Vipera Aspis Research Articles

Unusual “erythroid loops” in canine blood smears after viper‐bite envenomation

Northern Italy is a habitat for many species of viper; Vipera aspis is responsible for most reported bites of humans and animals. Five dogs of different breeds and ages were presented by their owners to a veterinary clinic in northern Italy between September 2004 and August 2007 with a history of being bitten by a viper within the past 2 hours. On physical examination, all of the dogs were depressed, had pale mucous membranes, and had a painful area consistent with a recent viper bite wound on the nose (2), distal front leg (2), or lip (1). Hemoglobinemia and hemoglobinuria were observed in plasma and urine from all dogs. CBCs were done at the time of presentation, daily for 4 days, and 10 days after presentation in all dogs with the exception of one dog that died after 2 days. All dogs had an acute decrease in HCT within 24 hours of presentation; all dogs had neutrophilia, 3/5 had a mildly toxic left shift, and 4/5 had thrombocytopenia. On Diff-Quik-stained blood smears, moderate numbers of echinocytes, spherocytes, and erythrocyte ghosts were observed. In addition, moderate numbers of unusual erythrocyte membrane-like structures ("erythroid loops") were observed. The loops were annular in shape and sometimes disrupted, appearing as thin pale blue bands. Erythrocyte morphologic abnormalities decreased by day 3 and were no longer observed on day 10. The unique appearance of the erythroid loops together with evidence for intravascular hemolysis and other erythrocyte morphologic changes suggest they may be a consequence of erythrocyte lysis. Echinocytes, spherocytes, and erythrocyte ghosts are known to result from the action of phospholipase in viper venom; however, erythroid loops have not been reported previously and their exact mechanism of formation is unknown.

Molecular phylogeography of the asp viper Vipera aspis (Linnaeus, 1758) in Italy: Evidence for introgressive hybridization and mitochondrial DNA capture

Owing to its temperature dependence and low vagility, the asp viper ( Vipera aspis) is an interesting model species to study the effects of Pleistocene climatic fluctuations on vertebrate genomes. We genotyped 102 specimens from the whole Italian distribution range at three mitochondrial DNA regions (2278 characters, total) and six microsatellite DNA loci (Short Tandem Repeats, STR). The molecular phylogeny was constructed according to Bayesian, Neighbour Joining, Maximum Parsimony and Maximum Likelihood procedures. All methods grouped individuals of the three morphological subspecies ( V. a. aspis, V. a. francisciredi, V. a. hugyi) into five different haploclades. Specimens assigned to hugyi clustered in two highly differentiated clades, one being sister group to the complex comprising the second clade of hugyi (i.e., a paraphyletic status), plus two clades of francisciredi. The Bayesian clustering of the STR variability disclosed only two groups, the first including aspis and francisciredi, the second all hugyi. Introgressive hybridization and capture of francisciredi-like lineages in the hugyi mitochondrial genome were suggested to explain the discordance between mitochondrial and nuclear data. The phylogeographic pattern was compatible with population contractions in three glacial refuges. Plausibility of derived hypothesis was checked using coalescence simulations as post hoc tests. Long-term drift and serial founder effects, rather than selection, appeared the main factors affecting the genetic make-up of the Italian asp viper.

Geographic variation of body size and reproductive patterns in Continental versus Mediterranean asp vipers, Vipera aspis

