Daniele Pellitteri-Rosa

Photographic identification in reptiles: a matter of scales

Photographic identification is a promising marking technique alternative to the toe-clipping, since it is completely harmless, cheap, and it allows long time identification of individuals. Its application to ecological studies is mainly limited by the time consuming to compare pictures within large datasets and the huge variation of ornamentation patterns among different species, which prevent the possibility that a single algorithm can effectively work for more than few species. Scales of Reptiles offer an effective alternative to ornamentations for computer aided identification procedures, since both shape and size of scales are unique to each individual, thus acting as a fingerprint like ornamentation patterns do. We used the Interactive Individual Identification System (I 3 S) software to assess whether different individuals of two species of European lizards ( Podarcis muralis and Lacerta bilineata ) can be reliably photographically identified using the pattern of the intersections among pectoral scales as fingerprints. We found that I 3 S was able to identify different individuals among two samples of 21 individuals for each species independently from the error associated to the ability of the operators in collecting pictures and in digitizing the pattern of intersections among pectoral scales. In a database of 1043 images of P. muralis collected between 2007 and 2008, the software recognized 98% of recaptures within each year, and 99% of the recaptures between years. In addition, 99% and 96% of matches were ranked among the top five, and no more than 5 minutes were needed for digitizing and processing each image. The lepidosis of reptiles is a reliable alternative to ornamentation patterns in photographic identification of reptiles, which can be effectively analysed using the I 3 S software. This result represents a significant improvement in photographic identification of reptiles since (i) this procedure can be easily extended to most other species of reptiles, (ii) all kind of individuals within a species can be marked (i.e., young, subadults and adults) despite the differences in ornamentation patterns, and (iii) it is the only technique for species, like the western green lizard, which lack a clear ornamentation pattern.

Sex-, morph- and size-specific susceptibility to stress measured by haematological variables in captive common wall lizard Podarcis muralis.

In polymorphic species of animals, colour morphs may show alternative physiological properties, and hence evolve or be maintained as an indirect response to selection exerted on these physiological attributes. In this study, we investigated if different colour morphs (white, red and yellow) of the polymorphic common wall lizard differed in their physiological responses to a long-term stress by determining variation between capture and release in leukocytes profiles, haemoparasite loads and body condition of male and females maintained in captivity throughout the breeding season. We found that most blood parameters of lizards varied significantly following captivity, and this variation was sex-, morph- and size-dependent. In particular, the heterophil:lymphocyte ratio (H:L), a sensitive measure of immunodepression and long-term stress, varied significantly among yellow females, larger individuals significantly increasing and smaller individuals decreasing their H:L ratio after captivity. This trend was reversed in red females, where smaller individuals presented raised H:L index at release. Our study indicated that response to long-term stressful conditions, such as those induced by captivity, differed among common wall lizard colour morphs, implying a sex-, size-(i.e. age) and morph-specific sensitivity to stress, and hence a different physiological profile of colour morphs, which may contribute to the maintenance of colour polymorphism in this species.

Colour Polymorphism and Alternative Breeding Strategies: Effects of Parent’s Colour Morph on Fitness Traits in the Common Wall Lizard

Colour polymorphism (CP) is widespread in animals, but mechanisms underlying morph evolution and maintenance are not completely resolved. In reptiles, CP is often genetically based and associated with alternative behavioural strategies, mainly in males for most cases. However, female colour morphs also display alternative reproductive strategies associated with behavioural and physiological traits, which may contribute to maintain CP in the population. Both sexes of the common wall lizard (Podarcis muralis) show three pure colour morphs, white, yellow and red. Here, we looked for the effects of male and female colour morphs on fitness traits of captive-breeding pairs. All yellow-throated females laid clutches of many small eggs and produced many light offspring, behaving as r-strategists, whereas white-throated females laid clutches of few large eggs and produced few heavy offspring, behaving as K-strategists. Red-throated females adopted a conditional Kr-strategy depending on their size/age. These basic female strategies were modulated in relation to mate morph: white females had the best fitness gain in terms of viable offspring when mated to red males; mating between yellow morphs yielded a greater breeding success than all other morph crosses, but also lighter offspring; finally, red females produced heavy progeny when paired with red or white males, and light offspring in pair with yellow males. Thus, correlation between CP and traits relevant to fitness combined with non-random mating, either assortative or disassortative, could increase the potential for CP to contribute to divergent evolution in the common wall lizard.

