Differences in Ecological and Genetic Adaptations between Salamandra infraimmaculata and Ommatotriton vittatus

Israel is home to two species of amphibians belonging to distinct genera: Salamandra and Ommatotriton. They inhabit various regions, sometimes coexisting and in other instances dwelling separately across different areas, making their segregation challenging. This study compares the biological, ecological, and genetic traits of two species, the Near Eastern fire salamander Salamandra infraimmaculata and the southern banded newt Ommatotriton vittatus, to determine why O. vittatus thrives in a wider range of semi-arid habitats in central and southern Israel, whereas S. infraimmaculata predominantly occupies the coastal Mediterranean region in the north. Salamander larvae are typically found in streams, freshwater springs, and cave pools, whereas newt larvae inhabit winter pools and ponds exclusively. The developmental phase of salamander tadpoles extends over several months, whereas newt tadpoles spend a comparatively brief period in the water, from 1 to a few months. Notably, genetic disparities in the cytochrome b sequence in Israeli populations are more pronounced among newts than salamanders.

The Yellow Spot Pattern of Salamander (Salamandra infraimmaculata) in Various Habitats at the Southern Border of Its Distribution in Israel

The present study describes the different color-pattern phenotypes of yellow spots on the black back of Salamandra infraimmaculata in various habitats at the southern border of its distribution in Israel. At Tel Dan, we photographed 454 salamanders in moist habitats where water flows year round;100 of these were sampled to measure the percentage of yellow and black color on the back, and the number of spots on the head. At Kibbutz Sasa, 201 salamanders were photographed, of which 62 were sampled for the measurements. In Kibbutz Yehiam, 200 salamanders were photographed, and 60 were sampled for the measurements. At all sites, about a third of the salamanders were photographed more than once. For all three populations, yellow spots on the salamander back were found in one row, two rows or scattered. For two indices (proportion of yellow/black and number of spots on the head), the Dan population (under wet, running water all year round conditions) differed from the two other populations of salamanders (under semi-arid mountain conditions). The number of yellow spots on the head of the salamanders in the three populations varied from 1 to 7. In all populations, 4 spots pattern was the most common. In the Dan population, there were significantly more salamanders with 1 to 3 spots on their head than in the Sasa or Yehiam populations. No difference was found in the number of head spots for Sasa vs. Yehiam salamanders. The percentage of yellow on the black back was significantly larger for the Dan salamanders vs. the two other populations. The main question examined was whether there is an effect of the habitat conditions in isolated populations on the spot pattern on the salamander back. The answer is positive and is supported by previous studies.

Ecological, Biological and Genetic Adaptation to Xeric Habitats of <i>Salamandra infraimmaculata</i>on the Southern Border of Its Distribution

In the present mini-review, published and unpublished data that have been collected for more than 40 years on the adaption of Salamandra infraimmaculata to semi-arid environments on the southern border of its distribution are presented. The contribution of the present paper is in building a model based on comparing moist habitats with predictable and relatively constant conditions to semi-arid habitats with relatively dry conditions. Based on these parameters, the model suggests adaptation to semi-arid habitats. More specifically, this model is based on the morphology, biology, behavior, life cycle and physiology of S. infraimmaculata adaptation. By considering these many parameters, one hypothesis was raised and was supported. The adaptation to and selection of semi-arid habitats depend mainly on the terrestrial phase and very little on the aquatic phases. In all of the semi-arid habitats, there are various breeding places where the larvae can grow and complete metamorphosis. The molecular genetic variation among the various areas supports our hypothesis, and the difference in the moist habitats is greater than in the semi-arid environments.

Genetic Variation in <i>Salamandra</i><i>infraimmaculata</i>from Different Habitats Using Amplified Fragment Length Polymorphism

The purpose of the present study was to examine the genetic variation in Salamandra infraimmaculata from different breeding site habitats using the Amplified Fragment Length Polymorphism (AFLP) method. The results of the dendogram from a hierarchical cluster analysis show that the grouping of S. infraimmaculata as cluster 5 differs from all the other clusters, including the St1 (Tel-Dan stream) population, which was the most predictable. Five Haplogroups (Hg) were characterized. The mean number of alleles per locus in each population (Ne) ranged from 10.566 (Sp1) to 2.720 (Po6). An average estimated heterozygosity (He) by population ranged from 0.100 (Po6) to 0.186 (St1). Population St1, a permanent breeding site where water was available all year round, exhibited the highest level of polymorphism, while population Po6, from the ephemeral breeding site, exhibited the lowest level of polymorphism. Gene flow between clusters showed that clusters 3 and 4 are sources of migrants and also receive gene flow, while clusters 1 and 2 may be a source of migrants but may not receive much gene flow. A phylogenetic analysis, based on clustering using Nei’s genetic distance, demonstrated that the Tel-Dan population is located on a separate branch within its sub-population. The conclusion of the present study shows that the genetic divergence among isolated populations is not correlated to distance but is affected by the variation of habitats.

