Hierophis Viridiflavus Research Articles

Melanin-based color variation in response to changing climates in snakes.

Melanism, the process of heavier melanin deposition, can interact with climate variation at both micro and macro scales, ultimately influencing color evolution in organisms. While the ecological processes regulating melanin production in relation to climate have been extensively studied, intraspecific variations of melanism are seldom considered. Such scientific gap hampers our understanding of how species adapt to rapidly changing climates. For example, dark coloration may lead to higher heat absorption and be advantageous in cool climates, but also in hot environments as a UV or antimicrobial protection mechanism. To disentangle such opposing predictions, here we examined the effect of climate on shaping melanism variation in 150 barred grass snakes (Natrix helvetica) and 383 green whip snakes (Hierophis viridiflavus) across Italy. By utilizing melanistic morphs (charcoal and picturata in N. helvetica, charcoal and abundistic in H. viridiflavus) and compiling observations from 2002 to 2021, we predicted that charcoal morphs in H. viridiflavus would optimize heat absorption in cold environments, while offering protection from excessive UV radiation in N. helvetica within warm habitats; whereas picturata and abundistic morphs would thrive in humid environments, which naturally have a denser vegetation and wetter substrates producing darker ambient light, thus providing concealment advantages. While picturata and abundistic morphs did not align with our initial humidity expectations, the charcoal morph in N. helvetica is associated with UV environments, suggesting protection mechanisms against damaging solar radiation. H. viridiflavus is associated with high precipitations, which might offer antimicrobial protection. Overall, our results provide insights into the correlations between melanin-based color morphs and climate variables in snake populations. While suggestive of potential adaptive responses, future research should delve deeper into the underlying mechanisms regulating this relationship.

Hemipenial morphology does not provide insight on mating barriers between the two main lineages of Hierophis viridiflavus (Lacépède, 1789)

Hemipenial morphology does not provide insight on mating barriers between the two main lineages of Hierophis viridiflavus (Lacépède, 1789)

First report of a prolonged bite by a Western Whip Snake, <i>Hierophis viridiflavus carbonarius</i> (Bonaparte 1833) (Serpentes, Colubridae), resulting in pronounced local oedema

Although extensive research has been conducted on snake venoms, the effects of bites inflicted by non-front-fanged colubroid snakes remain incompletely understood, particularly for species of uncertain medical relevance. The Western Whip Snake (Hierophis viridiflavus) is a colubrid snake typically classified as non-venomous and harmless to humans. Nevertheless, old works reporting the presence of Duvernoy's glands in this species raise questions regarding its presumed lack of venom. This report presents the first case of a prolonged bite from a wild Western Whip Snake (Hierophis viridiflavus carbonarius) that occurred in Italy, and provides a detailed account of the resulting effects. The primary symptom experienced by the bitten subject was painless, marked local oedema, which subsided within 24h after the bite. The clinical manifestations observed in the current study suggest that Hierophis viridiflavus could have the potential to inflict bites that lead to mild local effects consistent with envenoming.

Evolution of snake skin: Role of cutaneous tactile corpuscles in Hierophis viridiflavus (Lacépède, 1789)

AbstractThe skin of snakes acts as the first interface between these reptiles and the environment they live in. It plays an important role in the ecology of these organisms, and specialised structures, such as tactile corpuscles, are crucial in the sensing of a wide variety of stimuli. This study, by examining the presence, localisation and colocalisation of serotonin, substance P, PGP 9.5 and tubulin, wants to demonstrate the sensory role that these structures play in the ecology of the Green whip snake Hierophis viridiflavus (Lacépède, 1789). This study presents the first evaluation of nerve and immune molecules (TLR2) in the tactile corpuscles of H. viridiflavius ventral skin, indicating a potential defence role of these structures. These findings provide valuable information on the ecology of snakes, their defence systems, and their evolutionary morphostructural adaptations. Additionally, the identification of these corpuscles could provide valuable support for taxonomic recognition. Furthermore, this study expands the knowledge about stimuli sensing in snakes.

