards on cotton swabs. The lizards detected all three toxins as indicated by significantly decreased tongue-flick rates and tongue-flick attack scores in comparison with distilled water. Several other variables revealed aversion to saponin, including a low number of individuals that bit swabs, avoidance of swabs after tongue-flicking, performance after tongue-flicking the swab of repeated short-excursion tongue-flicks that were directed away from the swab and did not contact any substrate, failure to respond at all in the next trial, and wiping the snout on the floor of the terrarium. Reasons for apparent differences in tongue-flicking behavior between P. lilfordi and two other omnivorous lizard species are discussed. We also showed experimentally that saponin depresses the tongueflick rate in the omnivorous Bonaire whiptail lizard, Cnemidophorus murinus. Tongue-flicking enables at least one lizard species to detect specific chemicals representing three major classes of plant toxins. It is hypothesized that this ability is a widespread adaptation to reduce ingestion of plant toxins.

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Comparative analyses were carried out about the variability of the pileal shields of different species belonging to the family Lacertidae. The results of the comparisons have been evaluated in respect to the phylogenetical relationships existing between the different genera and species of the family.

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The aim of this study is to assess the health status of different populations of P. lilfordi, an endemic lizard of the Balearic Islands. The health status and potential environmental stress to which these populations are subject estimaatendiendo four independent indicators, putting both to test its reliability and searching for the possible relationship between them. These four indicators are: the so-called state of condition of individuals, the parasite load, immune response and the degree of fluctuating asymmetry observed in bilateral characters. Also, relationships are established with adaptive responses in terms of features of behavioral ecology, including: strategies to secure food, defense capabilities and tactics of escape from predators.

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The spatial distribution of a population of lizards is influenced by the distribution of resources and the individuals’ skills to gain access to them. On several Mediterranean islands with food scarcity and unpredictable resource availability, some resources can be extremely important during some periods of the year, as, e.g., the dead horse arum, Dracunculus muscivorus, on Aire Island, Spain. In this study, we analysed parasite infestation in an endemic lizard, Podarcis lilfordi, in relation to the distribution of D. muscivorus during spring. We found a higher prevalence of parasitism in males from a central area where the plant was significantly more abundant. Also, in this area, males were more abundant and larger than in two areas with lower plant densities. Moreover, overall differences appeared in the intensity of infection, which was higher in individuals from the central area, and we found a relationship between body size and parasite load, with more infected cells in larger individuals. Spatial distribution of individuals due to differential availabilities of D. muscivorus is proposed as an explanation for the observed differences.

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In animals, developmental stability is frequently assessed by the level of fluctuating asymmetry. Several environmental and genetic stress factors can increase the developmental instability in a population. Anyhow, the use of fluctuating asymmetry as a measurement of developmental instability and its relationship to other measurements of genetic and environmental stress, remain controversial. We studied this subject in the Balearic lizard, Podarcis lilfordi, and examined four populations inhabiting different coastal islets of Minorca (Balearic Islands, Spain). These populations show clear ecological and genetic differences that allowed us to study factors potentially determining the level of fluctuating asymmetry. We examined the following predictions: (1) fluctuating asymmetry will increase on smaller islands; (2) fluctuating asymmetry will increase on islands with a higher lizard density; (3) fluctuating asymmetry will increase on islands with more heavily parasitized lizards; and (4) populations with higher inbreeding levels would be more susceptible to environmental stress. Our results would partially support the fourth prediction of a higher fluctuating asymmetry in populations with lower genetic variability and, consequently, a higher inbreeding level. Probably, other environmental factors modulate this relationship.

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Many wild populations of lizards in the Mediterranean Basin inhabit small islands frequently visited by humans. Reptiles respond to humans as potential predators by escaping to refuges or by increasing antipredator behaviours which lead to a loss of body condition and may have important consequences for fitness. We assessed effects of human pressure on parasitism and body condition of the endangered insular lizard Podarcis lilfordi in Aire Island (Balearic Islands, Spain). Two areas differing in the number of visitors were compared at different seasons: spring, with almost no human pressure, and summer, when the major bulk of visitors arrive. Compared across seasons, the lizards from areas frequented by humans suffered a greater loss of body condition and showed a less parasitism reduction compared to individuals from the undisturbed area. Therefore, human disturbance seems to have deleterious effects on body condition and other fitness-related drivers, as parasitism. Results evidence important consequences of tourism for short- and long-term fitness of individuals and should be considered when designing conservation plans or management strategies.

