Newt Triturus Vulgaris Research Articles

Initial orientation of newts (Triturus vulgaris, T. cristatus) following short– and long–distance displacements

Homeward orientation of smooth newts Triturus vulgaris and crested newts T. cristatus was measured following short– and long–distance passive displacement. Individuals were tested in arena experiments at release sites distributed symmetrically at 213–230 m distance (area of previous migratory experience) and at 2.225–3.270 km around the breeding pond. Newts were transported by car and had probably reduced access to outward journey information, but full access to local orientation clues at the release site during the night and early morning before testing. Within the area of migratory experience, the initial directional choice of both species was significantly directed to home. Outside the area of familiarity, the initial orientation was indistinguishable from random. This finding contradicts results obtained by other authors with a similar experimental design and using five distinct newt species. It remains to be tested to what degree differences among the results depend on the species used, on displacement distances, and/or on the geographic area.

Morphological integration of cranium and postcranial skeleton during ontogeny of facultative paedomorphic European newts (Triturus vulgaris and T. alpestris)

AbstractThe patterns of ontogenetic and interspecific variation of morphological integration (the relationships and correlation patterns of functionally and developmentally related morphological traits) in facultative paedomorphic species of two European newts (Triturus vulgaris and T. alpestris) were examined. The degree of morphological integration differed among ontogenetic stages. Variation in the level of morphological integration of cranium and postcranial skeleton during ontogeny of paedomorphic newts had the same pattern in both analysed species. The lowest level of cranium morphological integration characterises the larvae and the juveniles. Individuals that follow alternative life-history path (paedomorphs) remain at a relatively low level of morphological integration, while integration highly increased in metamorphosed adult individuals. Limb skeleton also showed a lower level of integration in paedomorphs in comparison with metamorphosed individuals. The hypothesis of morphological integration was confirmed for all stages of T. vulgaris, while the same hypothesis was confirmed only for larval and paedomorphic stages of T. alpestris. In T. vulgaris, metamorphosis changes the pattern of correlation among the cranial traits, while in T. alpestris, the patterns of phenotypic correlation among the cranial traits remain substantially similar for all analysed ontogenetic stages.

Distribution of amphibians and reptiles in central Poland: 1980-2000

Based on 3047 records from 97 recorders distribution maps were drawn for the amphibians and reptiles of central Poland (lirom 51°00’N to 52°15’N and from 18°20’E to 20°20’E). The study area was divided into 180 atlas fields based on the geographic grid. All data were gathered in 1980-2000, most of them (67%) however, in 1995-2000. 13 taxa of amphibians were found in 143 atlas fields and 6 species of reptiles were found in 121 atlas fields. The amphibians were (given with the number of atlas fields with the species found): 119 - Common frog Rana temporaria Linnaeus, 1758; 114 - Common toad Bufo bufo (Linnaeus, 1758); 97 - Moor frog Rana arvalis Nilsson, 1842; 94 - Fire-bellied toad Bomhina bombina (Linnaeus, 1761); 93 - Pool frog Rana lessonae Camerano, 1882; 87 - Tree frog Hyla arhorea (Linnaeus, 1758); 85 - Green toad Bufo viriiüs Laurenti, 1768; 72 - Smooth newt Triturus vulgaris (Linnaeus, 1758); 70 - Spadefoot Pelobales fuscus (Laurenti, 1768); 69 - Edible frog Rana kl. esculenia Linnaeus, 1758; 39 - Great crested newt Triturus cristatus (Laurenti, 1768); 30 - Marsh frog Rana ridibunda Pallas, 1771 and 28 - the Natterjack Bufo calamita Laurenti, 1768. The reptile species (given with the number o f atlas fields) were: 94 - Sand lizard Lacerta agilis Linnaeus, 1758; 72 - Slow-worm Anguis fragilis Linnaeus, 1758; 67 - Common lizard Lacerta vivipara Jacquin, 1787; 60 - Grass snake Natrix natrix (Linnaeus, 1758), 57 - Adder Vipera berus (Linnaeus, 1758) and 4 - the Smooth snake Coronella austriaca Laurenti, 1768. Six adult specimens of the European pond terrapin Emys orbicularis (Linnaeus) were also found, but breeding of this species in the area studied was not confirmed.