The occurrence of variation in body size and reproductive traits of Vipera aspis was assessed by analysing 74 reproductive females of different populations, collected throughout a large part of the distribution range of the taxon, from central-western France to central Italy. Six populations were analysed, two of plain habitats, in France and Italy, characterized by a Continental climate, whereas the other four derived from two coastal and two inland, hilly Italian habitats, respectively, showing a Mediterranean climate. Females of the French area showed the smallest mean body size, whereas the pre- and post-partum body masses of females from the coolest, central Italic area were significantly higher. Litter size varied among habitats and was significantly correlated with maternal body size. If the snout-vent length feature varied largely among offspring of different habitats (with the longest size occurring in representatives of the coastal, central Italian area), the average of both body mass and total mass of offsprings did not exhibit any clear pattern among populations colonizing different habitats. Nevertheless, relative litter mass was higher in the French continental populations, and lower in the coolest, Mediterranean, Italian ones. It is worth emphasizing the positive correlation between the snout-vent length feature of females and the total litter mass to environmental factors, such as hottest month temperature and total rainfall. The available literature records that female body size affects offspring size and fecundity. If the present study bolsters this correlation, it also rules out any other effect of female body size on the offspring characteristics analysed. Finally, evidence is provided for the role of climatic factors on life-history traits (e.g. pre-partum body mass) of asp vipers, although confounding effects pursued, for example, by food availability may occur.

Disappearance of eggs during gestation in a viviparous snake ( Vipera aspis ) detected using non-invasive techniques

th August. Abstract. The number of eggs released at ovulation may be greater than the number of offspring born, if some of these ovulated eggs and/or embryos disappear during ges - tation. Although this process can potentially exert significant effects on reproductive output, logistical problems have discouraged studies on the disappearance of eggs and embryos in most kinds of vertebrates. Nuclear Magnetic Resonance (NMR) imaging and ultrasound Doppler-imaging have not been applied previously to such questions. Using these techniques, we monitored changes in the female's oviduct through gestation in a viviparous snake. We documented a case of disappearance of two ovulated eggs (from a litter of four) in the aspic viper, Vipera aspis. The female ovulated four normal- sized eggs, two of which contained living embryos when examined by NMR and ultra - sound Doppler-imaging early in gestation. Subsequent NMR imaging midway through gestation showed the same situation, but a third imaging session immediately prior to parturition revealed that the oviducts contained only the two live embryos. The two nonviable eggs had disappeared. The female gave birth to the two live offspring, with no evidence of any additional material. These data thus offer the strongest evidence so far available for egg disappearance (resorption?) during gestation in reptiles. More gen - erally, NMR imaging offers a valuable tool for investigating processes inside the body cavity, where direct observation is otherwise difficult or impossible. The technique does not require sacrifice of the animals, and hence allows dynamic investigations over time.

Diet of the asp viper Vipera aspis in woodland habitats of the Po plain (NW Italy)

The diet of Asp viper Vipera aspis was studied in forested habitat of Northern Italy The species feeds on a low number of preys, possibly reflecting the reduction of small mammal richness in woodland habitats.

SUBCUTANEOUS ABSCESS DUE TO PSEUDOMONAS AERUGINOSA IN CAPTIVE ASP VIPER ( VIPERA ASPIS )

SUMMARY Abscesses are one of the most frequent clinical ent ities of the captive snakes (Hoppmann and Wilson Barron, 2006). In contrast with the mammals, the reptilian purulent material is caseous, forming hard “cheese-like” plu gs that are nearly impenetrable to antibiotics, making the key to successful treatment of the reptilian abscesses the complete removal of the abscess cavity and surrounding fibro us capsule (Mader, 2006). Many causes are found for abscesses; foreign bodies embedded, p arasites (Mihalca et al., 2007), fungi and bacteria (Kobolkuti and Czirjak, unpublished data) can lead to the formation of the exudates. Bacteria from the genus Pseudomonas are part of the normal flora of the oral cavity and intestinal tracts of the snakes (Blaylock, 2001; Ko bolkuti and Czirjak, unpublished data). Often they are considered opportunistic pathogens, causing different clinical diseases under the stress of the captivity. A case of subcutaneous abscess was described at a c aptive asp viper ( Vipera aspis ). During the examination, the snake showed a well localized 3 cm x 1 cm abscess with a central stub-like scar. After the local anesthesia, all the parts of the abscess were surgically removed. Pseudomonas aeruginosa was isolated in monoculture from the pus and ident ified as casual agent of infection . Based on antibiograme we started a treatment using Enrofloxacin generally (10mg/kgc i.m.). After 5 days of antibiotic and pos t-surgical treatment, the recovery of the animal was 100%. To our knowledge this is the first described case o f Pseudomonas infection in captive asp viper ( Vipera aspis ).