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Economic escape models predict escape decisions of prey which are approached by predators. Flight initiation distance (FID, predator–prey distance when prey begins to flee) and distance fled (DF) are major variables used to characterize escape responses. In optimal escape theory, FID increases as cost of not fleeing also increases. Moreover, FID decreases as cost of fleeing increases, due to lost opportunities to perform activities that may increase fitness. Finally, FID further increases as the prey`s fitness increases. Some factors, including parasitism, may affect more than one of these predictors of FID. Initially, parasitized prey may have lower fitness as well as impaired locomotor ability, which would avoid predation and/or reduce their foraging ability, further decreasing the opportunity of fleeing. For example, if parasites decrease body condition, prey fitness is reduced and escape ability may be impaired. Hence, the overall influence of parasitism on FID is difficult to predict. We examined relationships between escape decisions and different traits: parasite load, body size and body condition in the Balearic lizard, Podarcis lilfordi. Lizards that showed higher haemogregarines load had longer FID and shorter DF. Although results did not confirm our initial predictions made on the basis of optimal escape theory, our findings suggest that parasites can alter several aspects of escape behaviour in a complex way.

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A survey about the helminthfauna of Podarcis lilfordi (Günther, 1874) (Sauria, Lacertidae) in the Gimnesic Islands (Balearic Islands, Spain) has been carried out. Eleven species of helminths were found, two Digenea, eight Nematoda and one Acanthocephala. Data of prevalence of each helminth species are indicated. The nematodes Skrjabinodon medinae and Spauligodon cabrerae show the highest values of prevalence and abundance. Host-parasite relationships are discussed, and the absence of cestodes is pointed out.

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Many lizards use femoral gland secretions in intraspecific communication. Although there is a consistent interspecific variation in chemical composition of secretions, considerable variation is also often found between populations, which may affect conspecifc recognition and lead to speciation processes. Balearic lizards (Podarcis lilfordi) are currently distributed only in several isolated islets offshore of the main islands with different environmental conditions (vegetation, diet, density of population, etc). Also, there is a high genetic variability between populations. We examined whether there was a similar variation in the composition of the femoral secretions of male lizards, and which could be the causes of such variation. By using GC–MS analyses, we found 75 lipophilic compounds in femoral gland secretions of male P. lilfordi from three representative island populations. Main compounds were steroids (94.4%), mainly cholesterol, but we also found alkanes, ketones, waxy esters, squalene, carboxylic acids and their ethyl esters, alcohols and other minor compounds. However, there were clear differences between populations with respect to the number and relative proportions of compounds. Using the patterns of presence and abundance of compounds in secretions it is possible to predict the population of origin of a lizard. We discuss how these differences could be explained considering genetic and environmental differences between populations.

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Three subspecies of P. lilfordi were observed in their natural habitats. Some fieldnotes and notes on behaviour in captivity are given. Finally it is stated that these three subspecies appear not to be endangered.