Triturus italicus: Analysis of lateralisation in the courtship behaviour

At the population level, male smooth newts (Triturus vulgaris) have a marked bias for left turning during spermatophore transfer behaviour. In a much more basal species of the genus, the Alpine newt, less than 50% of individuals show a significant left‐ or right‐side preference during courtship, whereas no lateral bias is found at population level. To verify whether the smooth newt's lateralised behaviour is a recent (apomorphic) acquisition, the degree of lateralisation during courtship displays occurring in another relatively more basal species (although less basal than T. alpestris), the Italian newt (T. italicus) was investigated. In the latter species, the analysis of the temporal structure of the sequences showed that males significantly utilised the same side during a single courtship sequence. However, 31% of the Italian newts showed a significant left‐ and 46% a right‐side preference. The presence of lateralisation in two relatively ‘primitive’ species (Alpine and Italian newt) at individual level only, with no evidence at population level, and the presence of a bias in a more derived species of the genus (T. vulgaris), support the hypothesis that population‐level lateralisation, in newts, is an independent autoapomorphic evolutionary event that took place in the smooth newt.

Foreword to Articles on IR Research

Since 1989 Inter-Research has been financially supporting and conducting research on the ecology and population dynamics of highly endangered local species. Our aim is to give back to nature a small fraction of wet grassland in Oldendorf/Luhe (Germany) that had suffered a near-lethal blow from human impact over decades, to re-introduce species which had originally inhabited that land and to support endangered ones. The dimensions of our efforts are modest. Our ‘Okologisches Versuchsgebiet’ or ‘Inter-Research Land’ presently occupies a total area of 5.5 hectare. Our staff, who does all the field and laboratory work, consists of 3 individuals working part time on the project: Otto Kinne, Jens Kunert and Waldemar Zimmermann. We have constructed 2 small field laboratories, built a variety of pools, ponds and ditches serving as reproduction areas, and provided summer and overwintering habitats. Our efforts have resulted in the successful reintroduction and building up of a small, viable field population of the fire-bellied toad Bombina bombina (total population strength estimated at ca. 80 individuals). We continue to breed the toad in the laboratory and to release juveniles into IR land, thus supporting the natural reproductive capacity of the field population. Similarly, we have re-introduced and built up a population of the warty newt Triturus cristatus. The total field population has already attained a quasi-natural age structure. It consists of an estimated 160 individuals. We continue laboratory breeding and raising, and make yearly additions to the field population by setting out larvae and/or juveniles. The less endangered smooth newt Triturus vulgaris is, at least since 1997, fully ‘self-sustaining’. In 1999 its local population numbered about 1300 individuals of different ages. ‘Inter-Research Land’ supports several other amphibians, reptiles, rare butterflies and birds, as well as several highly endangered plants, such as Stratiotes aloides.

Bony skull of the smooth newt Triturus vulgaris (Amphibia, Urodela: Salamandridae) and the role of thyroid hormones in its ossification.

Bony skull of the smooth newt Triturus vulgaris (Amphibia, Urodela: Salamandridae) and the role of thyroid hormones in its ossification.

Characteristics of development and ossification of skeletal elements in the limbs of the smooth newt Triturus vulgaris (Caudata).

Characteristics of development and ossification of skeletal elements in the limbs of the smooth newt Triturus vulgaris (Caudata).

Sexual size and shape dimorphism in two species of newts, Triturus cristatus and T. vulgaris (Caudata: Salamandridae)