Leukocyte differential counts and morphology from twelve European lizards

Abstract The present study reports the morphology of leukocytes of 12 European lacertid lizards (Podarcis sicula, P. tiliguerta, P. melisellensis, P. bocagei, P. muralis, Algyroides nigropunctatus, Lacerta viridis, L. bilineata, L. trilineata, L. oxycephala, Timon lepidus, and Zootoca vivipara) stained using May–Grünwald/Giemsa method. The morphology of white blood cells was very similar among species, suggesting a relative morphological uniformity within the lacertid lizards. For six species (i.e. P. sicula, P. tiliguerta, P. melisellensis, P. bocagei, P. muralis, and A. nigropunctatus), we determined the leukocyte differential counts, which may be considered representative of the normal values of the corresponding populations. These results may be useful either in clinical investigation to detect pathologies in wild individuals, as in management and conservation projects to assess the general health conditions of natural wild lizard populations.

The yellow cheek-patches of the Hermann's tortoise (Reptilia, Chelonia): Sexual dimorphism and relationship with body condition

Abstract Males and females of Hermanns tortoise (Testudo hermanni) exhibit a conspicuous yellow patch on both their cheeks, whose origin and potential function are totally unknown. In this study, we measured the extent and the colour intensity of these patches in 29 male and 19 female tortoises in order to test for sexual difference in these features. In addition, we analysed the relationships between patch features and body condition to investigate the possible function of these ornaments as status signals. We detected symmetric yellow patches in all sampled females, while five males did not show at all the ornament, and two had a yellow patch only on the left cheek. Although head and scale size, as well as RGB values, did not differ between sexes, female patches were significantly larger than those of males. In addition, the extent of cheek patches was correlated to female body condition, suggesting that these ornaments may have evolved as honest signals of quality through sexual selection processes driven by female–female contests over rank or by male mate choice.

Courtship Displays Are Condition-Dependent Signals That Reliably Reflect Male Quality in Greek Tortoises, Testudo graeca

Abstract The courtship behavior of male Greek tortoises (Testudo graeca) is based on a multiple signaling system that involves tactile, visual, olfactory, and acoustic signals. In some recent studies on marginated (Testudo marginata) and Hermanns tortoises (Testudo hermanni) we showed that male mounting success was significantly and positively correlated to the intensity of courtship displays. This was due to the number of rams and bites and the number of calls emitted during mounting, which are considered to be condition-dependent signals that reliably convey information on male quality. In this correlative study, we analyzed relationships between male morphology, hematological profile, courtship intensity, vocalizations, and mounting success in a group of 104 Greek tortoises breeding in seminatural enclosures. As expected, our study showed that mounting success of males was positively correlated to the number of rams and the frequency of interactions during courtship and negatively correlated to the call duration. Moreover the hematocrit was positively correlated with the call rate and the number of rams. Therefore, courtship signals exhibited by male Greek tortoises, including vocalizations, reliably reveal different components of male condition, and females may use these signals to choose high-quality partners, as previously observed in marginated and Hermanns tortoises.

Urbanization affects refuge use and habituation to predators in a polymorphic lizard

