The paper focuses on the long-term taxonomic composition and distribution of the shallow-water sponge fauna from the meromictic-anchialine coastal basin Faro Lake (Southern Italy), comparing recent qualitative field data with literature data over a 50-year period. The Faro Lake shallow water currently hosts 24 conspicuous species of Porifera belonging to 21 genera, 18 families, eight orders, three subclasses and two classes, i.e. Demospongiae (23) and Calcarea (one). The comparison between the present and past status of the sponge fauna showed a high turnover, with 15 new colonizers and only nine persistent species. Thirteen species reported in the literature are missing, suggesting the occurrence of remarkable changes in the faunal composition during the last 50 years. The analysis of the geographic distribution of each species allowed us to outline the prevalent North Atlantic affinity of the sponge community. Worthy of note is the new record of the alien calcareous sponge Paraleucilla magna of cryptogenic origin.
In this study, we aimed to characterise the genetic diversity of Italian pigeon breeds and describe the relationships among them and other European lineages, conjecturing which processes have led to actual breeds. We analysed the eight most diffused Italian pigeon breeds in addition to 11 foreign lineages that could have shared common ancestors or have been used in the creation of the Italian breeds. We analysed 12 autosomal microsatellite loci in 427 samples collected from 19 breeds belonging to six main groups of domestic pigeons (tumblers and highflyers, structure, owls, wattle, utility and hen). Genetic variability did not differ considerably among breeds, with an average observed heterozygosity (HO) of 0.550 ± 0.072 (max = 0.661 in breed Sottobanca; min = 0.411 in breed Frillback). The 21.34% of total genetic variation found was partitioned among breeds. Italian pigeon breeds were assigned coherently to their respective groups of origin. The analysis supports the origin of homing pigeons from English Carrier and the existence of a close relationship between Old Dutch Capuchine and Italian Owl. Despite the differences in body size, pigeons of the breeds belonging to the hen group are genetically very similar. The sub-populations recognised by breeders inside Italian Owl and Triganino are not genetically supported and their identification as new breeds ought not to be yet proposed, although they are morphologically distinguishable. Consequently, it could also be discussed how the genetic characterisation of domestic lineages could give useful information in breeding and selection processes.
The Mediterranean fruit fly, Ceratitis capitata (Wiedemann, 1824) (Diptera: Tephritidae), is a polyphagous pest in horticulture, mainly targeting pomaceous and citrus fruits. To gain better knowledge about its chemosensory system related to taste, essential for behavioural strategies and localisation of host plants, we examined the tarsal external morphology by high-resolution scanning electron microscopy, focusing on sensilla. Numerous trichoid and chaetica sensilla, related to taste and mechanoreceptor systems, and other types of sensilla are present in tarsal segments. The responses of specific trichoid chemosensilla were also studied through electrophysiological experiments by stimulation with sodium chloride, fructose and four bitter stimuli. Electrophysiological data allowed us to distinguish three types of different neurons: high ("H"), middle ("M") and small ("S"). Increasing concentrations of sodium chloride enhanced the activity of H cells, while fructose boosted M cells activity. On the contrary, S cells showed no increase in spike activity after stimulation with these substances. Bitter stimuli induced no significant response on these cells. Behavioural assays showed no statistical difference among the responses to sugars, bitter substances and citric acid. Our results on taste stimuli will be useful in increasing knowledge of Ceratitis chemoreception, fundamental in new integrated pest management.
Morphological analysis of recently collected specimens of the slender finless eel Apterichtus anguiformis (26 specimens) and the European finless eel Apterichtus caecus (14 specimens) in waters off the coast of Sardinia (central-western Mediterranean) confirmed their distinction from each other. Analysis also revealed a pronounced difference in mouth length in A. anguiformis from Sardinian waters when compared to the holotype and published data.To clarify their taxonomic status, morphological characteristics of the finless eels were analysed using morphometric and meristic characters. The morphometric differences between species were mainly related to the position of the anus and to cranial-related characters. Variation in meristic traits revealed differences in the number of operculum and pre-anal pores as well as the number of total vertebrae. Finally, we were able to capture specimens of these rare species using experimental trawl fishing gear, in which the entire cod-end was covered with a fine mesh net size of 8 mm; this sampling approach would be a good sampling method for further studies.
