Search results for "Vipera"

Antipredatory function of head shape for vipers and their mimics.

2011

Most research into the adaptive significance of warning signals has focused on the colouration and patterns of prey animals. However, behaviour, odour and body shape can also have signal functions and thereby reduce predators' willingness to attack defended prey. European vipers all have a distinctive triangular head shape; and they are all venomous. Several non-venomous snakes, including the subfamily Natricinae, commonly flatten their heads (also known as head triangulation) when disturbed. The adaptive significance of this potential behavioural mimicry has never been investigated. We experimentally tested if the triangular head shape typical of vipers offers protection against predation.…

Evaluating the potential for evolutionary mismatch in Batesian mimics: A case study in the endangered smooth snake (Coronella austriaca)

2018

Many harmless organisms gain a survival advantage by mimicking venomous species. This is the case of the endangered smooth snake (Coronella austriaca), which mimics venomous vipers. Although this may protect the smooth snake against most of its natural predators, it may render them at greater risk of mortality from humans, who are more inclined to kill species, such as vipers, that they consider dangerous. This may cause an evolutionary mismatch, whereby humans may counteract the natural advantage of mimicry. We explore this possibility of evaluating the willingness of humans to kill smooth snakes versus the adder (Vipera berus), as well as their ability to discern them in the Åland Islands…

Protective coloration of European vipers throughout the predation sequence

2020

Antipredator adaptations in the form of animal coloration are common and often multifunctional. European vipers (genus Vipera) have a characteristic dorsal zigzag pattern, which has been shown to serve as a warning signal to potential predators. At the same time, it has been suggested to decrease detection risk, and to cause a motion dazzle or flicker-fusion effect during movement. We tested these hypotheses by asking whether (1) the zigzag pattern decreases detection risk and (2) the detection is dependent on the base coloration (grey or brown) or the snake's posture (coiled, basking form or S-shaped, active form). Additionally, (3) we measured the fleeing speed of adders, Vipera berus, an…

Significance of the dorsal zigzag pattern of Vipera latastei gaditana against avian predators

2005

Summary 1. Aposematism is an antipredatory strategy in which prey animals conspicuously signal their noxiousness to potential predators. This successful strategy is based on avoidance learning of predators. 2. Most species in the viperid genus Vipera have a characteristic dorsal zigzag pattern. It has previously been suggested that the dorsal zigzag pattern of Vipera berus (the adder) has a cryptic function and thus makes the snake less conspicuous to avian predators. However, a recent experiment suggested that the pattern may function as an aposematic signal rather than being cryptic, and therefore induces active avoidance in avian predators. 3. We conducted a field experiment in Donana na…

Warning signalling in European vipers and their mimics : implications for conservation of the smooth snake

2014

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

2006

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., …

Resembling a Viper: Implications of Mimicry for Conservation of the Endangered Smooth Snake

2014

The phenomenon of Batesian mimicry, where a palatable animal gains protection against predation by resembling an unpalatable model, has been a core interest of evolutionary biologists for 150 years. An extensive range of studies has focused on revealing mechanistic aspects of mimicry (shared education and generalization of predators) and the evolutionary dynamics of mimicry systems (co-operation vs. conflict) and revealed that protective mimicry is widespread and is important for individual fitness. However, according to our knowledge, there are no case studies where mimicry theories have been applied to conservation of mimetic species. Theoretically, mimicry affects, for example, frequency…

Ophiophagy in Coronella austriaca: first case of predation on Hierophis viridiflavus and first direct observations of predation on Vipera aspis

2020

We describe some cases of ophiophagy behaviour in Coronella austriaca

Vipera aspis hugyi (Southern Italian Asp) Coloration

2020

We report the first observation of concolor coloration in Vipera aspis hugyi

Antipredatory Function of Head Shape for Vipers and Their Mimics

2011

Most research into the adaptive significance of warning signals has focused on the colouration and patterns of prey animals. However, behaviour, odour and body shape can also have signal functions and thereby reduce predators' willingness to attack defended prey. European vipers all have a distinctive triangular head shape; and they are all venomous. Several non-venomous snakes, including the subfamily Natricinae, commonly flatten their heads (also known as head triangulation) when disturbed. The adaptive significance of this potential behavioural mimicry has never been investigated. We experimentally tested if the triangular head shape typical of vipers offers protection against predation.…