Prey–predator interactions are plastic behaviours shown by both players, which constantly modify their decisions depending on physiological conditions and ecological context. We investigated whether the behavioural response to repeated simulated predatory attacks varied between adult males of the common wall lizard, Podarcis muralis, inhabiting environments characterized by different degrees of human presence. Our aim was to detect possible effects of urbanization on antipredator responses, in terms of activity, time spent hidden in refuges and habituation. Moreover, since this lizard species exhibits intrapopulation colour polymorphism, we looked for the occurrence of possible correlations between antipredator strategy and individual ventral coloration. We found that urban lizards spent less time in their refuge after predatory attacks and decreased successive hiding times faster than rural lizards, suggesting different wariness towards a potential predator. Irrespective of population, yellow lizards gradually spent less time in the refuge before appearing and emerging outside than the other two morphs. Conversely, red lizards showed progressively longer appearance and emergence times after successive tests, suggesting a growing sensitization to the potential threat of a predatory attack. In conclusion, our study showed the occurrence of different levels of behavioural plasticity in common wall lizards antipredator response: the population level, depending on ecological context, here different degrees of exposure to human disturbance, and the individual level, which suggests the occurrence of morph-specific antipredator strategies. Thus, using a lizard species as a model, we shed light on two key points of evolutionary ecology concerning both the antipredator response and the factors driving the maintenance of intraspecific polymorphism.

A Comparison among Sexual Signals in Courtship of European Tortoises

Abstract Complex and ritualized displays require an assemblage of structural, neuronal, and muscular adaptations, and habitat structure may affect the effectiveness of signals to convey information. Therefore, ornament exaggeration through sexual selection may be severely constrained by the costs imposed by natural selection. We investigated this compromise in the courtship behavior of Mediterranean Tortoises by assessing the variability of the acoustic and behavioral signals used among species, and the relationship between courtship and species body size. Marginated, Greek, and Hermanns Tortoises base their courtship on the same kinds of displays, and differences among species rely mainly on the relative importance of aggressive displays with respect to acoustic signals. We found that the divergence of courtship patterns among species was also related to body size. Greek Tortoises, intermediate in size between the other two species, showed an intermediate courtship aggression. Body size in Mediterranean Tortoises relates to different vegetation structure of their preferred habitat, smaller species being advantaged in denser vegetation. Therefore, the divergence of courtship patterns in the three species of European tortoises might have been promoted by the progressive adaptation of incipient species to habitats with different vegetation structures. Because courtship signals play a central role in species isolation, a link between morphology and courtship is of particular interest and might be one of the central mechanisms of tortoise diversification.

Do Hermann's tortoises (Testudo hermanni) discriminate colours? An experiment with natural and artificial stimuli

Abstract Many animals use chemical and visual cues to obtain reliable information about potential food resources. Most reptiles have evolved highly specialized chemosensory and visual capacities, in particular colour vision, to accomplish this task. By presenting animals with flowers and coloured cardboard discs in two-choice experiments, we examined whether both male and female Hermanns tortoises (Testudo hermanni) were able to distinguish between different colours, and show some preference for certain colours. We found that both sexes responded and discriminated equally between different colours, with some differences between flowers and discs. In particular, the red was preferred in the disc experiment, mainly by males, but was disregarded by both sexes in the flower experiment, where red was represented by poppy, Papaver rhoeas. This suggests that Hermanns tortoise probably relies on a mixed system of olfactory and visual abilities to detect food in order to optimize the intake of essential nutrients as minerals or carotenoids. Our results demonstrate that the most preferred colour by tortoises was the yellow, which might reflect carotenoid content, and we discuss the potential implications of this finding.

Factors affecting repatriation success of the endangered Italian agile frog ( Rana latastei )

Repatriations and translocations are among the most frequent actions deployed for conservation of amphibians all over the world. However, very few studies have analysed the effectiveness of these actions. The aims of this study were i) to measure the success of repatriations of Rana latastei carried out within a conservation project in Lombardy (Northern Italy) from 1999 to 2001, and ii) to analyse how the environmental factors affected repatriation success. Eighteen ponds were surveyed from February to April 2006, for an overall of 45 field surveys. Each pond was carefully checked for frogs and egg masses. We classified each pond as newly excavated or pre-existing according to habitat management actions and we measured 16 variables concerning micro- and macro-habitat characteristics, human disturbance and presence of predators. Rana latastei was found in 33.3% of monitored sites and the repatriation outcome of tadpole release did not differ between newly excavated and non managed ponds. Habitat variables influenced the success of repatriations, which increased in sites with higher percentage of woodlands. Finally, repatriation outcome was also negatively influenced by human disturbance and predator occurrence.