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1. The signals that animals use to communicate often differ considerably among species. Part of this variation in signal design may derive from differential natural selection on signal efficacy: the ability of the signal to travel efficiently through the environment and attract the receiver`s attention. For the visual and acoustic modalities, the effect of the physical environment on signal efficacy is a well-studied selective force. Still, very little is known on its impact on chemical signals. 2. Here, we took a broad, phylogenetic comparative approach to test for a relationship between animals` signal chemistry and properties of their natural environment. Our study focused on lizards from the Lacertidae family. 3. We sampled 64 species across three continents and determined the lipophilic composition of their glandular signalling secretions using gas chromatography-mass spectrometry. For each species, an array of environmental variables of high temporal and spatial resolution was obtained from climate databases. 4. Species varied considerably in the overall richness (number of constituents) of their secretions, as well as in the relative contribution of the major chemical compound classes. Signal richness and the relative contribution of the respective compounds exhibited little evidence of phylogenetic relatedness, suggesting that chemical signals may change very rapidly. Neither insularity nor substrate use affected chemical signal composition, however, we found a strong statistical relationship between the chemistry of the lizards` secretions and aspects of the thermal and hydric environment they inhabit. 5. Species from `xeric` milieus contained high proportions of stable fatty acid esters and high molecular weight alcohols in their glandular secretions, which likely increase the persistence of secretion scent-marks. In contrast, species inhabiting `mesic` environments produced secretions of a high chemical richness comprising high levels of aldehydes and low molecular weight alcohols. This chemical mix probably creates a volatile-rich signal that can be used for long-distance airborne communication. 6. We argue that the observed variation in signal design results from differential natural selection, optimizing signal efficacy under contrasting environmental conditions.

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The phylogenetic affinities of Acanthodactylus beershebensis, a highly endangered lacertid lizard endemic to the Neguev (Israel), were assessed using mtDNA markers. Fragments of 12S and 16S rRNA were analysed and compared with already published sequences of Acanthodactylus. Results corroborate the taxonomic placement of A. beershebensis as a member of the A. pardalis group but place it within a polytomy at the same phylogenetic level as other (unnamed) African populations. This pattern of high but poorly structured genetic diversity, previously observed for other Acanthodactylus complexes, has been suggested to derive from the climatic instability of North Africa and the Middle East during the humid and dry periods of the Pleistocene as well as dune migrations. In conservation terms, if A. beershebensis is to be prioritised, then other populations of the A. pardalis group inhabiting North Africa would deserve a similar status, making their species definition urgent. These results highlight the need for considering phylogeny when establishing conservation priorities.

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Colorful tails that become cryptic during ontogeny are found in diverse taxa. Nevertheless, the evolutionary bases for this change remain debated. Recent work suggests that colorful tails, deflective displays, and striped patterns may represent antipredator mechanisms used by immature lizards to compensate for being more active and hence more vulnerable to predation (increased movement hypothesis, IMH). I challenged the generality of IMH by comparing foraging behavior and frequency of tail displays across five Acanthodactylus lizards that vary in fundamental life history traits, before and after the tail changed color. As these species underwent changes in tail coloration, they congruently adopted less risky behaviors and reduced the frequencies of tail displays. Contrary to expectation, in two species, the hatchling risky behavior resulted not from increased movements but from longer stay in exposed microhabitats. I suggest that colorful tails and deflective tail displays are synergistic antipredator mechanisms neonates use to minimize the fitness consequences of using various risky behaviors rather than increased movement alone.

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Theory predicts that predators can reduce parasite abundance on prey by reducing prey density and through disproportionate predation on heavily infested individuals. We experimentally tested this prediction by examining the effects of bird predation on parasitic mite infestation of the prey lizard Acanthodactylus beershebensis. We manipulated predation by adding perches to arid scrubland, allowing avian predators to hunt for lizards in a habitat the birds would not normally use. Host density influenced parasite abundance in hatchlings, but not in older aged individuals and parasite abundance did not affect lizard host survival. Contrary to expectation mite abundance on adult lizards increased under low predation intensities. We explain these results by suggesting a novel hypothesis based on the assumption that the two components of predation, i.e. actual removal of prey and risk, exert contradictory effects on macroparasite abundance.