AbstractMorphometric data from Fennoscandian populations of the crested newt Triturus cristatus and the smooth newt Triturus vulgaris were analysed for the presence of sexual size and shape dimorphism. The data sets included nine body‐related and nine head‐related measurements and were examined with univariate, bivariate and multivariate methods. Sexual dimorphism was demonstrated in both species. The separation of specimens was highly related to sex. Although the expression of sexual dimorphism differed between the two species, some patterns were shared. These are discussed in terms of evolution of intersexual dimorphism according to models of ecology, fecundity and sexual selection. In multivariate analyses, sexual dimorphism was restricted to body‐related variables such as standard length and distance of extremities (with high values for females), contrasting against cloaca and limb‐related characters (with high values for males). In both species, the ‘distance of extremities’ measure (i.e. trunk length) was one of the strongest sexually dimorphic traits. No evidence of sexual dimorphism in head morphology was found. The results are interpreted as primarily concordant with theories on fecundity selection. For example, it has been suggested that females with larger trunk volumes increase their reproductive capacity. The fact that males had longer extremities, in relation to other characters measured, could be attributed to sexual selection. Long limbs in male newts may be beneficial for courtship performance. Since head‐related characters did not show any patterns of sexual dimorphism, no evidence was found to suggest that male and female crested and smooth newts have adapted to different feeding strategies.

Sexual size and shape dimorphism in two species of newts, Triturus cristatus and T. vulgaris (Caudata: Salamandridae)

Morphometric data from Fennoscandian populations of the crested newt Triturus cristatus and the smooth newt Triturus vulgaris were analysed for the presence of sexual size and shape dimorphism. The data sets included nine body-related and nine head-related measurements and were examined with univariate, bivariate and multivariate methods. Sexual dimorphism was demonstrated in both species. The separation of specimens was highly related to sex. Although the expression of sexual dimorphism differed between the two species, some patterns were shared. These are discussed in terms of evolution of intersexual dimorphism according to models of ecology, fecundity and sexual selection. In multivariate analyses, sexual dimorphism was restricted to body-related variables such as standard length and distance of extremities (with high values for females), contrasting against cloaca and limb-related characters (with high values for males). In both species, the ‘distance of extremities’ measure (i.e. trunk length) was one of the strongest sexually dimorphic traits. No evidence of sexual dimorphism in head morphology was found. The results are interpreted as primarily concordant with theories on fecundity selection. For example, it has been suggested that females with larger trunk volumes increase their reproductive capacity. The fact that males had longer extremities, in relation to other characters measured, could be attributed to sexual selection. Long limbs in male newts may be beneficial for courtship performance. Since head-related characters did not show any patterns of sexual dimorphism, no evidence was found to suggest that male and female crested and smooth newts have adapted to different feeding strategies.

Body size, age and fecundity variation in different populations of the smooth newt Triturus vulgaris meridionalis in central Italy

Adult and larval body size, age distribution and female fecundity, traits related to fitness in the smooth newt Triturus vulgaris meridionalis, were compared in populations differing in water stability conditions in the area surrounding Rome, near the southern limit of the distribution of this subspecies. Larval body size varied among populations at the end of metamorphosis and was positively related to water stability conditions, which probably led to differences in adult body size. In populations of temporary ponds, age at first breeding was lowered to two years. Traits of female fecundity correlated positively with body size, but not with age. The Italian smooth newt adapted to the unpredictable environment by optimizing reproductive strategies such as the exploitation of the short wet period by means of early deposition of large eggs, which can produce large larvae at metamorphosis.

OBSERVATIONS OF PAEDOMORPHIC NEWTS (Triturus vulgaris) FROM THE FORMER SOVIET UNION

The reliable data on paedomorphosis in two subspecies of the common newt Triturus vulgaris lantzi (Abkhazia, western Caucasus) and T. v. vulgaris (the vicinity of St. Petersburg) are given for the first time for the former Soviet Union. Data on the appearance, occurrence, development and distribution of paedomorphic larvae are given based on field and laboratory observations beginning in 1986. The life cycles of paedomorphic and metamorphosed newts are discussed.

Modulation of the effect of arginine-vasopressin on water and ion transport in the newt early distal tubule and frog urinary bladder by V1-antagonists.