An extremely rare serovar of Salmonella enterica (Yopougon) discovered in a Western Whip Snake (Hierophis viridiflavus) from Montecristo Island, Italy: case report and review

Reptiles, including snakes, can be asymptomatically infected with multiple pathogen microorganisms, including Salmonella spp., which is considered an important concern for public and animal health. Small and uninhabited isles are quite ecologically different from mainland and represent interesting fields of study, to discover unexpected biological and microbiological aspects of their wild inhabitants. This work reports the presence of the very rare Salmonella enterica serovar Yopougon, isolated in a carcass of a native wild snake (Hierophis viridiflavus) from an Italian uninhabited island of Mediterranean Sea, Montecristo. To our knowledge, S. enterica serovar Yopougon was previously isolated only once 34 years earlier in Ivory Coast, from a human fecal sample. In the present study, we present the genomic characterization of the new isolate, the phylogenetic comparison with the previously isolated S. enterica serovar Yopougon strain of human origin and with other sequences available in public databases. In addition, an extensive review of available data in the literature and from our case history is provided. Our finding represents an example of the ability of some pathogens to travel for very long distances within their hosts and then to infect others, even from different taxa.

Confronting Habitat Requirements of Sardinian Populations of <i>Natrix maura</i> and <i>Hierophis viridiflavus</i> (Reptilia: Colubridae)

The habitat requirements of two snake species (Hierophis viridiflavus and Natrix maura) were studied in a hilly area of south-western Sardinia (Italy). At each sighting time, once a snake was observed, presence/absence data of 11 not-autocorrelated habitat/ecological variables were recorded, and the data were processed by logistic regression against a comparable number of random points. Presence of fruiting plants and of lizards were significantly positively correlated with the presence of Hierophis viridiflavus. Two variables, presence of water body and multiple fallen trees, were positively correlated with the presence of Natrix maura. The ecological correlates of these results are discussed in the present paper.

Extensive gene flow suggests lack of reproductive barriers between the two subspecies of the green whip snake, Hierophis viridiflavus (Squamata: Colubridae)

Abstract Speciation is the fundamental process that underlies the diversification of species. Different steps of speciation, such as reproductive isolation or ecological niche separation, can evolve in different orders and over different time scales. The two subspecies of the green whip snake, Hierophis viridiflavus viridiflavus and Hierophis viridiflavus carbonarius, sometimes considered as separate species, are ideal to study speciation because they diverged in isolated glacial refugia. So far, little is known about whether these two subspecies are reproductively isolated from each other. Furthermore, it is unknown whether the common melanism of the subspecies H. v. carbonarius might be genetically encoded. We quantified gene flow along two transects across the contact zone of the two subspecies using double-digest restriction site-associated DNA. Our analyses implicated the existence of two well-defined clades that experience substantial gene flow along a contact zone that is ~300 km wide. We detected a clear association between the genetic assignment and the quantitative extent of melanism within the contact zone, which is likely to be genetically polygenic. Given the level of gene flow, it seems that strong postzygotic reproductive barriers have not evolved. We conclude that the two subspecies represent evolutionarily significant units for conservation and suggest treating them taxonomically as subspecies.

Screening of Ophidiomyces ophidiicola in the free-ranging snake community annually harvested for the popular ritual of San Domenico e dei Serpari (Cocullo, AQ, Italy)

In the Abruzzi village of Cocullo (Italy), each year, on May 1st, local snake hunters (known as Serpari) display colubrids, captured in the wild, to commemorate the ancient ritual of San Domenico. The ascomycete Ophidiomyces ophidiicola (Oo) is the causative agent of ophidiomycosis, an emerging disease with sublethal effects. Skin lesions, such as dysecdysis, edematous, crusty or necrotic scales, swellings, nodules, and ulcers, are the most common clinical manifestation of the disease. The pathogen and its associated disease are well characterized in wild snakes in North America, whereas broad screenings of free ranging wild ophidians in Europe are rare. In 2019, as part of a multi-year snake health monitoring project, all the Cocullo ophidians were carefully examined for integumentary affections and those showing signs consistent with ophidiomycosis were dry swabbed on the skin and on any visible cutaneous lesions with a single applicator. The extracted DNA underwent a broad-range panfungal PCR targeting the D1-D2 region, as well as two conventional PCRs specific to the ITS2 and IGS regions of Oo DNA. Twenty-three out of 129 snakes (13/82 Elaphe quatuorlineata; 7/31 Hierophis viridiflavus; 3/15 Zamenis longissumus; 0/1 Natrix helvetica) resulted clinically affected, but no specific Oo genomic DNA was detected by PCR. The Cocullo ritual celebration provided a unique opportunity for the first systematic testing of a large sample size of a local snake community for the monitoring of this pathogen in Italy.