Calathus cinctus Motschulsky, 1850 was only recently separated from the group Calathus melanocephalus (Linnaeus, 1758). C. cinctus has now been recorded for the first time in Croatia, along the temporary Krcic River situated beneath Mt. Dinara. However, revision of museum collections revealed that this species also occurs at other localities in Croatia, in the Alpine region and along the Adriatic coast. Its sister species C. melanocephalus, as the type species of the group, is widely distributed in Croatia, whereas C. mollis Marsham, 1802 is mostly restricted to the coastal region, with a few records from Alpine and Continental Croatia. The distribution range of C. cinctus overlaps with the distribution ranges of its sister species. Life-history traits were studied using pitfall traps in a karst region of Croatia, including eu-Mediterranean and sub-Mediterranean zones, in riparian and karst habitats, and on agricultural land. Based on goodness-of-fit criteria, the zero-inflated negative binomial model and negative binomial model best described the distribution of C. cinctus. For both models, there was a statistically significant difference between habitat types for activity density, indicating that C. cinctus has a preference for open habitats. It was recorded above a range of soil types (e.g. red, brown, sandy, cultivated), with sparse vegetation, suggesting that sufficient sun exposure is a more important requirement than soil type. The seasonal dynamics of C. cinctus differed between eu-Mediterranean and sub-Mediterranean zones, despite the rather close proximity of the studied localities. Geographical variability of seasonal activity was most likely due to differences in climate, altitude and the vicinity of the high mountain. Calathus cinctus populations in both zones were wing-dimorphic, with brachypterous specimens prevailing in both populations, indicating population stability.
Different hypotheses exist to explain the ability of individuals or species to modify their behaviours in response to the urban environment. Our study addresses risk-taking in urban birds as an essential behavioural change in cities allowing the species to manage living in anthropic habitats. Specifically, we tested role of phylogeny and the environment on risk-taking, expressed in lower escape distances. We adopted a comparative approach and compared the flight distance of urban pigeons and urban crows in Paris with rural wild rock doves and crows in Sardinia, thus contrasting environmental conditions (urban or rural), species (columbids vs. corvids) and type (feral or wild). Pigeons had lower flight distance than crows in both rural and urban environments, and rural individuals of both species had higher flight distance than urban individuals. However, this intraspecific difference was higher in pigeons than in crows, and the interspecific difference was higher in urban than in rural areas. Our study shows that risk-taking in birds is the outcome of a complex interplay between several environmental and phylogenetic factors, and confirms the hypothesis of increased risk-taking in urban pigeons as a result of a pre-adaptation due to artificial selection, as often suggested but never scientifically demonstrated.
The dogfish Scyliorhinus canicula (Linnaeus, 1758) is a primitive cartilaginous fish, evolutionary placed among cephalochordates (Cephalochordata) and teleost fish (Osteichthyes). In this study we present the ultrastructural features of the dogfish notochordal cells and the notochordal sheath, revealed by light and electron microscopy. The dogfish notochord continuously passes through notochordal canal inside the vertebral centrum. It expands in the area of the intervertebral disc placed in between two adjacent vertebrae. Two notochordal cell types could be distinguished: marginal and central ones. Due to a significant intracellular and intercellular vacuolization central notochordal cells are thin and elongated, forming a net-like structure inside the notochord. The desmosomes are the usual type of junction between notochordal cells. The notochordal sheath of dogfish vertebra is an acellular structure composed of an elastic membrane surrounded by bundles of collagen fibres arranged in different orientations and directions. The ultrastructure of the dogfish notochord revealed a similar structure to those of other vertebrates including humans.