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Ontogenetic changes in color and pattern that are not directly related to reproduction are very common yet remain a poorly understood phenomenon. One example is conspicuous colors in the tails of fish, amphibians, and reptiles that fade out later in life. We suggest a novel hypothesis: conspicuous tail colors that appear only in juveniles compensate for an increased activity level, deflecting imminent attacks to the tail. We observed blue-tailed, newly hatched lizards (Acanthodactylus beershebensis) in the field and compared 5 behavioral parameters with those of older individuals that had already lost their neonate coloration. In addition, we explored whether tail displays, often assumed to direct a predator`s attention to the tail, disappear with the color change. Striped blue-tailed hatchlings foraged more actively than 3-week-old juveniles, spent a longer time in open microhabitats, and performed deflective tail displays. In comparison, 2 other lacertids that do not undergo ontogenetic change did not switch to safer foraging when growing up. The results suggest that activity alteration may be a major factor affecting the ontogenetic color and pattern change. Active lizards that forage in open habitats increase their probability of attack by ambush predators. Conspicuous colors and deflection displays may shift attacks to the expendable tail, increasing the prey`s overall probability of surviving attacks. The persistence of both striped body pattern and blue tail fits the active foraging period of neonates and hence may be appropriate for other species that display a conspicuous tail accompanied by a striped pattern.

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1 Patch structural complexity affects local species richness and population densities. Anthropogenic disturbance may alter complexity and heterogeneity, resulting in changes in community structure. Most studies in this area have dealt with human-induced habitat degradation. We investigated a converse situation, in which anthropogenic activity increases productivity and complexity of an arid habitat. 2 Recently, large areas in the northern Negev Desert have been altered: a series of contour catchments was constructed to accumulate run-off to support planted trees. We examined the effect of patch alteration by focusing on the lizard assemblage in the planted plots. Seven pairs of plots were established, one plot from each pair in a natural area and the other in an adjacent, altered slope. Lizards were captured using pitfall traps and environmental parameters were measured. To isolate the effects of trees as perches for avian predators, we ‘planted’ artificial trees in a loess plain and investigated the effect on an endemic lizard. 3 The structure of the lizard assemblage in the planted plots differed from that of the natural plots. Planted plots had a higher proportion of Mediterranean lizards and fewer desert species. Two local lizard species disappeared from the mosaic area of planted and natural plots. In addition, avian predators spent longer time in the artificial tree plots and reduced the lizard density compared to the natural plots. 4 The modification to the habitat generated only moderate changes in structure of the natural vegetation and this could not account for the observed changes in the lizard assemblage. Changes in the spatial use of the plots by avian predators was identified as the mechanism behind the observed distribution of lizard species. 5 Synthesis and applications. We argue that anthropogenic habitat modifications such as afforestation, urbanization, etc., can induce indirect biotic effects that may change the way and the scale at which different species respond to the habitat change. Such structural alteration may lead to species replacement and even to local extinction of specialist species. In order to protect biodiversity during large-scale management projects, alteration of biotic interactions should be considered in advance and large unaltered patches should be protected, otherwise indirect effects might cause greater impacts than the structural manipulation itself.

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Animal feeding ecology and diet are inXuenced by the fear of predation. While the mechanistic bases for such changes are well understood, technical diYculties often prevent testing how these mechanisms interact to aVect a mesopredator’s diet in natural environments. Here, we compared the insectivorous lizard Acanthodactylus beershebensis’ feeding ecology and diet between high- and low-risk environments, using focal observations, intensive trapping eVort and fecal pellet analysis. To create spatial variation in predation risk, we planted “artiWcial trees” in a scrubland habitat that lacks natural perches, allowing avian predators to hunt for lizards in patches that were previously unavailable to them. Lizards in elevated-risk environments became less mobile but did not change their microhabitat use or temporal activity. These lizards changed their diet, consuming smaller prey and less plant material. We suggest that diet shifts were mainly because lizards from risky environments consumed prey items that required shorter handling time.