In the early distal tubule of the newt Triturus vulgaris L., 1 nM arginine-vasopressin (AVP) increased water reabsorption; the fractional reabsorption of Na+ was elevated from 46.2 +/- 6.9% to 67.8 +/- 3.9% (P < 0.001), of Cl- from 52.7 +/- 6.7% to 73.1 +/- 3.5% (P < 0.001), of Mg2+ from 48.0 +/- 7.7% to 71.7 +/- 6.3% (P < 0.001). When V1-receptors were blocked by 1 nM peptide V1-antagonist [1-(beta-mercapto-beta,beta-cyclopentamethylene propionic acid), 2-(O-methyl) Tyr]-[Arg8]vasopressin, 1 nM AVP increased the fractional reabsorption of fluid by 8.9% of Na+ by 10.7% and of Cl- by 11.2%, as compared with the effect of AVP alone. The fractional reabsorption of Ca2+ after addition of AVP did not differ from control; when V1-receptors were blocked in the presence of AVP, the fractional reabsorption of Ca2+ was increased by AVP. The V1-receptor block in the presence of AVP did not change the fractional reabsorption of Mg2+. Experiments on the urinary bladder of the frog Rana temporaria L. showed that 1 nM SR 49059, a non-peptide antagonist of V1a-receptors, like the peptide V1-antagonist, enhanced the AVP effect by 29%. Inhibition of protein kinase C activity by calphostin C (1 nM) mimicked the effect of V1-antagonists; the AVP hydroosmotic effect was increased by 60%. The results obtained indicate that V1-receptors modulate the effects of V2-receptor activation: their block is accompanied by an enhancement of the AVP hydroosmotic effect in the frog urinary bladder and by an increase of Na+ and Cl- reabsorption in the newt early distal tubule. The enhancement of the AVP effect owing to the V1-receptor activation seems to be mediated by a decrease in protein kinase C activity.

Gene flow rates in Yugoslavian populations of the smooth newt Triturus vulgaris

AbstractAllozymic variation in 22 loci in several Yugoslavian populations of four subspecies of the smooth newt Triturus vulgaris, has been analyzed. The frequency of private alleles and the coefficient of genetic differentiation, FST, give very different indirect estimates of the effective number of migrants per generation, Nm. However, such Nm estimates, in most cases higher than 1, imply that gene flow between populations is large enough as to prevent differentiation by random drift. In the case of T.v. vulgaris, of which sixteen populations amply distributed through Yugoslavia were sampled, there is evidence that frequent extinction and recolonization processes might be responsible for the observed genetic structure. This conclusion has been reached after testing the correlation between genetic, environmental and geographical matrices.

Predation on amphibian eggs and tadpoles by common predators in acidified lakes

Eggs and three different stages of premetamorphic tadpoles of moor frog Rana arvalis and common toad Bufo bufo were offered to the following potential predators in acidified lakes: newt Triturus vulgaris, water beetles Rhantus exoletus and Dytiscus lapponicus, dragonfly larvae Leucorrhinia dubia and Aeshna spp., water boatman Notonecta glauca and water bugs, Cymatia bonsdorffi, Glaenocorisa p. propinqua, and Corixa dentipes.The predation pressure on eggs of R. arvalis was low due to thick jelly. The eggs of B. bufo were not attractive to predators with chewing mouth parts due to unpalatability but predators with sucking mouth parts were not repulsed. Tadpoles of R. arvalis were eaten by all predators but tadpoles of B. bufo were unpalatable to most predators. The predators used in the experiments are the new top predators in acidified fishless lakes. They may contribute to the reduction of populations of R. arvalis in acidified areas.

The influence of furosemide and Co2+ on electrolyte and water transport in newt distal tubule and frog skin

The technique of stationary microperfusion of the early distal tubule used in experiments on male newts (Triturus vulgaris) revealed the intratubular effect of CoCl2 and furosemide on the ion transport. CoCl2 in concentration 5 X 10(-4) M increased Na and Cl reabsorption, reduced Ca, Mg and K reabsorption, and increased (TFexp/TFo)in from 1.14 +/- 0.04 to 1.68 +/- 0.27 (p less than 0.001). CoCl2 in concentration 5 X 10(-5) M enhanced Na and Cl reabsorption, without affecting transport of other ions. 6 X 10(-4) M furosemide decreased reabsorption of water, Na, Cl, Ca and Mg. The combined effect of Co2+ and furosemide inhibited reabsorption of Mg and Ca to a greater extent, but stimulated Na reabsorption. Experiments on frog skin showed that being added to the apical membrane of cells, Co2+ stimulates short circuit current and potential differences, whereas furosemide reducing Cl absorption induces only hyperpolarization. Experimental findings allow to assume that Co2+ on the outer surface of the apical membrane of the distal tubule cells blocks the selective Ca and Mg channels and activates Na channels.

