Geographic variation of life-history traits in the sand lizard, Lacerta agilis: testing Darwin's facundity-advantage hypothesis

The fecundity-advantage-hypothesis (FAH) explains larger female size relative to male size as a correlated response to fecundity selection. We explored FAH by investigating geographic variation in female reproductive output and its relation to sexual size dimorphism (SSD) in Lacerta agilis, an oviparous lizard occupying a major part of temperate Eurasia. We analysed how sex-specific body size and SSD are associated with two putative indicators of fecundity selection intensity (clutch size and the slope of the clutch size-female size relationship), and with two climatic variables throughout the species range and across two widespread evolutionary lineages. Variation within the lineages provides no support for FAH. In contrast, the divergence between the lineages is in line with FAH: the lineage with consistently female-biased SSD (L. a. agilis) exhibits higher clutch size and steeper fecundity slope than the lineage with an inconsistent and variable SSD (L. a. exigua). L. a. agilis shows lower offspring size (egg mass, hatchling mass) and higher clutch mass relative to female mass than L. a. exigua, i.e. both possible ways to enhance offspring number are exerted. As the SSD difference is due to male size (smaller males in L. a. agilis), fecundity selection favouring larger females, together with viability selection for smaller size in both sexes, would explain the female-biased SSD and reproductive characteristics of L. a. agilis. The pattern of intraspecific life-history divergence in L.agilis is strikingly similar to that between oviparous and viviparous populations of a related species Zootoca vivipara. Evolutionary implications of this parallelism are discussed

Molecular data confirm recent fluctuations of northern border of dice snake (Natrix tessellata) range in Eastern Europe

Herein we present the cytochrome oxidase subunit I (COI) based phylogeography of the dice snake (Natrix tessellata) in Eastern Europe and The Balkans. Eight haplotypes were identified. Phylogenetic reconstruction has showed 3 major clades: 1) Greece, 2) Balkans, Central and Eastern Europe, 3) Eastern Europe (Ukraine and Russia only). Our data are in concordance with the results of other studies of the species' phylogeography. The northernmost isolated population of the dice snake in Lipetsk province, Russia have no differences from neighboring Ukrainian populations and seems to be the result of recent colonization during the Holocene climatic optimum.Ministry of education and science of Republic of Serbia [173025

Molecular data confirm recent fluctuations of northern border of dice snake (Natrix tessellata) range in Eastern Europe

Herein we present the cytochrome oxidase subunit I (COI) based phylogeography of the dice snake (Natrix tessellata) in Eastern Europe and The Balkans. Eight haplotypes were identified. Phylogenetic reconstruction has showed 3 major clades: 1) Greece, 2) Balkans, Central and Eastern Europe, 3) Eastern Europe (Ukraine and Russia only). Our data are in concordance with the results of other studies of the species' phylogeography. The northernmost isolated population of the dice snake in Lipetsk province, Russia have no differences from neighboring Ukrainian populations and seems to be the result of recent colonization during the Holocene climatic optimum.Ministry of education and science of Republic of Serbia [173025

Variation in body size and sexual size dimorphism in the most widely ranging lizard: testing the effects of reproductive mode and climate

Reproductive mode, ancestry, and climate are hypothesized to determine body size variation in reptiles but their effects have rarely been estimated simultaneously, especially at the intraspecific level. The common lizard (Zootoca vivipara) occupies almost the entire Northern Eurasia and includes viviparous and oviparous lineages, thus representing an excellent model for such studies. Using body length data for >10,000 individuals from 72 geographically distinct populations over the species' range, we analyzed how sex‐specific adult body size and sexual size dimorphism (SSD) is associated with reproductive mode, lineage identity, and several climatic variables. Variation in male size was low and poorly explained by our predictors. In contrast, female size and SSD varied considerably, demonstrating significant effects of reproductive mode and particularly seasonality. Populations of the western oviparous lineage (northern Spain, south‐western France) exhibited a smaller female size and less female‐biased SSD than those of the western viviparous (France to Eastern Europe) and the eastern viviparous (Eastern Europe to Far East) lineages; this pattern persisted even after controlling for climatic effects. The phenotypic response to seasonality was complex: across the lineages, as well as within the eastern viviparous lineage, female size and SSD increase with increasing seasonality, whereas the western viviparous lineage followed the opposing trends. Altogether, viviparous populations seem to follow a saw‐tooth geographic cline, which might reflect the nonmonotonic relationship of body size at maturity in females with the length of activity season. This relationship is predicted to arise in perennial ectotherms as a response to environmental constraints caused by seasonality of growth and reproduction. The SSD allometry followed the converse of Rensch's rule, a rare pattern for amniotes. Our results provide the first evidence of opposing body size—climate relationships in intraspecific units