Phylogeographic and Paleoclimatic Modelling Tools Improve Our Understanding of the Biogeographic History of Hierophis viridiflavus (Colubridae).

Phylogeographic and paleoclimatic modelling studies have been combined to infer the role of Pleistocene climatic oscillations as drivers of the genetic structure and distribution of Mediterranean taxa. For the European whip snake, Hierophis viridiflavus, previous studies based on paleoclimatic modelling have depicted a low reliability in the pattern of past climatic suitability across the central Mediterranean Basin, which barely fits the species' genetic structure. In this study, we combined phylogeographic and paleoclimatic modelling tools to improve our understanding of the biogeographic history of H. viridiflavus, particularly extending the sampling and phylogeographic inferences to previously under-sampled regions. Phylogeographic analyses recovered two major clades that diverged at the beginning of the Pleistocene and had diversified in different ways by the late Pleistocene: the east clade (composed of three subclades) and the west clade (with no further structure). Paleoclimatic models highlighted the temperate character of H. viridiflavus, indicating range contractions during both the last inter-glacial and last glacial maximum periods. Range expansions from southern-located climatic refugia likely occurred in the Bølling-Allerød and Middle Holocene periods, which are supported by signals of demographic growth in the west clade and South-East-North subclade. Overall, this work improves our understanding of the historical biogeography of H. viridiflavus, providing further insights into the evolutionary processes that occurred in the Mediterranean Basin hotspot.

Intraspecific oophagy in Hierophis viridiflavus (Serpentes: Colubridae) during oviposition in a controlled environment


 
 
 
 Following the observation of adult pairs of the Western Whipsnake, Hierophis viridiflavus, in a controlled environment, two distinct but related phenomena were observed: egg deposition and predation of freshly laid eggs by the male. Data about deposition, number and morphology of the eggs, hatching and offspring are presented and compared with the literature. The episode of oophagy is described, confirming the inclination to predate snake eggs and intraspecific oophagy in this species.
 
 
 

Predation attempts on Hoopoe <i>Upupa epops</i> nests in a rural Mediterranean area of central Italy

Seventeen predation attempts on four Hoopoe Upupa epops nests in an heterogenous agricultural Mediterranean area of central Italy were recorded during breeding seasons 2020-21. Camera traps identified 7 different predators’ species, mainly Western whip snake Hierophis viridiflavus and Black rat Rattus rattus. Uropygial secretions and hissing calls from chicks and incubating female inside the breeding cavity always saved the clutches, while no active defense was performed by parents if outside the nest.

Large scale phenotypic characterisation of Hierophis viridiflavus (Squamata: Serpentes): climatic and environmental drivers suggest the role of evolutionary processes in a polymorphic species

Colour variability is largely widespread in the animal world as it is tightly associated with fitness and survivorship. Therefore, the drivers and implications of such variability have been of great interest for zoologists in the past decades. Reptiles are excellent models to investigate colour variations and expression under different conditions. Here, we focused on melanism occurrence in the two main lineages of Hierophis viridiflavus at the scale of the species distribution, by extracting available data from iNaturalist, a citizen science network, with the aim of detecting any pure effect of climate or local habitat on colour expression. Our analyses highlighted that habitat does not explain differences in phenotypes, whereas marked effects of geographic and climatic variables were detected. However, the observed climatic effects could be a proxy of the geographical distribution of the two groups, and thus the high occurrence of bright colourations in western populations of the eastern lineage could be addressed to an ongoing event of asymmetric gene flow in contact zones. The current distribution of phenotypes could be the outcome of the evolutionary history of the species combined with the geological history of the Mediterranean region. This investigation, though, is only preliminary and molecular analyses on highly variable regions of the genome are mandatory to address this issue.