PCR-sequence characterization of new adenoviruses found in reptiles and the first successful isolation of a lizard adenovirus

A consensus nested PCR was used to screen diagnostic samples from approximately 70 reptiles for the presence of adenoviruses (AdV) in the years 2006–2007. Classical virus isolation methods were also used with all samples. After adenoviruses were detected in a group of helodermatid lizards in a Danish zoo, a follow-up study was also carried out on lizards from this group (10 Mexican beaded lizards and 24 Gila monsters) over the period of a year. Adenoviruses were detected in a total of 26 lizards and snakes by PCR. The PCR amplicons from all positive animals were sequenced and the resulting polymerase gene sequences were used for phylogenetic analysis. Altogether six Agamid AdVs were amplified, with a minimal sequence variation between one another and between these and GenBank Agamid AdVs. The sequence obtained from one of the Gila monsters is identical with the GenBank Helodermatid AdV, while the sequences from the Mexican beaded lizards differ from this. In a snake collection we have detected a new AdV from an Asp viper. All of the above mentioned adenoviruses cluster in the Atadenovirus genus. However, the sequence from a new Varanid AdV detected in this study clusters outside this genus. On cell culture, viruses were isolated from three of the AdV positive helodermatid lizards (one Mexican beaded lizard and two Gila monsters) and identified as AdVs based on electron microscopy and PCR and sequencing using cell culture supernatant. This is the first report of the successful isolation of a lizard AdV.

GIS‐based niche models identify environmental correlates sustaining a contact zone between three species of European vipers

ABSTRACTThe current range of European vipers is mostly parapatric but local‐scale allopatric distribution is common and few cases of sympatry are known. In the High Course of Ebro River, northern Spain, there is a contact zone between Vipera aspis, V. latastei, and V. seoanei. Sympatry was detected between aspis and latastei and also specimens with intermediate morphological traits. Presence‐data at a local scale (1 × 1 km) and ecological niche‐based models manipulated in a GIS were used to (1) identify how environmental factors correlate with the distribution of the three vipers and with the location of the sympatry area, and (2) identify potential areas for viper occurrence and sympatry. Ensemble for casting with 10 Maximum Entropy models identified a mixture of topographical (altitude, slope), climatic (precipitation, evapotranspiration, and minimum and maximum temperature), and habitat factors (land cover) as predictors for viper occurrence. Similar predicted probabilities according to the variation of some environmental factors (indicating probable sympatry) were observed only for aspis‐latastei and aspis‐seoanei. In fact, areas of probable occurrence of vipers were generally allopatric but probable sympatry between vipers was identified for aspis‐latastei in 76 UTM 1 × 1 km squares, for aspis‐seoanei in 23 squares, and latastei‐seoanei in two squares. Environmental factors correlate with the location of this contact zone by shaping the species range: some enhance spatial exclusion and constrain distribution to spatially non‐overlapping ranges, while others allow contact between species. The distribution in the contact zone apparently results from the balance between the pressures exerted by the different environmental factors and in the sympatry area probably by interspecific competition. Further ecological and genetical data are needed to evaluate the dynamics of the probable hybrid zone. GIS and niche‐modelling tools proved to be powerful tools to identify environmental factors sustaining the location of contact zones.

Albinism and Leucism Among European Viperinae: a Review

The records of albino, partial albino, and leucistic individuals among four species of European Viperinae ( Vipera ammodytes , Vipera aspis , Vipera seoanei , and Vipera berus ) were summarized based on literature records, museum material, reports of field herpetologists and herpetoculturists, and a short description of all reported specimens was made. For the first three species only scattered observations have been made (1, 1, and 6 reports), whereas at Vipera berus these defects proved to be more widespread (16 reports), and present an occurrence pattern shift to the Nordic countries. Different hypotheses are postulated on the offset geographic distribution pattern of albinism and leucism at this species, taking into account the differences in predation pressure and population densities between populations in Southern and Northern Europe. The possible negative effect of the color defects on the fitness and survival of the specimens carrying them is debated.