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Selection of thermally suitable microhabitats plays an important role in the thermoregulation of ectotherms. We studied microhabitat preferences in two populations of the Balearic lizard, Podarcis lilfordi, that live on two coastal islets of Menorca (Balearic Islands, Spain: Aire and Colom). To assess the roles of different microclimatic traits driving lizards’ decisions, we employed a case/control design. We measured microclimate variables in locations used by lizards (cases) and in paired random unused locations (controls). By comparing paired cases vs controls, we prevent spatial and temporal variation of environmental conditions. In order to test if microhabitat selection depends on thermoregulation requirements, we studied lizards in three situations: (1) ‘cold’, when body temperatures (Tb) of lizards were below their preferred temperature range (PTR), (2) ‘optimal’, when Tb were within the PTR, and (3) ‘warm’, when Tb exceeded the PTR. Substrate temperature was the main abiotic trait that determined microhabitat preferences of P. lilfordi, sometimes in conjunction with air temperature, while wind speed and humidity were not significant. ‘Cold’ lizards selected warmer microhabitats than the mean, but only on Colom islet. Notably, ‘optimal’ lizards also preferred microhabitats that were warmer than their surroundings, and ‘warm’ lizards did not select cold microhabitats in order to cool themselves, but rather acted randomly regarding temperature, wind and humidity. These results for ‘optimal’ and ‘warm’ lizards were consistent for both islets. We also studied the beginning and end of lizards’ diel activity. We found that lizards on Aire were active for approximately one hour more per day than lizards on Colom, which might be related to differences in melanism. However, activity started at an air temperature of approximately 17–19°C and finished at approximately the same temperature on both islets.

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Caudal autotomy is an effective antipredator strategy widespread among lizards. The shed tail thrashes vigorously for long periods to distract the predator and facilitate the lizard`s escape. This movement is maintained by energy supplied by the anaerobic conversion of glycogen into lactate. It has been suggested that lactate accumulation serves as an index for the vigor of tail thrashing. We made three predictions: (1) tail loss frequency should be higher under heavier predation regime, (2) the duration of postautotomy tail movement should be extended in populations under heavy predation pressure as an adaptation to the higher risk and the increased need for defense, and (3) as result, lactate in these tail tissues should be concentrated at higher levels. To eliminate the impact of phylogeny and environmental factors on the interpretation of our result, we focused exclusively on one species, the Balearic lizard (Podarcis lilfordi). We studied three populations, Colom (Illa d`en Colom), Aire (Illa de l`Aire), and Sargantana (Illa Sargantana), under different predation pressure but sharing the same climatic conditions. We found no differences among the studied populations either in postautotomy duration of tail movement or in levels of final lactate accumulation while autotomy frequency was higher where predation pressure was more intense. Tail loss effectiveness is directly influenced by the level of predation, while secondary features of the trait appear to remain independent from the impact of environment.

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The ecological characteristics of three coastal islets of Menorca (Balearic Islands) were compared, as well as reproductive variables of their Balearic Lizard populations. Islets under analysis, Aire (Illa de l`Aire), Rey (Illa del Rei) and Colom (Illa d`en Colom), showed differences in trophic availability, human and predator presence, surface and geological age. Population density and female body size were different in the three populations. Howeevr, even under different selective pressures, populations didn`t show differences in clutch size, eggs size and mass, or reproductive effort. Wefound a lengthy reproductive period (May to July) and multiple cutches (2 annual clutches). Three islets had a mean clutch size of 2.12 ± 0.13 eggs (ranging between one and four eggs per clutch). We did not detect a relation between clutch size and female body size. We saw a elationship between length or mass, and the clutch size.

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A more generalized diet, as well as higher plant consumption by lizards in islands with poor trophic resources, has been widely documented. From some years ago, it has been ob- served individuals of the Balearic lizard, Podarcis lilfordi (Lacertidae), climbing to Carlina corym- bosa (Asteraceae) in Aire Island (Menorca, Balearic Islands, Spain) and foraging on their owers during the blooming period, from early July to late August. Through focal observations, we have studied the foraging behaviour of P. lilfordi on C. corymbosa. We obtained fourteen variables, from which we de ned three groups according to the information they provide: movements and foraging strategy, use of C. corymbosa as a trophic resource and foraging behaviour of P. lilfordi on that plant species. The analysis of these variables shows that P. lilfordi is a widely forager that employs a mixed strategy of licking and pulling up Carlina owers. This behaviour is probably due to a low production and/or a dif cult availability of nectar. Some behavioural traits are similar to those observed while foraging on carcasses. We also studied, during the same period, the diet of P. lilfordi through the analysis of faecal samples. We observed that the consumption of plant ele- ments is important during July and August, and that C. corymbosa is an important resource in the areas of the island where it is present.