Further evidence of ophiophagy, including cannibalism, by the western whip snake Hierophis viridiflavus in Italy

Further evidence of ophiophagy, including cannibalism, by the western whip snake Hierophis viridiflavus in Italy

Impact of invading species on biodiversity: Diet study of the green whip snake’s (Hierophis viridiflavus, L. 1789) in Switzerland

Next-generation sequencing is increasingly used in conservation biology to resolve complex interactions between species, either diet or gut parasites studies. We applied a recent long metabarcoding method to elucidate the green whip snake’s (Hierophis viridiflavus) prey consumption based on DNA extracted from stomach contents. Illegally introduced in Canton of Vaud (Switzerland), three populations of the green whip snake have strongly developed in two regions, East (Chablais) and North. We suspect that this introduced species is threatening part of the local herpetofauna, especially the Asp viper and the Western green lizard in this region. Consequently, an extermination program has been implemented from 2016 to mitigate Hierophis viridiflavus expansion and its impact arising from its generalist diet. Stomach contents of 94 individuals removed from introduction sites were analysed by long metabarcoding. Our study revealed the consumption of 67 prey belonging to 9 species, primarily small mammals and reptiles. The recurrent presence of two parasitic nematodes was also discovered. Although cannibalistic behaviour could not be highlighted with this approach, a scavenging behaviour was suspected based on the presence of an insect used in forensic entomology (Calliphora vicina). These results confirm the opportunistic feeding behaviour of Hierophis viridiflavus and its ability to predate on threatened species. Although 86.6 % of preys were not listed on the Swiss Red List, the impact on the Asp viper population can be important (up to 20 % of consumed preys) and could partially explain its strong decline.

How landscape and biotic interactions shape a Mediterranean reptile community

ContextDisentangling the effect of environment and biological interaction on community composition with observational data, within the environmental filtering framework, is challenging because the two processes produce non independent results.ObjectivesAdopting community N-mixture models with symmetric interactions, we aimed at estimating differential effects of landscape structure and biotic interactions on the local abundance of a Mediterranean reptile community including four lizards (Lacerta bilineata; Podarcis siculus; P. muralis; Chalcides chalcides) and two snakes (Hierophis viridiflavus; Natrix Helvetica).MethodsWe sampled reptiles for three consecutive years (2019–2021; 4 surveys/year) on 52 linear transects on a Mediterranean coastal landscape. We analyzed count data by means of a multi-species N-mixture model with symmetric interactions. Interactions within pair of species were estimated from the residual correlation of their realized abundances, after accounting for four landscape features: landscape heterogeneity calculated from land cover data, edge density of woody vegetation patches, tree cover density, net primary productivity.ResultsMost species displayed very low detection probability (p ~ 0.10). All species responded with different intensity and sensitivity to landscape predictors. Two biological interactions resulted significant: L. bilineata and P. siculus showed a positive interaction, while P. muralis and C. chalcides displayed a negative interaction.ConclusionsUsing community N-mixture models we demonstrated that, also with observational data obtained from a realized community, partitioning the filtering process of the landscape from the one of biotic interactions is possible.

Decision making under risk of predation in the western whip snake Hierophis viridiflavus

Decision making under risk of predation in the western whip snake Hierophis viridiflavus

Repeated use of high risk nesting areas in the European whip snake, Hierophis viridiflavus

Oviparous snakes deposit their egg clutches in sites sheltered from predation and from strong thermal and hydric fluctuations. Appropriate laying sites with optimum thermal and hydric conditions are generally scarce and are not necessarily localised in the home range. Thus, many gravid females undertake extensive trips for oviposition, and many may converge at the best egg laying sites. Dispersal mortality of neonates post-hatchling is also a critical factor. Assessing the parameters involved in this intergenerational trade-off is difficult however, and no study has succeeded in embracing all of them. Here we report data indicating that gravid females of the highly mobile European whip snake, Hierophis viridiflavus exhibit nest site fidelity whereby they repeatedly deposit their eggs in cavities under sealed roads over many decades. These anthropogenic structures provide benefits of relative safety and suitable incubation conditions (due to the protective asphalted layer?), but they expose both females and neonates to high risk of road mortality. Artificial laying sites constructed at appropriate distances from busy roads, along with artificial continuous well protected pathways (e.g. dense hedges) that connect risky laying sites to safer areas, should be constructed.