Reappraisal of Vipera aspis Venom Neurotoxicity

BackgroundThe variation of venom composition with geography is an important aspect of intraspecific variability in the Vipera genus, although causes of this variability remain unclear. The diversity of snake venom is important both for our understanding of venomous snake evolution and for the preparation of relevant antivenoms to treat envenomations. A geographic intraspecific variation in snake venom composition was recently reported for Vipera aspis aspis venom in France. Since 1992, cases of human envenomation after Vipera aspis aspis bites in south-east France involving unexpected neurological signs were regularly reported. The presence of genes encoding PLA2 neurotoxins in the Vaa snake genome led us to investigate any neurological symptom associated with snake bites in other regions of France and in neighboring countries. In parallel, we used several approaches to characterize the venom PLA2 composition of the snakes captured in the same areas.Methodology/Principal FindingsWe conducted an epidemiological survey of snake bites in various regions of France. In parallel, we carried out the analysis of the genes and the transcripts encoding venom PLA2s. We used SELDI technology to study the diversity of PLA2 in various venom samples. Neurological signs (mainly cranial nerve disturbances) were reported after snake bites in three regions of France: Languedoc-Roussillon, Midi-Pyrénées and Provence-Alpes-Côte d'Azur. Genomes of Vipera aspis snakes from south-east France were shown to contain ammodytoxin isoforms never described in the genome of Vipera aspis from other French regions. Surprisingly, transcripts encoding venom neurotoxic PLA2s were found in snakes of Massif Central region. Accordingly, SELDI analysis of PLA2 venom composition confirmed the existence of population of neurotoxic Vipera aspis snakes in the west part of the Massif Central mountains.Conclusions/SignificanceThe association of epidemiological studies to genetic, biochemical and immunochemical analyses of snake venoms allowed a good evaluation of the potential neurotoxicity of snake bites. A correlation was found between the expression of neurological symptoms in humans and the intensity of the cross-reaction of venoms with anti-ammodytoxin antibodies, which is correlated with the level of neurotoxin (vaspin and/or ammodytoxin) expression in the venom. The origin of the two recently identified neurotoxic snake populations is discussed according to venom PLA2 genome and transcriptome data.

Heterodimeric neurotoxic phospholipases A 2—The first proteins from venom of recently established species Vipera nikolskii: Implication of venom composition in viper systematics

For the first time the venom of recently established viper species Vipera nikolskii was fractionated and two heterodimeric phospholipases A 2 (HDP-1 and HDP-2) were isolated. Isolation of HDP-1 and HDP-2 is the first indication of the presence of two heterodimeric phospholipases A 2 in the venom of one viper species. When tested on the frog neuromuscular junction, isolated proteins affected neuromuscular transmission acting presynaptically. Using RP-HPLC, each heterodimer was separated into two monomeric subunits: basic phospholipase A 2 (HDP-1P and HDP-2P) and acidic component without enzymatic activity (HDP-In). The complete primary structures of subunits were deduced from corresponding sequences of cDNAs. The determined amino acid sequences were homologous to those of vipoxin from Vipera ammodytes and vaspin from Vipera aspis. Similar proteins were not found earlier in the well-studied venom of Vipera berus, the species from which V. nikolskii was recently separated. Our finding supports at the biochemical level the correctness of the establishment of V. nikolskii as an independent species. The finding of similar proteins (HDPs and vipoxin) in geographically remote species ( V. nikolskii and V. ammodytes) corroborates the hypothesis about the pre-existence of genes encoding these proteins in all true viper species and their expression under certain conditions.