Zoology is disappearing from university curricula in first-world countries (whatever this means). New generations of biologists are illiterate in biodiversity, due to a mismatch between their initial expectations and what is proposed to them as “modern biology”. Almost invariably, young specimens of our species are attracted by living beings, especially animals. This tendency is reinforced by a myriad of TV programs about nature. Biology is synonymous with natural history, implying the exploration of secluded places, while looking for still unknown creatures. This is what pushed me towards biology; I made my thesis in a tuna trap, with a crew of rough fishermen, then spent long periods in places ranging from Papua New Guinea to California, and found many previously unknown species (and genera, and families), diving in shark-infested waters, exploring marine caves and following the seasons of the sea along vertical rocky cliffs from the surface to 30 m depth. Now, regular biology students spend their lives in the laboratory and see the world through the graphs of sophisticated machines. If they encounter animals, they do not know what they are by just looking at them, and the only chance they have to give them a name is to grind them, extract some sequences and match them with online databases. E. coli and C. elegans are more or less the same thing, together with Arabidopsis and D. melanogaster, a distant relative of the zebrafish! In some Italian universities, however, zoology is still taught, even if the hours dedicated to it are decreasing year after year. Francesca Strano, one of our students at the University of Salento, made her master thesis on a new species of pterobranch that we found some time ago in a marine cave. I had never seen a pterobranch before, and that was the first time a member of this class had been found in Italian waters, the second finding in the Mediterranean Sea. Francesca followed the life cycle of this beast, and studied the architecture of its nervous system, but the most important result was that she had stumbled into a species unknown to science, right in our backyard! Valerio Micaroni works at his master thesis in our new marine laboratory, the Mare Outpost at Tricase Porto. I gave him a very difficult task: produce an all-species inventory of the local fauna. He is in the water every day, and brings stuff to the lab, where he tries to give names to specimens, and to elucidate their life cycles, just as Francesca did with her pterobranch. Not easy at all, since most of the knowledge is frozen in outdated monographs, and knowledgeable living beings are rapidly disappearing. Francesca and Valerio are having great fun and spend all their time in studying their beasts; there is nothing else they want to do. The fishermen and the children of the village admire their passion and help them in their studies. The ocean literacy of the people of Tricase Porto is increasing and they come to the Outpost with their observations, asking questions. Culture evolved from our ability to observe animals, as witnessed by cave paintings, and we have an instinctive curiosity towards them. The education system is trying hard to eradicate this tendency from us, and the result is the lack of respect for nature that characterizes our relationship with the rest of the world. Zoology is the primeval form of culture, it’s the root of our history, and we are severing it from the rest of our cultural heritage. Francesca and Valerio are like Adam and Eve, in the forgotten Eden that we have in front of us (in which animals are still unnamed) but that we cannot see anymore. No wonder that children are their best assistants, as they are still uncorrupted by an education system that implacably separates our species from the rest of Nature, as if we could survive without her. If zoology is expelled from the capacity building system, as it is, and nobody teaches how to give names to animals anymore, we will rapidly lose our sense of responsibility for the ecosystems that sustain us. The modern trends in biology are leading to Italian Journal of Zoology, 2016, 283–284 Vol. 83, No. 3, http://dx.doi.org/10.1080/11250003.2016.1223610
This work provides the first morphological analysis (both at gross and fine level) of the antennal structures in the genus Elater (Coleoptera, Elateridae). The typology, number and distribution patterns of the antennal sensilla in the rare saproxylic Elater ferrugineus (both male and female) were studied using scanning electron microscopy (SEM). The serrate antennae of E. ferrugineus consisted of a scape, a pedicel, and nine flattened flagellomeres. Overall, 10 types of sensilla were identified according to their morphological features: one type of sensilla chaetica (Ch), one type of Bohm sensilla (Bo), three types of sensilla trichodea (Tr.1-3), two types of sensilla basiconica (Ba.1-2), one type of sensilla styloconica (St), one type of grooved peg sensilla (Gp) and one type of sensilla campaniformia (Ca). A marked sexual dimorphism was found at both gross and fine scale. The male antenna was bigger (8.6mm) than the female one (7.0mm) and carried one type of sensilla trichodea (Tr.2) absent in female antennae possibly responsible for reception of the female-emitted sex pheromone. The female antenna carried a higher number of sensilla ( 9800) than the male one did (7,000), with more abundant sensilla chaetica (Ch) and basiconica (Ba.1 and Ba.2).
Hearing sensitivity affects survival and reproduction in animals that communicate vocally. The Chinese tiger frog exhibits sexual dimorphism in body size, reflecting the evolution of mating behaviour and life-history strategies. In this study, we recorded auditory brainstem responses (ABRs) to determine hearing sensitivity in both female and male frogs. We also compared male and female hearing characteristics with the shape of the tympanic membrane in light of previous studies showing that smaller middle ear cavities improve hearing sensitivity. We found that ABR thresholds differ significantly between males and females, with the greatest sensitivities in both sexes at frequencies close to the dominant frequency of male calls. ABR thresholds were significantly lower in females compared to males for frequencies in the 0.9-1.3 kHz range and at 1.6 kHz. The tympanic membrane diameter was significantly smaller in females (5.94 +/- 0.87 mm) than in males (6.71 +/- 0.49 mm). Our results indicate that sexual selection has in all likelihood differentially affected male and female hearing sensitivity as well as the shape of the tympanic membrane in frogs.