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Anthropogenic habitat perturbation is a major cause of population decline. A standard practice managers use to protect populations is to leave portions of natural habitat intact. We describe a case study in which, despite the use of this practice, the critically endangered lizard Acanthodactylus beershebensis was locally extirpated from both manipulated and natural patches within a mosaic landscape of an afforestation project. We hypothesized that increased structural complexity in planted patches favors avian predator activity and makes these patches less suitable for lizards due to a heightened risk of predation. Spatial rarity of natural perches (e.g., trees) in arid scrublands may hinder the ability of desert lizards to associate perches with low-quality habitat, turning planted patches into ecological traps for such species. We erected artificial trees in a structurally simple arid habitat (similar to the way trees were planted in the afforestation project) and compared lizard population dynamics in plots with these structures and without. Survival of lizards in the plots with artificial trees was lower than survival in plots without artificial trees. Hatchlings dispersed into plots with artificial trees in a manner that indicated they perceived the quality of these plots as similar to the surrounding, unmanipulated landscape. Our results showed that local anthropogenic changes in habitat structure that seem relatively harmless may have a considerable negative effect beyond the immediate area of the perturbation because the disturbed habitat may become an ecological trap.

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Anthropogenic changes, such as land use, are the main drivers causing climate change and biodiversity loss, with hundreds of thousands of species lacking sufficient habitats for their populations to persist and likely to go extinct within decades. Endemic species are more susceptible to habitat changes and are at the forefront of the biodiversity crisis. We used species distribution models to generate a relative habitat suitability map and identified the habitat requirements of the critically endangered and endemic Be`er Sheva fringe-fingered lizard {Acanthodactylus beershebensis). The model showed that the species` suitable habitats are associated with arid loess plains characterized by scattered, low vegetation cover, primarily on north-facing aspects, suggesting that these species-specific habitat requirements limit its distribution. The size of the potentially suitable area within the species` historical range is 1350.73 km2. However, anthropogenic changes decreased the remaining suitable habitat to 995.04 km2. Most of this area is unprotected and at risk of further adverse anthropogenic effects. Only 91.72 km2 of this area is protected by the Israel Nature and Parks Authority, and 587.11 km2 may be considered indirectly protected because it is within military firing zones. Our study is the first attempt to map the remaining suitable habitat of A. beershebensis based on the results of a species distribution model. The results of this model can assist in prioritizing the protection of areas needed for the conservation of this critically endangered and endemic lizard species.

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Aim Temperature influences most components of animal ecology and life history – but what kind of temperature? Physiologists usually examine the influence of body temperatures, while biogeographers and macroecologists tend to focus on environmental temperatures. We aim to examine the relationship between these two measures, to determine the factors that affect lizard body temperatures and to test the effect of both temperature measures on lizard life history. Location World-wide. Methods We used a large (861 species) global dataset of lizard body temperatures, and the mean annual temperatures across their geographic ranges to examine the relationships between body and mean annual temperatures.We then examined factors influencing body temperatures, and tested for the influence of both on ecological and life-history traits while accounting for the influence of shared ancestry. Results Body temperatures and mean annual temperatures are uncorrelated. However, accounting for activity time (nocturnal species have low body temperatures), use of space (fossorial and semi-aquatic species are ‘colder’), insularity (mainland species are ‘hotter’) and phylogeny, the two temperatures are positively correlated. High body temperatures are only associated with larger hatchlings and increased rates of biomass production. Annual temperatures are positively correlated with clutch frequency and annual longevity, and negatively correlated with clutch size, age at first reproduction and longevity. Main conclusions Lizards with low body temperatures do not seem to have ‘slower’ life-history attributes than species with high body temperatures. The longer seasons prevalent in warm regions, and physiological processes that operate while lizards are inactive (but warm enough), make environmental temperatures better predictors of lizard life-history variation than body temperatures. This surprisingly greater effect of environmental temperatures on lizard life histories hints that global warming may have a profound influence on lizard ecology and evolution.

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Examination of 385 specimens of the Acanthodactylus pardalis group from eastern Libya, Egypt and Israel confirmed the occurrence of two allopatric species in this area: Acan-thodactylus pardalis (Lichtenstein, 1823) distributed in Egypt and eastern Libya and a hitherto undescribed species endemic to the Negev (Israel). The species differ most markedly in body size, hemipenial structure, colouration and details of sexual dichromatism. Other significant dif-ferences involve scalation and biometrics. A simple method for artefact-free use of discriminant analysis in multivariate classification is presented. Redescription of A. pardalis (Lichtenstein, 1823), description of a new species Acanthodactylus beershebensis sp.n. and corrected geo-graphical ranges of the two species are provided. Both species, each endemic to a small area, appear to be markedly endangered by habitat destruction.