Ecological Relationships between Sympatric Vipera Aspis and Vipera Ursinii in High-Altitude Habitats of Central Italy

The ecological relationships between two sympatric vipers (Vipera aspis and Vipera ursinii) were studied at a mountainous area in central Italy (Gran Sasso, Abruzzo), between spring 2004 and autumn 2006. The two species differed significantly in their altitudinal distribution: V. ursinii being confined to the higher elevations (above 1650 m elevation), and V. aspis being present from the lowest to the highest altitudes (1200-1900 m). We recorded a wide sector of approximately 250 m elevation (between 1650 and 1900 m elevation) where the two species overlapped. In these areas, the two species exhibited significant difference in microhabitat use and diet composition. Male and female V. aspis were larger (SVL) than male and female V. ursinii. Furthermore, the two species exhibited a significant difference in sexual size dimorphism, with females being larger than males in V. ursinii, whereas no such difference in SVL was observed in V. aspis. However, we did not observe any difference in SVL of male and female vipers when comparing sympatric and allopatric populations. Overall, the potential for competition between these two species appears to be low because of their clearly different realized ecological niches. The ecology of European vipers has received considerable interest since the pioneering stud- ies conducted by Saint Girons (1952, 1978, 1980). Some European viperids (notably Vipera berus) are currently among the ecologically best known snake species in the world (e.g., Madsen, 1988; Madsen and Stille, 1988; Madsen and Shine, 1992a). However, most studies have focused on the population biology of a single species (e.g., Madsen and Shine, 1992b, c), whereas comparatively few studies have ex- plored the population biology of sympatric populations (for a review, see Luiselli, 2006a). The first study on the ecology of sympatric viper populations was a field study on Vipera aspis and V. berus in Western France (Saint Girons, 1975). After this pioneer study, only a few detailed studies have been conducted, the most significant being those on sympatric V. aspis and V. berus populations in the mountains of Switzerland (Monney, 1996) and on sympat- ric Vipera seoanei and Vipera latastei populations in the northwestern Iberian peninsula (Brito and Crespo, 2002; Martinez et al., 2006). In general, these studies suggest that sympatric vipers tend to partition the habitat niche axis to minimize competition, whereas their diets and activity patterns are very similar (Luiselli, 2006a). However, much still needs to be known concerning the ecological relationships of sym- patric European viper populations to further test competition/niche partitioning issues and also to explore conservation implications of threatened species/populations. In this paper, we describe the ecological relationships be- tween two viper species, the European Asp (V. aspis) and the Meadow Viper (Vipera ursinii), in a mountainous area of central Italy. The Meadow Viper is an endangered species which inhabits a few scattered mountain peaks in Western Europe (Bruno, 1985; Bombi et al., 2006).

Directional asymmetry and correlation of tail injury with left-side dominance occur in Serpentes (Sauropsida)

Recent evidence on directional asymmetry (DA) in species of the paraphyletic assemblage “Lacertilia” indicates a possible biological significance of this phenomenon, and we tested its occurrence in Serpentes by examining bilateral morphological characters, such as the numbers of supralabial and infralabial scutes and the diameter of the eyes, on both sides of museum specimens of seven species: Coronella austriaca, Elaphe longissima, Hierophis viridiflavus, Natrix natrix, Natrix tessellata, Platyceps saharicus, and Vipera aspis. Significant DA (not antisymmetry) occurred in at least one sex of four species and in two characters: H. viridiflavus—the number of infralabial scutes in males; N. tessellata—the diameter of the eyes in males; P. saharicus—the number of infralabial scutes in males and the diameter of the eyes in females; and V. aspis—the number of infralabial scutes in the pooled sexes. In N. tessellata and P. saharicus the DA varied geographically. Rank correlation between the DA of different characters, positive or negative, was significant in one character pair in each of three species. In the largest sample (N. tessellata males from the Levant), tail injury correlated with morphological left-dominant asymmetry (a greater number on the left) of infralabial scutes. Four of ten morphologically left-dominant males, but only 1 of 37 symmetrical or right-dominant males, had an injured tail. The syndrome of morphological DA with functional handicap may be genotypical or phenotypical. Our results support three earlier conclusions: bilateral characters should be examined on both sides of an animal; asymmetry should be analyzed separately in each sex; and the accident proneness of left-handed Homo sapiens merits re-evaluation in view of the apparently wide-spread accident proneness in left-biased Sauropsida (exclusive of Aves).

