Population aspects of sexual dimorphism in Mustelidae from the example of four species (Mustela lutreola, Neovison vison, Mustela putorius, and Martes martes)

Size sexual dimorphism was studied on 695 crania of four species of the Mustelidae. According to the degree of increasing differences between sexes, the species were arranged in the following order: common marten (Martes martes), European mink (Mustela lutreola), American mink (Neovison vison), and black polecat (Mustela putorius). The value of dimorphism characterizes the ecological flexibility of species and is an integrated population characteristic. It was demonstrated that M. martes occupies a specific and relatively narrow ecological niche of the forest ecosystem and joins weak competitive relations with smaller species of Mustelidae. The level of sexual dimorphism in M. lutreola and N. vison, as well as M. putorius, reflects the tension of their interspecific relationships in a given territory. A high level of sexual dimorphism in M. putorius is caused by further divergence of the ecological niches of males and females, being a compensatory mechanism, which mitigates the consequences of toughened environmental requirements.     

Home ranges of European mink<Emphasis Type="Italic">Mustela lutreola</Emphasis> in southwestern Europe

We radiotracked 7 European minkMustela lutreola Linnaeus, 1761 (5 males and 2 females), to determine their distribution, size and temporal changes of their home range in an area of southwestern Europe, where American minkM. vison was not established. Size of home ranges varied from 11 to 17 km along watercourses in males and were 0.6 and 3.6 km in females. Home ranges of males were larger than those found in previous studies. Most females captured (either radiotracked or not) were found within the home range of males. Males occupied adjoining river sections with minimal range overlap, suggesting an intrasexually exclusive spacing pattern for males. Each month males used new river stretches, mainly along tributaries; meanwhile they showed a steady use of their stem river section. Resting sites were mainly beneath dense brambles ofRubus patches located in the river bank.     

Microsatellite markers for the endangered European mink (Mustela lutreola) and closely related mustelids

The European mink (Mustela lutreola L., 1761) is an endangered carnivore species whose populations suffered a severe decline during the last century. The genotyping of eight polymorphic microsatellite loci revealed a relatively low number of alleles per locus (two to eight), as well as low levels of polymorphism (observed and expected heterozygosity values per locus were 0.49 and 0.54, respectively). Cross‐specific polymerase chain reaction amplifications were successful in seven closely related mustelid species suggesting that these loci may be useful not only for assessing genetic variability in European mink populations but also for determining potential hybridization events between M. lutreola and other mustelid species.     

Role of fruits in the diet of small mustelids (<Emphasis Type="Italic">Mustela</Emphasis> sp.) from the western Italian Alps

The food habits of both weasels and stoats (Mustela nivalis and M. erminea) and the occurrence of fruit in their diet were studied by scat analysis in the Gran Paradiso National Park (western Italian Alps). Being impossible to distinguish between stoats and weasels scats, they were grouped together as the genus Mustela. Despite the high consumption of small rodents, which represented the main food item in the diet of small mustelids (41.5% in mean volume), wild fruits (mainly Rosaceae and Ericaceae) were also relatively common (23.3% in mean volume). Fruits were exploited throughout the year, with an intensive use in seasons of high availability. Their consumption did not significantly differ between habitat types, despite a significant decrease of fruit availability from deciduous mixed forest to alpine prairie. This evidence suggests that this trophic behaviour could represent a consolidated feeding strategy of both weasels and stoats, which seem to adopt an opportunistic behaviour as shown by larger size mustelids. We argue that fruits, owing to their good availability and high profitability, could play an important role in the diet of small mustelids in alpine habitats, slackening their well-documented dependence on rodents.     

Population genetic structure and distribution of introduced American mink (<Emphasis Type="Italic">Mustela vison</Emphasis>) in Spain,based on microsatellite variation

The population genetic structure of an invasive species in Spain, the American mink (Mustela vison), was investigated using microsatellite DNA markers. This semi-aquatic carnivore, originating from North America, was imported into Europe for fur farming since the beginning of the 20th century. Due to massive escapes, farm damages, deliberate releases and/or accidents, feral mink populations were established in the aquatic ecosystems of many European countries, including Spain. We genotyped 155 American mink originating from the Spanish regions Basque Country, Catalonia, Castilla-Leon, Aragon, Valencia and Galicia using 10 polymorphic microsatellite loci to highlight population genetic structure, distribution and dispersal. M. vison populations in Spain appear differentiated and not yet connected by gene flow. Bayesian clustering analyses and spatial analyses of molecular variance detected four inferred clusters, overall coinciding with the sampled geographical localities. Preliminary testing shows moderate to large estimated effective population sizes. Molecular analyses result useful to provide baseline data for further research on the evolution of invasive mink populations, as well as support local management strategies and indirectly benefit the conservation of threatened species in Spain, such as the endangered European mink (Mustela lutreola), and the polecat (Mustela putorius), which share the habitat with the American mink. This paper is dedicated to the memory of Xavier Domingo-Roura.     

Mink (Mammalia; Carnivora; Mustelidae): correction of a widely quoted error

Since the European Mink Mustela lutreola and the introduced American Mink M. vison are now sympatric in some parts of the former's native range, and since the two species are similar in appearance, ecology, and behaviour, a need has arisen for a simple way of discriminating live specimens of the two species in the field. Many publications, particularly field guides, have recommended diagnosis on the basis of the presence of white hair on the upper lip of the European species, and its absence in the American species. This is a mistaken suggestion, which should be avoided by authors. American Mink seldom if ever show the large white moustachial bands seen in some European Mink, and may indeed have no white hairs on the upper lip; but white patches of lesser size are common enough to be a possible cause of confusion.     