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Even in solitary foragers, conspecifics can provide reliable information about food location. The insular lizard Podarcis lilfordi is a solitary species with high population densities that sometimes aggregate around rich food patches. Its diet includes novel and unpredictable resources, such as carcasses or plants, whose exploitation quickly became widespread among the population. We tested the use of social information by lizards through some field experiments in which they had to choose one of the two pieces of fruit. Probably due to local enhancement, lizards preferred to feed on the piece of fruit where conspecifics or lizard-shaped models were already present. Conspecifics’ behaviour, but also their mere presence, seems to be a valuable source of information to decide where to feed. Lizards also showed a strong attraction to conspecifics, even in the absence of food. Maybe the presence of a group is interpreted as an indirect cue for the presence of food. The group size was not important to females, but males had a significantly higher attraction towards groups with three conspecifics. We discuss some characteristics of P. lilfordi at Aire Island that can explain the development of the observed social foraging, as well as their possible consequences.

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Aims: To characterize the genetic and morphological diversification of the endan- gered Balearic lizard Podarcis lilfordi and to assess the relevance of this diversity, and how it is described, to conservation measures. Location: This study covers all the populations of the Balearic lizard, Podarcis lilfordi, present in its range of distribution at coastal islets of Menorca, Mallorca and Cabrera Archipelago. Methods: We analysed genetic and morphological variation across the 43 known extant populations of the Balearic lizard, using mitochondrial and nuclear markers. We examined morphometric and scalation characters using, in some cases, phyloge- netically independent contrasts. We also incorporated the study of dorsal coloration and dorsal colour pattern including the analysis of melanism in several populations. Results: We detected clear genetic divergence between Menorcan populations and populations from Mallorca and Cabrera, in both nuclear and mtDNA markers, but genetic divergence is relatively low among different insular populations within these groups. In contrast, morphological divergence was substantial both between Menorcan and remaining populations and within these groups. Morphological traits, such as dorsal coloration, body size and the number and size of scales, seemed to be linked with differences in climatic conditions between populations. In addition, some traits, as melanism, showed a strong phylogenetic signal. Main conclusions: The morphological and genetic diversity of the Balearic lizard is incongruent with the subspecies described in the classical taxonomic literature. Moreover, current populations differ not only in some genetic and morphological features, but also in several ecological and ethological characteristics, in many cases unique to one population. Based on our results, we propose abandoning the use of subspecies to describe the extraordinary morphological diversity of the Balearic liz- ard and its replacement with the concept of evolutionary significant units (ESUs). ESUs are particularly suitable to describe and recognize such diversity and, especially, to ensure the continuity of the evolutionary process.

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From 1999 to 2005 we studied the population of the dead horse arum, Dracunculus muscivorus (Araceae) and its relationship with the Balearic lizard, Podarcis lilfordi (Lacertidae, Squamata).

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The Balearic lizard, Podarcis lilfordi, is one of the key species of Menorca Biosphere Reserve. This is the only endemic terrestrial vertebrate Plio-Pleistocene, the last representative of vertebrate fauna previous to the arrival of humans. Over the past two decades since the establishment of the Biosphere Reserve, have accumulated a significant amount of knowledge on this species, both on its molecular evolution, as their demographics, characteristics of natural history, ecology, behavior and state conservation of populations Menorcan. However, some fundamental aspects of the situation of current populations are unknown and others provide amazing results from the point of view of Conservation Biology. While some traditional threats affecting the Balearic lizard seem to have disappeared or have been attenuated, new ones have emerged in recent years and old problems, which appeared to be over, have resurfaced. Human pressure on fragile populations of the Balearic lizard is manifested in many different ways and forms, as now, the main factor of uncertainty about the future of this unique species. In this paper, we review summarizes the current state of knowledge on this endemic Lacertidae, try to identify the main factors still act as threats surviving populations in coastal islets and propose some actions that would ensure the future maintenance of P. lilfordi within the Biosphere Reserve.