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Many animals display complex colour patterns that comprise several adjacent, often contrasting colour patches. Combining patches of complementary colours increases the overall conspicuousness of the complex pattern, enhancing signal detection. Therefore, selection for conspicuousness may act not only on the design of single colour patches, but also on their combination. Contrasting long- and short-wavelength colour patches are located on the ventral and lateral surfaces of many lacertid lizards. As the combination of long- and short-wavelength-based colours generates local chromatic contrast, we hypothesized that selection may favour the co-occurrence of lateral and ventral contrasting patches, resulting in complex colour patterns that maximize the overall conspicuousness of the signal. To test this hypothesis we performed a comparative phylogenetic study using a categorical colour classification based on spectral data and descriptive information on lacertid coloration collected from the literature. Our results demonstrate that conspicuous ventral (long wavelength-based) and lateral (short wavelength-based) colour patches co-occur throughout the lacertid phylogeny more often than expected by chance, especially in the subfamily Lacertini. These results suggest that selection promotes the evolution of the complex pattern rather than the acquisition of a single conspicuous colour patch, possibly due to the increased conspicuousness caused by the combination of colours with contrasting spectral properties.

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Acanthodactylus lizards are among the most diverse and widespread diurnal reptiles in the arid regions spanning from North Africa across to western India. Acanthodactylus constitutes the most species-rich genus in the family Lacertidae, with over 40 recognized species inhabiting a wide variety of dry habitats. The genus has seldom undergone taxonomic revisions, and although there are a number of described species and species-groups, their boundaries as well as their interspecific relationships are largely unresolved. We constructed a multilocus phylogeny, combining data from two mitochondrial (12S, cytb) and three nuclear (MC1R, ACM4, c-mos) markers for 302 individuals belonging to 36 known species, providing the first large-scale time-calibrated molecular phylogeny of the genus. We evaluated phylogenetic relationships between and within species-groups, and assessed Acanthodactylus biogeography across its known range. Acanthodactylus cladogenesis is estimated to have originated in Africa due to vicariance and dispersal events from the Oligocene onwards. Radiation started with the separation into three clades: the Western and scutellatus clades largely distributed in North Africa, and the Eastern clade occurring mostly from Arabia to south-west Asia. Most Acanthodactylus species diverged during the Miocene, possibly as a result of regional geological instability and climatic changes. We support most of the current taxonomic classifications and phylogenetic relationships, and provide genetic validity for most species. We reveal a new distinct blanfordii species-group, suggest new phylogenetic positions (A. hardyi, A. masirae), and synonymize several species and subspecies (A. lineomaculatus, A. boskianus khattensis and A. b. nigeriensis) with their phylogenetically closely-related species. We recommend a thorough systematic revision of taxa exhibiting high levels of intraspecific variability as well as clear evidence of phylogenetic complexity such as A. guineensis, A. grandis, A. dumerilii, and A. senegalensis and the pardalis and erythrurus species-groups.

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A new species of the Acanthodactylus pardalis group, A. ahmaddisii sp.n., is described from Jordan, from a single specimen which differs from A. pardalis (Lichtenstein, 1823) of east- ern Libya and Egypt, and A. beershebensis Moravec et al., 1999 from Israel. Compared to the lat- ter two populations, A. ahmaddisii is larger with smaller head and shorter appendages and fewer (larger) dorsals. It also differs in qualitative pholidotic characters, especially by having tricarinate subdigitals, and in colour pattern.

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The distribution of the Arabian desert lizard Acanthodactylus opheodurus Arnold, 1980 in the Levant is re-examined. West of Jordan it is almost limited to the ‘Arava Valley, absent from most of the Negev and from Sinai. This correction of an earlier report derives from re-identification of specimens, relying on the colour pattern difference from the syntopic sibling A. boskianus asper (Audouin, 1829). The vertebral dark stripe is simple in A. opheodurus but forked in A. boskianus. The vertebral stripe is forked but light-colored in two geographically adjacent related taxa, A. b. boskianus (Daudin, 1802) of northern Egypt and A. schreiberi syriacus Boettger, 1878 of coastal Israel.