Cristina Giacoma

A multivariate analysis of amphibian habitat determinants in north western Italy

The distribution of Bufo bufo, Rana esculenta complex, Rana dalmatina, Hyla arborea, Triturus carnifex and Triturus vulgaris were studied in 61 ponds in NW Italy, in relation to a number of specific habitat features. Multivariate analysis identifies those habitat parameters which classify ponds into characteristic habitat groups. Several multivariate statistical tests were carried out to identify habitat features characteristic of each species and to delineate ecological factors that influence amphibian distributions and size of breeding populations. Variables scored at each pond were: extent of aquatic vegetational cover, age of the pond, terrestrial habitats occurring near the ponds, degree of human interference, surface areas, maximum depth, chemical water factors (such as pH and water hardness). The first four of these parameters influenced breeding population presence of R. dalmatina, H. arborea, T. vulgaris and T. cristatus significantly. Densities of H. arborea, R. dalmatina, B. bufo and R. esculenta were apparently unaffected by any of these parameters; these species seem to colonize available habitats almost at random.

Prolactin and sexual behaviour in the crested newt (Triturus cristatus carnifex Laur.)

Abstract In an attempt to elucidate the possible prolactin involvement in sexual behaviour in the male crested newt, we have devised three experimental approaches: (1) hypophysectomy followed by replacement therapy with prolactin; (2) ectopic pituitary autograft; and (3) treatment with ergocryptine. After hypophysectomy (1), the percent time spent in courtship falls rapidly and is restored partially only by exogenous prolactin. In the short-term ectopic pituitary autograft (2), the enhanced release of endogenous prolactin triggered by the operation exerts a stimulatory effect on sexual behaviour. Courtship behaviour declines in the subsequent days. In long-term operated animals, spermatophore deposition is suppressed and concurrent testes regression takes place. After ergocryptine treatment (3), the percent of time spent in courtship decreases and is restored partially by exogenous prolactin. Hence prolactin appears to control sexual behavior in the crested newt, although other hormones seem to be involved in this mechanism. The occurrence of a synergism between prolactin and gonadal hormones in sustaining sexual behaviour in the crested newt is suggested. The action of prolactin on peripheral organs also is discussed.

Reproductive Investment of Female Green Toads (Bufo viridis)

Abstract Females of iteroparous species may compromise between contrasting reproductive strategies. They should balance the amount of energy devoted to reproduction against the energy saved for growth and survival, and they should compromise between the quantity versus the quality of offspring. In the present paper, we analyze these trade-offs in European Green Toads (Bufo viridis). We define reproductive investment in terms of clutch dry mass, number of eggs, and mean ovum dry mass, whereas we describe the amount of resources saved for growth and survival (somatic investment) with a fat index derived from the total body electrical conductivity (TOBEC) of postspawning females. Our results indicate that larger individuals produce larger clutches, both in the number and size of eggs. Females with higher reproductive effort, however, also show a larger somatic investment regardless of size. We show that females of similar size invest similar proportions of resources in reproduction, so that those in good condition not only show larger reproductive effort than lower-quality females but also store larger amounts of resources for growth, survival, and future reproduction.

Quantitative acoustic analysis of the vocal repertoire of the crowned lemur

Only a preliminary qualitative description of the vocal repertoire of Eulemur coronatus is available and no quantitative study of the calls of any wild or captive crowned lemur has ever been performed. The aim of this study was to verify whether the categories of calls in the crowned lemurs vocal repertoire briefly described on qualitatively bases by Macedonia & Stanger (1994) correspond to discrete phonetic categories. Through all-occurrence and focal animal observations, we recorded the vocal activity of 37 crowned lemurs housed in five institutions, both in Europe and Madagascar. We measured both temporal and spectral properties to describe calls quantitatively. We extracted acoustic parameters in the perspective of the source-filter theory of sound production. From spectrograms, we measured call duration and 6 larynx-related features and, using Linear Predictive Coding spectra, we measured four vocal tract related acoustic properties. From a preliminary qualitative inspection of the spectrograms, we identified the 12 types of vocalizations previously described by Macedonia & Stanger (1994) and partially by Petter & Charles-Dominique (1979). Our quantitative analysis has statistical support for a clear classification of 10 acoustic types: Long Grunt, Long Grunt Clear Call, Grunted Hoot, Grunt, Snort, Click, Hoot, Alarm Call, Tonal Call and Scream. In particular, cross-validated Discriminant Function Analysis successfully classified a high percentage of the vocal signals in the 10 vocal categories. Acoustic cues of both larynx-related and vocal tract-related acoustic parameters also offered preliminary support for both sex and individual identity potential that should be more thoroughly investigated in future studies.