The egg white and egg yolk are the two main sources of nutrients for the developing avian embryo. Egg white ultimately reaches egg yolk before being consumed by the embryo. Previously, in the turkey Meleagris gallopavo, we showed that the major egg white transfer into the yolk through the amnion and intestinal lumen of the embryo started on day 17 and became obvious on day 19. We also suggested that the transferred egg white and endogenous yolk proteins undergo digestion at late developmental stages. However, the protease activity throughout development and the type of activated proteases are completely unexplored in the yolk of turkey eggs. Here, we measured the general proteolytic activity in the egg yolk during different developmental stages using casein as a substrate. Furthermore, we determined the type of activated proteases by employing different types of protease inhibitors. Protease activity in the egg yolk was basal throughout development until day 19 when activity significantly increased, remaining high thereafter. Moreover, acidic aspartic protease(s) were primarily activated in the yolk. Our results suggest that the transferred egg white and endogenous yolk proteins are mostly degraded by the aspartic proteases that become highly activated late in development.
All of the published studies but one about the diet of the Eurasian scops owl Otus scops, a nocturnal raptor of conservation concern, were carried out during the breeding period, just before or immediately after the chicks fledged. The species is a trans-Saharian migrant with few resident populations in Europe. Orthoptera make up the staple of its diet in summer. In this study, we investigated the diet of scops owls on the island of Pianosa after the breeding period through the analysis of pellets. A total of 327 fragments belonging to at least 14 taxa were identified from 56 pellets collected after the breeding period, between late August and March. By frequency, invertebrates constituted 80.00% of the diet, with Coleoptera being the most represented order (62.35% of the total diet) and Orthoptera poorly represented (8.24%). Vertebrates included two bird species, three small mammals and the Moorish gecko. Although the meal-to-pellet interval for scops owls is unknown, we suggest that the bank vole, which is not recorded on any Italian island, and possibly the wild mice, may have been preyed upon in nearby areas, before a migratory movement towards a warm area (e.g. Pianosa) occurred.
Eremias strauchi strauchi and Eremias strauchi kopetdaghica are genetically and morphologically distinct and are distributed allopatrically in northeastern and northwestern Iran. E. s. strauchi is distinguishable by having green spots on lateral parts of the body, while E. s. kopetdaghica is characterized by white spots and irregular black dots on lateral parts of the body. Recent molecular studies have suggested that these are two distinct species, but other types of analyses leave their classification unclear. In this study, we evaluated their taxonomic status using additional data (including ecological niches) to confirm the hypothesis that they are two species. All known records of their occurrence were employed to predict and evaluate the suitable areas where they may be expected to be found in Iran. We then performed niche similarity tests (niche identity and background tests) and point-based analyses to compare their ecological niches and explain ecological differentiation. Niche models of E. s. strauchi and E. s. kopetdaghica had good results and powerful performance based on high area under the curve (AUC) values [E. s. strauchi=0.992, standard deviation (SD)=+/- 0.008; E. s. kopetdaghica=0.978, SD=+/- 0.032]. Ecological differentiation has been found across the entire range, indicating that ecological differentiation had an important role in species differentiation. Environmental conditions for the species diverged along environmental variables, as precipitation of coldest quarter for the Strauch subspecies and precipitation of warmest quarter for the Kopet dagh subspecies were most important in determining habitat suitability, respectively. These two factors are important in niche differentiation between the two species and influenced their genetic divergence. Finally, our results confirmed the niche differentiation between E. s. strauchi and E. s. kopetdaghica and added new insights into the taxonomic distinction between E. s. strauchi and E. s. kopetdaghica.