The postnatal development of the optic nerve of a reptile (Vipera aspis): a quantitative ultrastructural study

The number of axons in the optic nerve of the ovoviviparous reptile Vipera aspis was estimated from electron micrographs taken during the first 5 weeks of postnatal life. One to two days after birth, the optic nerve contains about 170,000 fibres, of which about 9% are myelinated. At the end of the fifth postnatal week, the number of optic fibres has fallen to about 100,000, of which about 42% are myelinated. This fibre loss continues after the fifth postnatal week, since in the adult viper the nerve contains about 60,000 fibres, of which 85% are myelinated; overall, about 65% of the optic nerve fibres present at birth disappear before the number of axons stabilises at the adult level. This study shows, for the first time, that the mode of development of the visual axons of reptiles is not that of anamniote vertebrates but similar to that of birds and mammals.

The karyology of Vipera aspis, V. atra, V. hugyi, and Cerastes vipera

AbstractIn the current paper we show the results obtained using standard and banding staining methods (Ag-NOR-, CMA3-, C-banding and sequential colorations (or Alu I digestions) + CMA3 + DAPI) in specimens of Cerastes vipera, Vipera aspis, V. atra, and V. hugyi. Cerastes vipera presented chromosomal characters, primitive in snakes, as a karyotype of 2n = 36 chromosomes, with 16 biarmed macrochromosomes and 20 microchromosomes, NORs on one microchromosome pair and absence of cytologically evident sex chromosomes, at least with the methods used. The three taxa of Vipera studied showed chromosomal characters either derived, or primitive or at an initial stage of differentiation. All three species showed a karyotype (derived) of 2n = 42 chromosomes with 22 macro- and 20 micro-chromosomes; they all showed NORs on one micro-chromosome pair and presented Z and W chromosomes at an initial stage of differentiation. Sexchromosomes Z and W, were in fact homomorphic, but the former was near all euchromatic, while the W chromosome was almost completely heterochromatic. All the three taxa of Vipera resulted, however, karyologically diversified, mainly due to the number of macro-chromosomes pairs with a centromeric, CMA3 positive heterochromatin: almost all the pairs in V. aspis, two pairs in V. atra and absent in V. hugyi.

Null models, co-occurrence patterns, and ecological modelling of a Mediterranean community of snakes

AbstractA Mediterranean community of snakes, inhabiting a hilly area in central Italy (Monterano, Tolfa Mountains) was statistically modelled to investigate whether: (i) it shows non-random structure as predicted by competition theories, (ii) there are proximate elements of the landscape that may predict the presence/absence of the various snake species at the study area, and (iii) the snakes select 'resting sites' which are relatively simple or relatively complicated in landscape structure. To investigate issue (i) we used co-occurrence pattern analyses and Monte Carlo simulations. To investigate issue (ii) we used logistic regression analysis on presence/absence data of eleven 'proximate landscape' variables around sites of presence for the snakes and around random (= absence) sites at the same study area. To investigate issue (iii), we used expected-versus-observed χ2 to test whether snake presences were associated more often than random with a combination of variables, i.e. with at least four different variables for each point of presence. The snake community was constituted by eight species, but only the five commonest species (i.e. Coluber viridiflavus, Elaphe longissima, Elaphe quatuorlineata, Natrix natrix, and Vipera aspis) were included in our models. Our modeling and simulation analyses suggested that: (i) the community structure was not competitively structured both in terms of habitat resource and in terms of 'proximate landscape' variables influencing snake presences; (ii) all five snake species were positively influenced by at least two of the eleven variables considered in the logistic regression model; (iii) four out of five species clearly selected sites with complicated structure, the only exception being Coluber viridiflavus.