Effects of nautical traffic and noise on foraging patterns of Mediterranean damselfish (Chromis chromis).

Chromis chromis is a key species in the Mediterranean marine coastal ecosystems where, in summer, recreational boating and its associated noise overlap. Anthropogenic noise could induce behavioural modifications in marine organisms, thereby affecting population dynamics. In the case of an important species for the ecosystem like C. chromis, this could rebound on the community structure. Here, we measured nautical traffic during the summer of 2007 in a Southern Mediterranean Marine Protected Area (MPA) and simultaneously the feeding behaviour of C. chromis was video-recorded, within both the no-take A-zone and the B-zone where recreational use is allowed. Feeding frequencies, escape reaction and school density were analysed. C. chromis specimens were also collected from 2007 to 2008 to evaluate their physiological state using the Body Condition Index as a proxy of feeding efficiency. The MPA was more exploited by nautical tourism during holidays than on weekdays, particularly in the middle of the day. Greater traffic volume corresponded with lower feeding frequencies. The escape reaction was longer in duration (>1 min) when boat passed nearby, while moored boats did not induce an escape response. We found no differences in density between schools in the A- and B-zones and worse body conditions among those individuals inhabiting the B-zone in one area only. Overall, our findings revealed a significant modification of the daily foraging habits of C. chromis due to boat noise, which was slightly buffered by no-take zones established within the MPA.

Acoustic cues to caller identity in lemurs: a case study

This study investigated the acoustic structure of grunt vocalizations in red-bellied lemurs (Eulemur rubriventer) and its potential for individual discrimination. Acoustic analyses were performed on 1,605 grunts recorded from seven lemurs belonging to two captive groups. From the perspective of sound-filter theory, we described the acoustic structure of grunts, measuring two sets of parameters: fundamental frequency characteristics as larynx-related variables and four formant frequencies as filter-related features. Formants were effective in assigning 80.5% of the vocalizations to the correct emitter against 24.9% scored by the model based on larynx-related variables. We concluded that vocal tract resonances might potentially provide conspecifics with individual cues.

Phylogeny of the salamandrid genus Triturus

Abstract The Salamandrid genus Triturus and its allies have attracted a considerable amount of interest for many years. As a consequence, much evidence has accumulated on a number of aspects on their karyology, allozymic variation, reproductive behaviour, taxonomy, osteology and even paleontology. Few of these studies, however, have made use of modern and more disciplined methods of phylo‐genetic reconstruction, and none have so far attempted to evaluate all the available evidence in a single analysis. This paper attempts to synthesize current knowledge into a comprehensive, multidimensional picture of the evolutionary relationships of Triturus, and to integrate it in a single phylogenetic tree. Mate recognition systems and environmental constraints were superimposed to the cla‐dogram and employed to generate a broader evolutionary scenario. All species of ≪bigger newts≫ (T. cristatus complex, T. vittatus) are characterized by a higly developed sexual dimorphism, based mainly on visual characters. In cont...

Chemical signals in European newt courtship

Abstract In European newt species there is good behavioural and anatomical evidence for the existence of chemical communication. Female odours can carry information to the male and influence the outcome of sexual encounters. There is good evidence that the abdominal gland, a male secondary sexual character, is the source of substances which act as ≪courtship pheromones≫. Preliminary studies suggest that these pheromones are a mucoproteic component of the gland secretion.

Ecogeographic analysis of morphological and life-history variation in the Italian treefrog

We describe the spatial pattern of variation in body size, body shape, and adult population age structure of the Italian treefrog (Hyla intermedia). By means of a non-parametric test of matrix association (the Partial Mantel Test), we investigate the role of climate and geography in explaining the patterns of phenotypic variation. Body size is the most important source of morphometric variation, both at intra- and inter-populational levels. Body shape, despite its secondary role in explaining variation, still maintains high discriminative power among populations. Age structure differs significantly among populations, since body size correlates positively to age, these differences partly explain geographic variation of body size. The patterns of variation in both age and body size are congruent with climate variation, suggesting causal relationship. However, we find no evidence for adaptive explanations and suggest that climate-induced demographically differential survivorship might be the proximate cause responsible for the associations observed. Unlike body size, body shape varies congruently with the pattern of between-population geographic distances, which we show to be highly correlated with their genetic distances, thus suggesting isolation by distance as the proximate cause of the association.