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We examined the diets of several species of Podarcis from different western Mediterranean islands. We tested the prediction of more generalized diets in lizards from poor environments. We also examined the extert and mode of herbivory in relation to arthropod diversity in the diet. Lizards from the Tuscan Archipelago, P. sicula from Menorca, and P. tiliguerta from Corsica all show a rather generalized diet. In contrast, P. lilfordi and P. pilyusensis from the Balearic Islands and, to a lesser extent, P. hispanica from Benidorm Island, appear much more stenophagous, including a high proportion of clumped prey in their diets. Plant matter is a common food item in most of the population studied, specially in Balearic lizards. A marked seasonal shift in the degree of herbivory was observed in these species where high-energy plant parts are frequently consumed during summer. In one of the Balearic Islands (Nitge), the bulk of the summer diet was formed by pollen and nectar of one particular plant species. Herbivory, consumption of clumped prey and other dietary peculiarities of insular populations of Mediterranean lizards indicate a very flexible feeding behaviour compared to mainland congenerics. This could result from a lack of predation pressure allowing high population densities to be reached in islets with poor trophic resources. Differences found in dietary characteristics among island populations can be interpreted as a consequence of different current ecological conditions, as well as historical and biogeographical differences among the islands.

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Tail autotomy is one of the main anti-predator mechanisms of lacertid lizards, but it has been predicted that it is only retained in its full capacity when its benefits exceed its costs (Arnold, 1988). To test this hypothesis, ease of tail shedding was examined in a number of continental and insular lacertid lizard populations, each of which showed a different shedding capacity. Tails are shed more easily in those continental and insular populations where there is a greater probability of predation. In insular populations not subjected to strong predation, the tail tends to be retained. The relationship of these findings to insular Mediterranean lizard populations and to the extinction of the Balearic lizard, Podarcis lilfordi are discussed.

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Temporal changes in the observed adult sex-ratio might be due to differences in sur- vival or dispersal probabilities. However, in natural populations, it might also be due to an unequal detection probability due to sex-speci c behaviour. To separate these hypotheses, observations should be analysed using an analytical framework that includes the probability of detection, or re- capture, of males and females. We analysed data from an intense capture-mark-recapture study conducted during the spring 2004 at the isle of Aire (Balearic Archipelago) and investigated the demographic mechanisms underlying the observed spring sex-ratio. We used capture-recapture models to simultaneously estimate survival (/f/), proportion of transients (/p) /and the probability of recapture (/p/). We then estimated population size using open population models for individually- based data and compared these with the observed values to validate model estimates. Results indicated that males had a higher probability of recapture than females, but this was not suf cient to generate the observed sex-ratio. The proportion of transient was decreasing during the spring which suggested that sex-dependent movements, most likely linked to the availability of ephem- eral resources, were responsible for the observed difference in the number of males and females. Potential and limitations of the capture-recapture analysis and the in uence of individual hetero- geneity will be discussed.

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Temporal changes in adult sex ratio of animal populations might be due to differences in movements, survival or detection probabilities. We used data from an intensive capture–mark–recapture study of 720 lizards at the islet of Aire (Balearic Islands, Spain) to investigate the demographic mechanisms underlying the spring uneven sex ratio. We simultaneously estimated survival (f), the proportion of transient animals (p) and the probability of recapture (p) of lizards at the study plot. We then estimated population size using open population models for individually based data and compared these with the observed values. Results indicated that males had a higher probability of recapture than females, but this was not sufficient to generate the observed male-biased sex ratio. The proportion of transient males decreased at the end of spring in parallel with the end of the blooming period of the dead horse arum, Helicodiceros muscivorus, a short-lasting food and thermoregulation resource for lizards during spring. Changes in the proportion of transients suggested that sex-dependent movements, most likely linked to a monopolising behaviour of this plant resource, were responsible for the observed difference in the number of males and females. Our results reveal how the interplay of behavioural and ecological factors explains short-term changes in population dynamics and shapes the movement patterns within the island.