Development of different embryonic stem cells (ESCs) requires feeder fibroblast cell culture. Moreover, the establishment of fibroblast cell culture especially for endangered species can provide an excellent resource for biological research and preserve precious genetic materials. This study aimed to characterize and determine the growth kinetic of hamster embryonic fibroblast cells. Hamster fetuses of two albino female hamsters were collected between 8 and 10days of pregnancy. After removal of the head, liver and gut, the fetuses were cut into 1-mm(2) pieces and then cultured. After reaching 80-90% confluence, the cells were subcultured. The cells of passage 8 were subcultured in two 24-well plates (2x10(4)cells/well) for 7days. Three wells per day were counted and the average cell counts at each time point were plotted against time, and the population doubling time (PDT) was determined. Cell viability after freezing and thawing was evaluated. For karyotyping, the cells of the passage 8 were used. The PDT of the cells at passage 8 was about 34.9h and the viability was 77.9% in the passage 8. The isolated cells were spindle shaped and plastic adherent. The chromosome number and morphology were normal. The favorable morphology, viability, growth kinetic and karyotyping of hamster embryonic fibroblast cells revealed that these cells even at the eighth passage can safely be used as a feeder layer for ESCs, transgenic purposes and gene banks, and also for biological and pharmacological research.
Holoplanktonic polychaetes constitute an exception within this taxon, which as adults colonize all the whole variety of brackish water and marine habitats. Nevertheless, they form a distinctive group in marine zooplankton and play an important role in the pelagic trophic nets. Pelagic worms are little studied, especially in the Mediterranean Sea, while information regarding the distribution of the families Typhloscolecidae and Iospilidae along Italian coasts is a century out of date. This paper deals with the state of knowledge of these polychaetes; it summarizes the previous records, updating them with the new records here reported from Tyrrhenian Sea, in order to check whether they have a bearing on Italian fauna. The findings reported in this paper confirm the presence of the Typhloscolecidae, with the species Sagitella kowalewskyi and Typhloscolex muelleri, and of the Iospilidae, with the species Phalacrophorus pictus and Iospilus phalacroides, along the Italian coasts, validating, in each case, their current presence in the Italian fauna. The main morphological features of these species and a dichotomous key for their identification are also reported.
Crossing water bodies (like lakes or rivers) by European roe deer Capreolus capreolus Linnaeus, 1758 is a known phenomenon. However, there is scarce information about the reasons for and patterns of this activity. We analysed 4-year localization data of 13 Global Positioning System-Global System for Mobile Communications (GPS-GSM) collared roe deer living in the floodplain forests of the river Tisza in the Hungarian Great Plain in order to describe such behaviour. Initially, we assumed that this river may represent a barrier for roe deer and we studied the frequency of river crossing occasions, between and within the studied animals. Our questions were: (1) Does the Tisza River act as a barrier to the movements of roe deer? (2) Are there any seasonal or daily variations in the crossing patterns? (3) Is there any difference between males and females regarding the water crossing patterns? (4) Does the water level or the increase in human presence (disturbance by hunting) have any impact on crossings? According to our data, 10 of the 13 individuals crossed the river at least twice, and eight of them did so several times or regularly. The periods spent on the different sides of the river varied from a few hours to several months. During the study period, animals of both sexes crossed the river without difference. There were crossings in all seasons, in daytime and nighttime also. We could not find any difference between the seasons, but there were more crossings in the daytime when we excluded the data of an outlier animal. Water level or human disturbance (live brown hare capture) had no impact on crossings. We conclude that the Tisza River does not represent a real barrier to the movements of roe deer, and our assumption was not supported.
The European Union, in its calls for projects (an abundant source of funds for the European scientific community), increasingly calls for holistic, integrative, cross-cutting, and ecosystem-based approaches. The scientific community tends to remain reductionistic, also due to overspecialization of journals, or to the compartmentalization of approaches even within the same journal. This leads to a mismatch between what society asks and what science offers. Indeed, science has profited much from reductionism. Complex problems are split into sets of simpler problems that are solved one at a time, then the solutions are assembled and the complex problem is solved. There is a problem, though: it does not work! The whole is more than the sum of the parts. The old philosophers knew it well: analysis must be followed by synthesis! The analytical efficacy of reductionism has led to great scientific advance and it would be unfair to label it as sterile. It is simply not enough. We need also to look at problems from wider perspectives, and connect all their facets into a common, synthetic landscape. Pushed into a corner by rampant reductionism, zoology tried to keep up with the trend and became fragmented into a host of subdisciplines that became increasingly separated from each other. This is witnessed also by the vast array of topics in this journal: surely most readers have little interest in all of the articles of each issue, since the barriers among subdisciplines (from molecular biology to