Roitberg_et_al_svl_data

Data for adult body size (snout-vent length, SVL) Abbreviations of characters/columns (if not clear from their designations): No, this column is for technical purposes of the author; No_inv, inventary number (in the museum or in the working protocols of the primary researcher); ssp, subspecies/clade: 1 L. a. agilis, 3 L. a. exigua; reg3, code of the study sample as in Roitberg et al., 2015, Table 1; sta, "stages": ad adult, gr gravid, m junger adult, sub subadult, j (=juv) juvenile; NB: subadults and juveniles, as well as unsexed individuals, were excluded from all analyses in Roitberg et al. 2015; sex: 1 males, 2 females, 3 unsexed; Num , individual (study subject) number in the author's extended data base. filter_adults: 1 individuals considered as "adults" in Roitberg et al. (2015), 2 other individuals. Abbreviations of museums: mkhar, Museum of Nature, Kharkiv National Karazin University; mkiev, National Museum of Natural History Kyiv; mtd, Senckenberg Natural History Collections Dresden; zfmk, Zoological Research Museum A. Koenig Bonn; zmb, Humboldt Natural History Museum Berlin; zmh, Zoological Museum Hamburg; zsm, Zoological State Collections Munich. Comment 1. The codes “mkhar” and “mkiev” do not represent established abbreviations of the corresponding museums and used for simplicity. Comment 2. This data table does not include Sample 3 (South Sweden) and Sample 9 (Russia, Ciscaucasia 1) because for these samples we used published mean values (respectively, Olsson, 1988 and Ushkalova, 1976). Comment 3. SVL-values for Sample 4 (Poland) were obtained by extracting log(SVL)-values from published scatterplots (Borczyk & Paśko, 2011: Fig. 1, A,B) and subsequent re-calculating the raw values using the exponent function. Comment 4. SVL-values for Sample 10 (Russia, Ciscaucasia 2) and Sample 11 (Russia, Ryazan Region) were obtained from published histograms (respectively, Lukina, 1966: Fig. 22 and Zharkova, 1973: Fig. 4). Comment 5. SVL-values for the other samples are original data of the authors

Variation of Reproductive Traits and Female Body Size in the Most Widely-Ranging Terrestrial Reptile: Testing the Effects of Reproductive Mode, Lineage, and Climate

The European common lizard, Zootoca vivipara, is the most widespread terrestrial reptile in the world. It occupies almost the entire Northern Eurasia and includes four viviparous and two oviparous lineages. We analysed how female snout-vent length (SVL), clutch size (CS), hatchling mass (HM), and relative clutch mass (RCM) is associated with the reproductive mode and climate throughout the species range and across the evolutionary lineages within Z. vivipara. The studied variables were scored for 1,280 females and over 3,000 hatchlings from 44 geographically distinct study samples. Across the species range, SVL of reproductive females tends to decrease in less continental climates, whereas CS corrected for female SVL and RCM tend to decrease in climates with cool summer. Both relationships are likely to indicate direct phenotypic responses to climate. For viviparous lineages, the pattern of co-variation between female SVL, CS and HM among populations is similar to that between individual females within populations. Consistent with the hypothesis that female reproductive output is constrained by her body volume, the oviparous clade with shortest retention of eggs in utero showed highest HM, the oviparous clade with longer egg retention showed lower HM, and clades with the longest egg retention (viviparous forms) had lowest HM. Viviparous populations exhibited distinctly lower HM than the other European lacertids of similar female SVL, many of them also displaying unusually high RCM. This pattern is consistent with Winkler and Wallin’s model predicting a negative evolutionary link between the total reproductive investment and allocation to individual offspring

Inter-observer and intra-observer differences in measuring body length: a test in the common lizard, Zootoca vivipara

Abstract. The snout-vent length (SVL), a conventional measure of overall body size in lizards and snakes, is used in a wide variety of ecological, evolutionary, and taxonomical studies. Trends in SVL variation are often analysed using data from several researchers (observers), but possible confounding effects due to inter-observer differences in measurement protocols have never been appropriately examined. This study reports inter-observer biases between eleven herpetologists who measured the same specimens of the Eurasian common lizards (21 adult specimens were examined by eight observers and additional 192 specimens by two observers). Intra-observer bias over time (1.5-15 months between measuring sessions) was also estimated. In the vast majority of comparisons, mean difference between the first author and another observer varied from −1.0 to +0.8 mm, or from −1.9 to +1.6 % if expressed as a percent of the specimen’s SVL value. Some non-regular effects of sex and study sample on the studied bias were revealed, and their possible reasons are discussed. We are advising the researchers who intensively collect SVL and other morphometric data to consider testing intra-observer and inter-observer biases and to establish etalon samples available for re-examinations