Length polymorphism of rDNA indicates somatic alterations in the genome of Triturus vulgaris

We have analyzed the EcoRI restriction pattern of ribosomal genes (rDNA) isolated from several organs of single individuals of the newt Triturus vulgaris by Southern blotting and hybridization with corresponding Xenopus probes (r11 and r12). Using length polymorphism of rDNA spacers as a molecular marker, it became evident that in individual newts the pattern of ribosomal genes is not always constant but varies between different tissues of the same animal suggesting the occurrence of genome alterations during ontogenesis.

Cumulative Effect of Male's Displays in the Sexual Behaviour of the Smooth Newt Triturus vulgaris (Urodela, Salamandridae)1

AbstractThe relevance of the temporal spacing of signals to the timing and nature of the receiver's response during a communicative process was studied in the sexual behaviour of the smooth newt Triturus vulgaris. The possibility that a high rate of stimulation allows an accumulation of the effects of successive signals was investigated by comparing sexual interactions leading and not leading to spermatophore deposition.Results showed that the difference between the two types of interactions lay only in temporal features of the stimulation provided by the male to the female. Females, although in a comparable initial state of receptivity and exposed to comparable amounts of stimulation, performed the act triggering spermatophore deposition by the male only in some interactions. Display bouts, in which the male displayed at short intervals (less than 4 s), were longer in interactions where spermatophore deposition took place than in the others. This suggests that courtship was effective if accumulation of the effects of male displays could occur. This proposition was supported by the observation of a progressive change in the immediate female response to a given male display in the group where courtship bouts were longer.Our results indicate the existence of a system of tonic communication (see Schleidt 1973) during the sexual behaviour of the smooth newt, in which the effects of the male displays accumulate over time until some critical threshold is reached in the female.

Are there insertions in the ribosomal DNA of vertebrates?

We have analysed the Eco RI restriction pattern of rDNA of the newt Triturus vulgaris and of some other amphibian species by Southern blotting and hybridization with nick-translated Xenopus rDNA prepared from the recombinant plasmids pXlr11 and pXlr12 (21). After hybridization with r11, the 28S coding fragments become visible in two bands, a prominent one of 5.3 kb and a weak band of 5.9 kb representing about 8% of the 28S genes. The evidence obtained so far by additional digestions with Bam HI and Bgl II indicates that in this species and in Triturus helveticus the coding regions of the 5.9 kb fragments are interrupted by an insertion 0.6 kb in length located in a 1.6 kb Bgl II fragment at the 3' end of the Eco RI fragment, which we believe to be the first described in a vertebrate.

Metabolism of C19-steroids in testicular tissue of the newtTriturus vulgaris, during and after breeding

Incubation studies with testicular homogenates ofTriturus vulgaris showed that testosterone was quantitatively the most important metabolite of dehydroepiandrosterone and androstenedione during breeding. After breeding the recovery of testosterone declined. This suggests that 17β-hydroxysteroid dehydrogenase may be regulated for the needs of testicular androgen production.

Studies on the natural predators of Culex pipiens L. and C. torrentium Martini (Diptera: Culicidae) in England

AbstractThe natural predators of Culex pipiens L. and C. torrentium Mart, in artificial containers and ponds were studied in southern England, using serological techniques. The antisera were from rabbits immunised by injections of saline extracts of the species of Culex into the inguinal lymph nodes and made relatively more specific by absorption. The gut contents or whole individuals of 1098 potential predators were smeared on to filter paper and tested. The most important predators in the ponds were Odonata nymphs while those of artificial containers were larval Dytiscidae. Diptera and Araneae preyed on emerging adults. The length of time a mosquito meal remained detectable in the gut of predators varied from a minimum of 8 h for the newt Triturus vulgaris to 24 h for the zygopteran Ischnura elegans (van der Linden). The results of laboratory tests indicated that the anisopteran Sympetrum striolatum (Charp.) was potentially more important as a biological control agent for larval culicines in ponds than the zygopteran Coenagrion puella (L.).