ecology and evolution) are becoming increasingly higher. Not to mention the barriers that divide zoology from the other branches of biology. Science is exposed to a Tower of Babel risk. The scientists who are building the Tower of Knowledge have developed different languages and cannot communicate with each other. Furthermore, they fail to communicate with the rest of society that, indeed, is asking for a change. For instance: we cannot resolve health problems created by bad environmental conditions by curing the proximate causes (the illnesses) with hospitals; the ultimate causes must be removed, bringing the environment back to a healthy state, leading to healthy humans. Medicine is a reductionistic approach to human health, ecology is a holistic approach to the same problem: you cannot have healthy humans if the environment is unhealthy. As simple as that! But, apparently, we are not ready to understand it. Of course this is not a problem that can be solved within a journal. We will continue to publish articles that range from ecology to molecular biology, focusing on animals (and protozoans). However, it might be the case to encourage some progress towards unitary visions. We have the “grand picture”, by the way: it is evolution or, better, ecology and evolution: the change of the individuals (and of their parts) as a response to environmental pressures. In the past, this was called “natural history”, and Darwin (who was eminently a zoologist) labelled himself a naturalist. Today, in addition to zoology, he would have also practiced molecular biology, to solve his “little problems”. After a century of splitting things for ease of analysis, now we need to produce a synthesis, but we lack the conceptual tools to do it, being overwhelmed by the details. Meanwhile, the decision makers ask for widerscoped approaches. The communication between us and them is impaired. Those who promise magic solutions to all problems are the most heard and, if consulted, we usually produce cumbersome essays on our pet topics that, if confronted with the problems of the world, seem almost irrelevant. On one hand, we claim that the world is in peril, while on the other hand we produce...the genome of the banana. I have absolutely nothing against genomics, but the wonderful promises of genomic approaches are crashing against the need of further splitting: now we have proteomics, and metabolomics, and then epigenetics. If a new machine is invented that allows us to perform an operation, we all want it to play with it, and we do things because we have a machine that allows us to do them. It is important, but it is not enough. And all these fragments must be assembled in a way that allows us to see the forest and the trees, and not only the leaves of the trees. Italian Journal of Zoology, 2016, 151–152 Vol. 83, No. 2, http://dx.doi.org/10.1080/11250003.2016.1189647
Resource partitioning may allow species coexistence. Sand dunes in the typical steppe of Inner Mongolia, China, consist of desert, shrub and grass habitats, providing an appropriate system for studies of spatial niche partitioning among small mammals. We collected data to verify the niche separation hypothesis that coexisting small mammals would separate into spatial niches, and the productivity hypothesis that the highest species richness and overlap were to be expected in the most productive and diverse shrub habitat of the north-facing slopes, in contrast with the less productive grass and desert habitats of sand dunes. We trapped small mammals on 44 sand dunes in the summer of 1984 using snap traps. We captured 12 species of small mammals among three types of habitats. Cricetulus barabensis was a habitat generalist, present in all three types of habitats. Spermophilus dauricus was present only in the grass habitat, Allactaga sibirica and Dipus sagitta only in the desert habitat, and Apodemus peninsulae primarily in the shrub habitat. The shrub habitat hosted the largest number of small mammal species among the three types of habitats, supporting the productivity hypothesis. Habitat separation is an important mechanism for structuring small mammal communities in Inner Mongolia grasslands.
Tree sparrows exhibit a range of breeding tactics from nesting in solitary pairs to forming breeding aggregations. We present a case study on the reproductive consequences of nest positioning in a loose breeding colony of Eurasian tree sparrow (Passer montanus) in central Turkey. We tested whether height and centrality of nests, together with their interaction, influenced fledging success in a single breeding season by running a generalized linear mixed-effects model. Nest height did not influence fledging success in a significant way. Also, productivity did not differ relative to the distance from the colony edge. This study provides the first detailed information about the effects of nest location on productivity for tree sparrows outside Continental Europe, and emphasizes the need for further studies on this model species.
The American bullfrog, native to the eastern half of North America including southern Quebec, is considered one of the most invasive species in the world. It has been introduced in America, Asia and Europe, mainly for food purposes. A study on the age and body size of this species was carried out on individuals obtained from four introduced populations (one from Western Canada and three from France), using the skeletochronological method. Adults did not differ between sexes in mean body size or mean age, with the exception of one population in France where males were younger than females. Several differences in the mean age and body size were observed, with the individuals from the population in Canada exhibiting the highest values for both sexes. The scarcity of studies in the native range prevents the comparison of introduced versus native populations, and we focus on comparisons between introduced populations.