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he Balearic lizard, Podarcis lilfordi, is present in 43 insular populations in the Cabrera archipelago and around the coasts of Mallorca and Menorca islands (Spain). We studied lizard densities over the entire range of distribution, analyzing observed differences of density in relation to island area, habitat diversity, availability of resources, presence of predators, competitors and human disturbances. The density of the Balearic lizard varies from less than 35 to almost 8000 lizards ha-1, with an average of around 1500 lizards ha-1. In some very small islets we detected no more than 10 individuals. Using a subsample of nine coastal islets (Menorca) we did not find any significant correlation between ground arthropod biomass and lizard density. The combination of island area and its maximal altitude, its so-called biotic capacity, was also uncorrelated with lizard density. In addition, neither degree of island accessibility nor presence/absence of seagull breeding colonies, were able to explain lizard densities. Islands without ship rats (Rattus rattus) showed a significantly higher lizard density, but islands in which rat eradication programs were launched during the study period, showed lower densities than those with rats but no eradication actions. Genetic variability was significantly higher on bigger lizard populations, lacking a correlation with lizard densities. No single independent variable can explain density differences among populations under study. Our results are discussed in the light of available hypotheses on factors affecting population densities.

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An analysis of pollen grains loaded and transported by the Balearic lizard, Podarcis lilfordi, at three coastal islets of Menorca (Balearic Islands, Spain) was performed. We studied 228 individual lizards from spring and summer, 1998, recording 323,986 pollen grains belonging to 35 different plant species. As a consequence of its foraging behavior, the Balearic lizard is able to load large quantities of pollen. In Aire Island pollen load was higher in adult females than males. P. lilfordi is an important pollen loader of some plant species such as Pistacia lentiscus, Crithmum maritimum, Allium ampeloprasum, Carlina corymbosa, and Pancratium maritimum. The role of P. lilfordi as the main pollinator has been previously demonstrated only for the sea fern, C. maritimum. However, results reported here indicate that the Balearic lizard can play an important role in the reproductive success of other plant species on coastal islets off the main island of Menorca.

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Coastal islets of Balearic Islands share several ecological conditions, such as the scarcity of food resources and the lack of a strong predation pressure. During spring and summer 2006, we studied the thermal ecology of two populations of the Balearic lizard, Podarcis lilfordi, from two different coastal islets of Menorca (Balearic Islands, Spain): Aire and Colom. In both islets and seasons, we found that P. lilfordi regulates its body temperature rather accurately, showing effectiveness values ranging between 0,8 and 1. During spring at Aire islet, the vast majority of operative temperatures (Te) were out of the optimum range (Tsel). But, nevertheless, the Balearic lizard performed an effective thermoregulation. Lizards remained active in both islets for as long as they were able to, and were only inactive in the late afternoon of summer days. We found significant differences in Te from different habitats, showing a high heterogeneity of the thermal conditions in both islets under study. This habitat heterogeneity allows an effective shuttling heliothermic behavior of lizards. Differences found between islets are notable. There is a dramatic increase of thermoregulation accuracy between seasons in Aire, markedly less pronounced in Colom. Based on our study, we foreview that wind would produce a cooling effect, that would be stronger in Aire than Colom. Hence, in Aire islet, there was a more effective thermoregulation in summer than spring. Further research needs doing in order to check the potential role of melanism and other factors in such thermoregulation differences amongst populations of the same species.

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While the use of faecal pellets is widely accepted as a primary methodological source of data for dietary studies, a recent paper advocated for the use of gut contents. This was due to the fact that faecal samples would give biased results of the diet of arthropod predators, due to a lower representation of soft-bodied prey in faecal pellets. To test this assumption, we compared the spring diet of several populations of two insular lizards from the Balearic Islands (Spain), Podarcis lilfordi and Podarcis pityusensis, using both faecal pellets and gut contents. Our results do not support the supposed bias of dietary analyses based on faecal pellets. Indeed, soft-bodied prey and particularly insect larvae are often equally represented in faecal pellets and gut contents. Alternatively, soft bodied prey are represented in different proportions in gut contents and faecal pellets, but in some cases with higher proportions being observed in the gut contents, and in other cases with higher proportions in faecal samples. We conclude that faecal pellets can be a reliable source of information for dietary studies.