Cannibalism, among Other Solutions of Adaption, in Habitats Where Food Is Not Available for Salamandra infraimmaculata Larvae Diet in Breeding Places in Xeric Habitats

The present study examines the inherent flexibility in the feeding responses of S. infraimmaculata larvae to various breeding places. In addition, the study examines the hypothesis that in dry conditions, the water breeding places are the limiting factor for the survival and completion of the life cycle of populations of S. infraimmaculata. In the breeding sites, the food for larvae is not available, and cannibalism is the specific adaptation for larvae to grow and complete metamorphosis. S. infraimmaculata larvae feed on various invertebrates in different habitats, and cannibalism involves the adaptation to breeding places where food is not available. The growth only by cannibalism as the only way to adapt to these habitats because no food is found in breeding places at the southern border of its distribution is described here for the first time, not only in salamanders but in other animals as well.

Damage to <i>Salamandra infraimmaculata</i>Populations by Human Activity in Creating Water Pits Is a Death Trap in Semi-Arid Habitats

The different breeding sites of Salamandra infraimmaculata on the southern border of its distribution were examined and mapped in order to estimate the damage caused by water holes that could represent death traps for salamanders in xeric habitats. Among the various types of breeding sites (springs, streams, water holes, winter pools and reservoirs), the larvae of salamanders were detected in high numbers in springs and streams (503) and water holes (48), and in relatively low numbers in winter pools. Two water holes were examined in detail to estimate the damage caused to S. infraimmaculata where breeding places are limited. During the winter, both males and females enter a water hole for breeding. The percentage of males in and around the water hole was 42% and that of females 29%. After the salamanders’ oviposition in the water, they try to return to terrestrial habitats, but are unable to do so and lose weight and die. The body mass index (BMI) of salamanders decreases from winter (December) after they move to the water hole to spring (April), when they are found in the water hole. The estimation of potential damage is about 300 mature salamanders annually.

Slow and steady wins the race: contrasted phylogeographic signatures in two Alpine amphibians

A deeper phylogeographic structure is expected for slow-dispersing habitat specialists compared to widespread adaptable species,especially in topographically complex regions.We tested this classic assumption by comparing the genomic(RAD-sequencing)phylogeographies of 2 amphibians inhabiting the Swiss Alps:the mobile,cosmopolitan common frog(Rana temporaria)against the stationary,mountain endemic Alpine salamander(Salamandra atra).Our results ran opposite of predictions:the frog displayed significantly higher genetic divergences and lower within-population variation compared to the salamander.This implies a prominent role for their distinctive glacial histories in shaping intraspecific diversity and structure:diversification and recolonization from several circum-Alpine micro-refugia for the frog versus a single refugium for the salamander,potentially combined with better population connectivity and stability.These striking differences emphasize the great variability of phylogeographic responses to the Quaternary glaciations,hence the complexity to predict general patterns of genetic diversity at the regional scale,and the forces that underlie them.

Toxin variation among salamander populations:discussing potential causes and future directions

Amphibians produce defensive chemicals which provide protection against both predators and infections.Within species,populations can differ considerably in the composition and amount of these chemical defenses.Studying intraspecific variation in toxins and linking it to environmental variables may help us to identify the selective drivers of toxin evolution,such as predation pressure and infection risk.Recently,there has been a renewed interest in the unique toxins produced by salamanders from the genus Salamandra:the samandarines.Despite this attention,intraspecific variation has largely been ignored within Salamandra-species.The aim of this study was to investigate whether geographic variation in profiles of samandarines exists,by sampling 4 populations of Salamandra atra over its range in the Dinaric Alps.In addition,we preliminary explored whether potential variation could be explained by predation(counting the number of snake species)and infection risk(cultivation and genomic analyses of collected soil samples).Salamanders from the 4 populations differed in toxin composition and in the size of their poison glands,although not in overall toxin quantity.Nor predation nor infection risk could explain this variation,as populations barely differed in these variables.Sampling over a much broader geographic range,using better estimators for predation and infection risk,will contribute to an improved understanding of how environment may shape variation in chemical defenses.Nevertheless,as the 4 populations of S.atra did differ in their toxin profiles,we propose that this species provides an interesting opportunity for further ecological and evolutionary studies on amphibian toxins.