No association between candidate genes for color determination and color phenotype inHierophis viridiflavus,and characterization of a contact zone

Genetic and phenotypic differentiation in allopatric conditions can be explained either by neutral phenomena or adaptative processes driven by selection. In reptiles, coloration can affect aspects directly related to their survival, representing a classical character under selection. In this context, secondary contact areas are natural laboratory to understand evolutionary processes underlying genetic permeability, especially when populations differ in phenotypic traits such as coloration. The western whip snake Hierophis viridiflavus presents two divergent mitochondrial clades, characterized by the presence of one of two main color phenotypes, namely one with black and yellow stripes and a fully melanic one. Here, we investigated whether melanogenesis-linked genes are determinant of the chromatic differences observed across the phenotypic variation of the species. In addition, we used a multilocus dataset, including 134 original ND4 sequences, to better define the overall genetic structure and to provide a characterization of a contact zone identified in Central Italy by estimating the amount of nuclear gene exchange. While we found no evidence supporting a direct association between target genes and coloration, a non-synonymous substitution polymorphism, at high frequency, was detected in the β melanocyte-stimulating hormone whose possible function has been discussed. Concerning the genetic structure, both mtDNA and nuDNA were partly concordant indicating introgression events occurring at the contact zone. When we measured the nuclear gene flow, we found a significant amount of gene exchange, mainly guided from one clade to the other, that is, asymmetric. These results might suggest the presence of ecological and/or behavioral processes driving the observed directional gene flow.

Asynchrony of actuarial and reproductive senescence: a lesson from an indeterminate grower

AbstractEvolutionary theories relating to aging predict that patterns of actuarial and reproductive senescence should be aligned, with a common onset of senescence set at the age of first reproduction. However, a few empirical studies reported asynchrony between actuarial and reproductive senescence. This asynchrony is expected to be particularly pronounced in organisms with indeterminate growth. Yet, this process is still poorly documented due to the lack of long-term demographic data on known-aged individuals. We investigated the asynchrony of actuarial and reproductive senescence in the European whip snake, Hierophis viridiflavus, an oviparous colubrid with indeterminate growth. Using demographic data collected over a 29-year period, we showed that females did not experience any fecundity loss late in life. In contrast, they suffered from an early, severe actuarial senescence. Our findings thus revealed a pronounced asynchrony in actuarial and reproductive senescence processes, a phenomenon that could be widespread across the tree of life.

Snakes and the Eternal City: variation in community metrics, body size and population density of snakes in contrasted landscapes of suburban Rome (Italy)

Reports of global declines in animal populations are now numerous and also include snakes, a group of animals now widely regarded as bio indicators. A prerequisite for any conservation management plan to protect or restore snake populations requires a data base that provides insight into population composition and changes. However, snakes are well known to be particularly difficult to quantitatively sample due to their secretive and elusive nature, and hence accumulating an adequate database for analysis requires long-term field studies that involve intensive searches. Populations of four snake species, Zamensis longissimus, Natrix helvetica, Vipera aspis and Hierophis viridiflavus living in two suburban areas of Rome with different extents of habitat alteration (deforestation), Vejo, a less altered site, and Tor Bella Monaca, a high altered site, have been monitored, but with interruptions since 1995. The results indicated that H. viridiflavus was the commonest species at both sites. Male bias was found in all four species but especially in Z. longissimus and V. aspis with detection of juveniles greatest in H. viridiflavus and N. helvetica. Snout to vent lengths (SVL) of H. viridiflavus and Z. longissimus, which were present at both sites, were greater at the less degraded habitat of the two study localities. Community metrics indicated that the degraded habitat had lower species richness, evenness, Shannon and Simpson diversity indices, but a higher dominance index. Recapture frequencies of snakes recaptured either once or multiple times were in general greater at Vejo. The highest population densities were found in H. viridiflavus, followed by V. aspis and N. helvetica, which were similar. However, long term trends in densities show declines in V. aspis and N. helvetica between 1995 and 2019. Population densities were in good agreement with density estimates found in previous studies of snakes in more natural habitats.