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The ecological conditions of Mediterranean islands favour the consumption of vascular plants by lizards and, consequently, the raise of several interactions, including plant pollination and seed dispersal. However, some interactions can be more complicated, with variable benefits or detrimental effects for lizards and plants. In this talk we describe the striking case of the Dead Horse Arum and the Balearic Lizard in Aire (Illa de l`Aire), a coastal islet of Menorca.

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In this work we describe the interaction of the dead horse arum and the Balearic lizard in Aire (Balearic Islands, Spain). In Aire Island (Illa de l`Aire), the dead horse arum, Dracunculus muscivorus, is particularly abundant. From 1999 to 2005 we studied the population of this plant species and its relationship with the Balearic lizard, Podarcis lilfordi. During blooming period, several lizards exhibited an intense foraging behaviour focused on open inflorescences. Lizards were able to capture flies attracted by the plants and those trapped in tubules as pollinators. The exploitation of pollinators was principally made by largest males of the population that actively excluded females and smaller males from plants, skewing lizard sex-ratio in areas of maximum plant density. Lizards consumed fruits following the progressive fruit maturation. In two germination experiments, we detected an enhanced germination of seeds from lizards’ faeces, in comparison with those directly taken from ripening fruits. Thus, the Balearic lizard is the main legitimate disperser of the dead horse arum. From 1999 to 2005, the density of the dead horse arum increased from 4800 ind./ha to more than 25.000 ind./ha in some optimal areas of the islet, indicating a very positive balance of the interaction between plants and lizards.

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A studie was carried out on 17 populations of Podarcis lilfordi inhabiting the islets off the coast of Menorca (Balearic Islands). Pattern and colouring together with the statistical analysis performed suggested that the menorcan rassenkreis comprises a total of 9 subspecies. The evolutionary processes involved appear to be fundamentally governed by the age of the islets, their distance from the coast and by their ecological conditions. Though in certain cases it may be postulated that genetic drift may have acted as a differentiating mechanism in populations which were initially small. However, interpretation of the microevolutionary processin Menorca is more difficult thnin the case of other rassenkreis of the Balearic Islands due to extinction of the `mother` population on the main island.

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A 684 bp fragment from cytochrome-b allowed a coherent arrangement of several Podarcis populations from the Balearic archipelago, in a study focused on the phylogeography of the 15 Minorcan populations of Podarcis lilfordi. A reference site with Podarcis lilfordi from Mallorca clusters with the Minorcan population, although it shares a few variations with Podarcis pityusensis that are not present in the Minorcan clade. Concerning the Minorcan islets, a two steps model is drawn accounting for the observed molecular pattern. An ancient and a derived stock of populations can be discerned, seperated by a population event replacing the former populations by the modernones on the shallowest protoislets, placing it around 7000 to 5000 BP, based on bathymetric information and Holocene sea level data. Autapomorphies are present in several sites and could be indicative of seperated demes prevailing on penninsular areas of the island, as in Cavalleria, Mola de Fornells, or even on larger regions as in the southeast Menorca. Within the framework of a vicariant model, we suggest that islet`s inhabitantshave thus retained some of the history of the now extinct mainland population.

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The Balearic lizard P. lilfordi inhabits the Gymnesies Islands and have sexual dimorphism. By means of biometric studies and analyses such as the discriminant analysis, it has been determined the morphometric characters that determine this sexual dimorphism. The characters chosen by the analysis were: body length, pileus width, number of gular scales, length of the four finger of the posterior leg. The differential measures of these characters makes the males to have a burlness and robustness greater than the females of the same population. Nevertheless, it cannot be said that in all P. lilfordi populations, the males will be aways the most burliness and robustness,but this will depend upon th population of P. lilfordi we take into consideration.

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Comparisons among eight populations of Podarcis lilfordi, seven of Podarcis pityusensis (representative lizards of the Balearic Archipielago), and one of Podarcis hispanica atrata fro the Columbretes Islands, have been made from a morphological point of view, measuring 15 morphometric characters of the lizards. Cluster and discriminant analyses were obtained for males and females to show the relationships among the different populations and species. These analyses gave three groups: one of them with the most P. lilfordi populations, other with the most P. pityusensis populations, and a well seperated group with the P. hispanica atrata species. Some populations connect the groups of P. lilfordi and P. pityusensis. The possibility that P. lilfordi and P. pityusensis be two pattern of variation inside the same species instead of two well differentiated species is considered, altrough further studies are necessary.