Morphological variation of the green-toad, Bufo viridis, in Italy: a test of causation

This study describes patterns of geographic variation in morphometric characters of the green toad, Bufo viridis, in the western part of its distribution, including the Italian Peninsula and the islands of Sardinia and Corsica. The causes of this variation were investigated by comparing observed patterns of interpopulational differences to hypothesized factors derived from climatic and geographic variables, through the use of canonical correlation analysis and partial Mantel tests. Among-population differences in morphometric characters include both size and shape. Island populations were found to have larger body sizes than mainland populations, and there was an association between climatic factors and morphological characters. Partial Mantel tests carried out on a number of possible causal hypotheses, both climatic and geographic, suggest that a large portion of this association should be interpreted as a spurious effect of genetic isolation between island and mainland populations and of the limiting effect of geographic distance in determining gene flow. urnal of Herpetology, Vol. 32, No. 4, pp. 540-550, 1998 pyright 1998 Society for the Study of Amphibians and Reptiles orphological Variat on f the Gr en Toad, Bufo viridis, in Italy: Geographic variation of genetically determined characters can be the result of both selection and restrictions to gene flow (Endler, 1982; Thorpe, 1987). Morphometric characters have been employed successfully in describing intraspecific geographic variation; it is assumed they are polygenically controlled and therefore can reflect the condition of a large number of loci (Atchley et al., 1982; Thorpe, 1983). Many studies on different vertebrate taxa have shown that the geographic pattern of morphometric variation can be explained either by natural selection for current ecological conditions, or by the influence of gene flow (Flischer and Johni i e etical y deterston, 1982; Malhotra and Thorpe, 1991; Malhotra, 1992; Castellano et al., 1994), i.e., either by ecogenetic factors (sensu Thorpe et al., 1991) or by historical factors (Thorpe, 1975, 1979). Historical caused geographic variation does not relate to current conditions but is explained by historical events, such as genetic drift occurring in small populations after isolation. Few studies on morphological geographic variation of vertebrate species have employed amphibians as a model (Calhoon and Jameson, 1970; Fishbeck and Underhill, 1971; Hedges, 1991; Mensi et al., 1992; Lee, 1993; Green et al., 1996). Nevo (1973) found clinal variation with 540 This content downloaded from 157.55.39.217 on Mon, 05 Sep 2016 04:00:32 UTC All use subject to http://about.jstor.org/terms GEOGRAPHIC VARIATION IN GREEN TOADS increasing body size from east to west in Acris crepitans and from north to south in Bufo viridis in Israel (Nevo, 1972). He interpreted these patterns as responses to increasing risks of desiccation, with selection favoring larger size in the more arid areas of both ranges. Lee (1993) found no significant association between body size and arid climatic conditions in Smilisca baudinii, but found a significant association between relative appendage length and total annual rainfall. Consistent with Allens ecogeographic rule, Lee (1993) suggested that desiccating environments can select for relatively short appendages. Lotter and Scott (1977) found a significant correlation between climatic parameters and morphology in Plethodon cinereus, while a number of studies on anurans have analysed variation in size in relation to altitude (Berven, 1982a, b) and latitude (Riha and Berven, 1991). Most of these studies considered body size variation but did not test a gene-flow hypothesis as the causal explanation of the observed patterns. Bufo viridis is distributed throughout the Mediterranean area (with the exception of southern France and the Iberian Peninsula), Central and Eastern Europe, Central Asia, and Saudi Arabia. This broad area of distribution is characterized by highly varied spatial structure and varied ecological conditions, from coastal environments to mountain (over 2000 m in altitude), and from deserts to riverine forests. In the Italian Peninsula the green toad is restricted to lowland habitats (from sea level to 600-700 m), whereas in Sardinia its range extends to include the highest mountains (1500 m above sea level). In this paper we describe the geographic pattern of morphometric variation in a part of the range of Bufo viridis, i.e., the Italian peninsula, Corsica, and Sardinia. A number of causal hypotheses were simultaneously compared to determine their relative significance in explaining observed patterns of variation. MATERIALS AND METHODS Samples and Morphometric Characters.