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

Abstract

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.

Shelter availability, stress level, and digestive performances in the aspic viper

“…Previous studies provided important background (Saint Girons, 1957;Bonnet et al, 1999;Bonnet et al, 2000;Bonnet et al, 2001;Bonnet et al, 2002;Bonnet, 2011;Ladyman et al, 2003;Zuffi et al, 2009;Michel and Bonnet, 2010). Aspic vipers [Vipera aspis (Linnaeus 1758)] feed mainly on rodents and digestion is impeded when body temperature falls below 15°C (Naulleau, 1983).…”

Contrasted Thermal Regimes Do Not Influence Digestion and Growth Rates in a Snake from a Temperate Climate

“…Snout-to-vent length (SVL) for mean adult body size is approximately 55 cm, and body mass averages 100 g (Naulleau 1997). Field and captivity studies provide backgrounds on life cycle, growth rate, and reproduction (Saint Girons 1957Girons , 1978Naulleau 1975Naulleau , 1979Naulleau , 1983Naulleau and Bonnet 1996;Bonnet et al 1999bBonnet et al , 2000Bonnet et al , 2003Zuffi et al 1999Zuffi et al , 2009). In the distribution area of the aspic viper, ambient temperature fluctuates between Ϫ20.0ЊC and 45.0ЊC, generating important variations of T b (Naulleau 1997).…”

Reproductive traits of the gray ratsnake Ptyas korros from three geographically distinct populations

“…As ectotherms, reptiles are highly dependent on environmental conditions, making them very attractive subjects for studying environmentally induced variation in life-history traits Niewiarowski et al, 2004;Shine, 2005). Reptiles with wide distributional ranges often display geographical variation in life-history traits (Iverson et al, 1993;Shine, 2000;Zuffi et al, 2009;Tanaka and Mori, 2011;Wang et al, 2011). Such variation reflects partly genetic divergence caused by natural selection as the consequence of adaptive responses to local environments, and partly the proximate effects of environmental factors such as temperature and food availability (Shine, 2005).…”

“…In snakes, for example, of some 3000 extant species (Greene, 1997) data gathered from two or more populations have been reported for only a handful of taxa, including several colubird, e.g., Elaphe carinata (Qu et al, 2011), E. quadrivirgata (Tanaka and Mori, 2011), E. taeniura Du and Ji, 2008), Storeria dekayi (Kofron, 1979;King, 1993), Thamnophis proximus (Tinkle, 1957;Clark, 1974;Lancaster and Ford, 2003) and T. sirtalis (Burt, 1928;Dunlap and Lang, 1990), elapid, e.g., Cacophis squamulosus (Shine, 1980) and Naja atra (Ji and Wang, 2005), and viperid, e.g., Crotalus viridis oreganos Wallace, 1984, 2002), Vipera aspis (Zuffi et al, 2009) and V. berus (Andrén and Nilson, 1983;Madsen and Shine, 1994). Datasets describing geographic variation in life-histories from more species across multiple taxonomic groups are needed to eluci-date the general patterns and/or to determine the mechanisms that result in unique patterns Niewiarowski et al, 2004;Shine, 2005).…”