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The effect of several abiotic and biotic factors (island area, distance from a potential colonizing source, sex, age and diet of the host) on helminth diversity of the endemic balearic lizards Podarcis pityusensis and Podarcis lilfordi caught on small islets of the Balearic islands, has been studied.

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The knowledge of the helminth communities of reptiles and their ecological relationships with their hosts are until the present not well known. Some general researches have been made only on American herps (AHO 1990). Recently, ROCA & HORNERO (1991a, 1991b) attempted similar kind of researches from Mediter- ranean insularlizards.

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A number of the subspecies were studied over several visits to Formentera and Ibiza. Podarcis pityusensis pityusensis is found on Ibiza. However, several animals of different colours were found not all of which conformed to the for that island described subspecies. Furthermore, on Formentera different forms of Podarcis pityusensis formenterae were observed. Three hybrids resulting from a cross between a male Podarcis lilfordi giglioli (Sa Dragonera) and a female Podarcis pityusensis formenterae were born under terrarium conditions. These hybrids proved to be fertile, after mating with Podarcis lilfordi lilfordi (Illa de l`Aire) males these three females laid 12 eggs. Due to a number of circumstances only one egg hatched but a normal young was produced. The various forms of Podarcis pityusensis are found not only on small islets but also on the main islands. Their presence seems to be dependent on the substrate. The hybrids and the various forms of Podarcis pityusensis on the main islands makes it questionable whether the classification of these animals into a great number of subspecies, or even into two species, is justified.

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Aim To describe and analyse phylogeographical patterns in the endangered endemic lizard Podarcis lilfordi from across its remaining range and thereby establish baseline information on genetic diversity that will help determine conservation priorities and assist future reintroduction programs. Location Balearic Islands, Spain. Methods We analysed mitochondrial DNA (2382 bp sequence from eight genes) from 118 individuals and characterized the relationships among haplotypes using parsimony networks, as well as phylogenetic inference. Analyses of historical gene flow and population growth were used to provide further insights into population histories. Results Four unconnected parsimony networks were obtained that mirrored the main clades in the phylogenetic tree: (I) all Menorcan populations, (II) Dragonera, Malgrats and Toro islands (Western Mallorca) (III and IV) and the remaining populations from Cabrera and Mallorca. Two major haplotype groups were detected in Menorca (I) and these provided signatures of a demographic expansion and asymmetrical historical gene flow, respectively, concordant with the expected direction of colonization from south to north of the island. Populations from western Mallorca (II) showed evidence of historical allopatric fragmentation events following isolation around the start of the Pleistocene. In networks III and IV, Cabreran populations appear to have become isolated from north and south Mallorca quite recently, with asymmetric gene flow indicating a northwards dispersal direction. Main conclusions P. lilfordi is a genetically diverse species that shows substantial mtDNA structuring both between regions and, at a finer scale, between some islet populations within regions. The precarious state of some islet populations shown here to be quite divergent (e.g. Toro island in western Mallorca) means that conservation of this intraspecific biodiversity requires urgent action.

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Presentation held at the annual meeting of the AG Lacertiden in Gersfeld/Rhön the 10th of April 2011. It is reported about the rediscovery of a population of the Balearic Lizard (Podarcis lilfordi) on the Illa de Ses Mones in the harbour of Port d´Addaia. This population has been considered to have become extinct during the 1990s due to the introduction of the Italian Wall Lizard (Podarcis siculus). Descriptions of the island and the lizards are given and for the first time it is reported about the sympatric occurrence of Podarcis lilfordi and Podarcis siculus. Because in quite a lot of publications the nearby Illot d´en Carbó has been confused with the Illa de Ses Mones the taxonomic status of the rediscovered Podarcis lilfordi population from the Illa de Ses Mones and the Podarcis lilfordi carbonerae population of Illot d`en Carbó are discussed.