First helminthological data on Iberian vipers: Helminth communities and host-parasite relationships

AbstractEuropean vipers are ambush predators with sporadic feeding events, thereby maintaining the digestive tract empty for long periods. According to previous studies relating lizards’ dietary habits and their helminth faunas, we predict poor gastrointestinal helminth communities in vipers. To test this hypothesis, we have examined the digestive tract of 86 specimens of Vipera aspis (L., 1758) and V. latastei Boscá, 1878, from several localities of the Iberian Peninsula. We found adults of only two nematode species Kalicephalus viperae (Rud., 1819) and Ophidascaris sp. and cysts adhering to the external wall on the stomach in case of two other nematode species Ascarops strongylina (Rud., 1819) and Spirurida gen. sp. All these nematodes are common parasite species in snakes, although Ophidascaris sp. has never before been recorded in Vipera sp. The low prevalence and small number of parasite species in Iberian vipers matched their low feeding rates. However, our results contrast with studies in Poland and Belarus of V. berus species, in which nematodes, as well as trematodes, are common and abundant. Rainfall rates are lower in the Iberian Peninsula than in eastern Central Europe, where amphibians are more available and consumed by V. berus. Amphibians, intermediate hosts for these helminths, have been recorded only sporadically as prey for V. aspis and V. latastei, thus supporting the absence of trematodes in both Iberian viper species. Among populations of Iberian vipers, the prevalence of parasites correlates with the feeding rate (i.e. percentage of vipers with prey), suggesting a linkage between the two parameters. In conclusion, our results suggest that several factors, including climatic characteristics of localities, feeding rates of predators, and type of prey consumed, influence the number and type of parasites in Iberian vipers.

Phylogeography of the asp viper ( Vipera aspis) inferred from mitochondrial DNA sequence data: Evidence for multiple Mediterranean refugial areas

a Laboratoire de Biologie de la Conservation, Departement d’Ecologie et Evolution, Bâtiment de Biologie, Universite de Lausanne, CH-1015 Lausanne, Switzerland b School of Biological Sciences, University of Wales, Bangor LL57 2UW, Wales, UK c Cultural Foundation Elapsoidea, CH-1219 Aire/Geneva, Switzerland d Centre de Coordination pour la Protection des Amphibiens et des Reptiles de Suisse, KARCH, CH-3005 Berne, Switzerland e Museo di Storia Naturale e del Territorio, Universita di Pisa, Via Roma 79, I-56011 Calci, Italy f 805 Rue du Pre de l’Ane, F-73000 Chambery, France g Saury, F-74210 La Tuile, France

Winter weather affects asp viper Vipera aspis population dynamics through susceptible juveniles

Winter weather affects asp viper Vipera aspis population dynamics through susceptible juveniles

Winter weather affects asp viper Vipera aspis population dynamics through susceptible juveniles

Detailed studies on mammals and birds have shown that the effects of climate variation on population dynamics often depend on population composition, because weather affects different subsets of a population differently. It is presently unknown whether this is also true for ectothermic animals such as reptiles. Here we show such an interaction between weather and demography for an ectothermic vertebrate by examining patterns of survival and reproduction in six populations of a threatened European snake, the asp viper (Vipera aspis), over six to 17 years. Survival was lowest among juvenile and highest among adult snakes. The estimated annual probability for females to become gravid ranged from 26% to 60%, and was independent of whether females had reproduced in the year before or not. Variation in juvenile survival was strongly affected by winter temperature, whereas adult survival was unaffected by winter harshness. A matrix population model showed that winter weather affected population dynamics predominantly through variation in juvenile survival, although the sensitivity of the population growth rate to juvenile survival was lower than to adult survival. This study on ectothermic vipers revealed very similar patterns to those found in long-lived endothermic birds and mammals. Our results thus show that climate and life history can interact in similar ways across biologically very different vertebrate species, and suggest that these patterns may be very general.