-In April and May 1993 a sample of at least 10 adult males was collected from each of six breeding populations from throughout the Italian Peninsula, and from one population in Pellestrina, a small island in the Venetian lagoon, one population in Corsica, and two populations in Sardinia (Fig. 1). Some of these localities were also visited during the 1994 and 1995 breeding seasons, for a total sample of 184 males. Specimens were captured at their breeding sites during reproductive activity. Body mass and 20 body proportion characters (Fig. 2) were measured on anaesthetized specimens. Measurements were made to the nearest 0.01 mm w th dig tal calipers. All morphometric data were collected by the same researcher to avoid inter-observer source of variation (Lee, 1990). Description of the Pattern of Geographic Variat on.-To minimize deviations from normality and distortion effects caused by allometric relationships, all body measurements and body masses were log-transformed. Univariate and bivariate parametric statistics were calculated. To analyze separately size and shape factors, we first defined a multivariate size factor and then adjusted all body proportion characters with respect to the body size component. Multiple group principal component analysis (MGPCA; MULT program, Thorpe, Bangor Univ., UK) was used to obtain a multivariate expression of the size factor. As described by Thorpe (1983), when applied to morphometric data, MGPCA makes it possible to find a first component which is highly correlated among characters and best expresses body size. Therefore, the largest principal component obtained by MGPCA on the correlation matrix of log-transformed morphometric characters was assumed to represent the size factor. Residuals of regressions of the size-factor and the log-transformed characters were considered new values of size-adjusted body proportion characters and univariate analysis of variance were performed on these variables. Generalized patterns of geographic variation were obtained by applying Canonical Variate Analysis (CVA) to the correlation matrix of logtransformed data. To avoid problems due to colinearity effects, the minimum number of informative variables was determined by using MGPCA as an exploratory device, following the methods described by Reyment et al. (1984). Causal Analysis of Geographic Variation.-Each locality was defined by geographic coordinates and by a binary variable distinguishing Sardinia-Corsica populations from mainland populations (including Pellestrina). Altitude was not considered in the analysis, because eight localities are at sea level and two (Pellice and Isolabella) are only about 300 m above sea level. Four climatic parameters also were used to characterize each locality: (1) mean annual temperature (MAT); (2) total annual rainfall (AR); (3) aridity index (AI); and (4) prolonged activity index (PAI). All climatic variables were measured directly from climatic diagrams reported in Walter and Lieth (1967) of meteorological stations within 40 km from the study sites and at comparable altitude. The aridity index was obtained by measuring the total area comprised below the monthly average rainfall curve and above the monthly average temperature curve, during the water deficit period, as proposed by Gaussen (in Walter and Lieth, 1967). The prolonged activity index was defined as the portion 541 This content downloaded from 157.55.39.217 on Mon, 05 Sep 2016 04:00:32 UTC All use subject to http://about.jstor.org/terms S. CASTELLANO AND C. GIACOMA FIG. 1. Map of the Italian Peninsula, Sardinia, and Corsica showing localities from which specimens were collected. of the year with a mean daily temperature higher than 15 C. This value corresponds approximately to the mean air temperature of April in the northernmost localities sampled (Pellice, Isolabella), when most of the animals become active after winter latency. Canonical correlation analysis (CCA) on all body proportion characters of all specimens was used to obtain a general overview of the relationships between independent climatic variables and dependent morphometric characters. However, one intrinsic limit to CCA is its inability to include simultaneously the effects of geographic proximity. To overcome this limit, the partial Mantel test of matrix association (Smouse et al., 1986; Manly, 1991), a randomization test, was employed (Manlys RT-MANT program, modified by Thorpe). This analysis calculates the partial regression coefficients among a dependent distance matrix and up to eight independent distance matrices. Distance matrices were obtained by calculating betweenspecimens taxonomic distance (Sneath and Sokal, 1973). All distance matrices were standardized to obtain partial regression coefficients. Dependent morphological distance matrices were calculated by employing: (1) the first six CVA scores; (2) the body size factor scores; (3) 542 This content downloaded from 157.55.39.217 on Mon, 05 Sep 2016 04:00:32 UTC All use subject to http://about.jstor.org/terms GEOGRAPHIC VARIATION IN GREEN TOADS