Comparative substrate-inhibitor analysis of mink liver monoamine oxidases

Comparative substrate-inhibitor analysis of catalytic properties of liver monoamine oxidases (MAO) was performed in the mature males of the American mink Mustela vison and the European mink Mustela lutreola. The action on the MAO activity was studied of alkaloids of the benzo[c]phenanthridine group: sanguinarine and chelidonine, diisoquinoline alkaloid berberine, medicinal agents “Ukrain” and “Sanguirythrin” as well as derivatives of 2-propylamine: deprenyl and chlorgylin. The latter turned out to be irreversible inhibitor of the MAO A form, whereas deprenyl-irreversible inhibitor of the MAO B form in both studied mink species. The selectivity of action of each inhibitor on the corresponding liver MAO form for the species M. vison was one order of magnitude stronger than for the species M. lutreola. All studied alkaloids as well medicinal agents on their basis have been shown to be specific irreversible inhibitors of the intermediate strength of the liver MAO A form of both mink species. They inhibit the enzymatic deamination of serotonin, tyramine, and tryptamine without affecting the deamination reaction of benzylamine and β-phenylethylamine (at concentrations of 10 mM and lower). Out of five studied isoquinoline agents, the medication “Ukrain” and alkaloid chelidonine have the highest inhibitory action; the agent “Sanguirythrin” and alkaloids berberine and sanguinarine produce the weaker monoamine oxidase effect. The revealed specificity of action of the studied inhibitors is an indirect evidence for the presence in the liver enzymes of both mink species, like in the rat liver enzyme, of several molecular forms.     

Swimmers,Diggers, Climbers and More,a Study of Integration Across the Mustelids’ Locomotor Apparatus (Carnivora: Mustelidae)

Phenotypic integration, defined as the coordinated co-variation of parts of an organism can be an important constraint on phenotypic diversification. Functional factors, by having an heterogeneous impact across the animal body, may reinforce the integration of some parts while causing a perturbation of the integration among other parts. The integration across the locomotor apparatus should thus reflect to a certain extent the locomotor ecology of the animal. Using the mustelids as study group, we track changes in the patterns of co-variation in species belonging to four different locomotor ecologies (terrestrial, semi-arboreal, semi-fossorial, and semi-aquatic). Our results highlight the strong overall integration in mustelid long bones. The main shape changes associated with co-variations between skeletal elements are the bone robustness and proportions of the epiphyses. The pattern of co-variation is, however, only slightly impacted by allometry. Changes in co-variation between species mostly scale with phylogenetic divergence time, except for the (Mustela putorius, M. eversmanni, M. lutreola) clade which, despite a short divergence time, presents strong differences in co-variation. Co-variation patterns differ between locomotor ecologies, but few of these variations match the hypothesis of a reduction of integration due to functional specialization. This may reflect our lack of knowledge on the functional modules in species with locomotor ecologies that differ from terrestrial locomotion rather than invalidate our a priori hypotheses.     

Habitat utilization by sympatric European mink<Emphasis Type="Italic">Mustela lutreola</Emphasis> and polecats<Emphasis Type="Italic">Mustela putorius</Emphasis> in south-western France

The European minkMustela lutreola Linnaeus, 1761 and the European polecatMustela putorius Linnaeus, 1758 are related species sympatric in southwestern France. The European mink is rapidly disappearing whereas the polecat maintains good populations. Seasonal habitat use of both species was compared in the Landes de Gascogne region to identify if some vulnerability factors of the European mink were associated with habitats occupied by this mustelid. Potential habitats were mapped using a satellite picture and 12 main types of habitats were defined. Animal locations were recorded by radiotracking 9 European mink and 14 polecats from March 1996 to August 1999. Resting animals were located by triangulation, and, when possible, resting places were described. Animals in activity were tracked by continuous monitoring. Data collected revealed a strong preference of European mink for flooded habitats, particularly open marshes, flooded woodlands and moorlands. They seldom left the corridor of the riparian forest and their resting places were mainly in flooded environments, above ground (under herbs or bushes) or in cavities between tree roots. European polecats were less tightly linked to wetlands. Most of their locations were in the pine forests outside the valleys and their resting places were mainly in burrows. The strong specialisation of European mink in aquatic habitats is probably one of the main reasons for its decline because wetlands suffer drastic damages throughout all of its range. Maintaining adequate water levels is crucial for satisfying habitat requirements of mink.     

Endozoochorous seed dispersal by sympatric mustelids, Martes melampus and Mustela itatsi, in western Tokyo, central Japan

We investigated seed dispersal by two sympatric mustelid species, the Japanese marten (Martes melampus) and Japanese weasel (Mustela itatsi), along an intercity forest path in western Tokyo, central Japan, from Jul 2007 to Jul 2008. We aimed to investigate the effect of food/habitat preference of these mustelids (martens are semi-arboreal frugivores while weasels are terrestrial carnivores) on their seed dispersal characteristics, which determine their efficacy as seed dispersers. In total, we analyzed 478 fecal samples collected from the two mustelids (N_marten = 381, N_weasel = 97). The proportions of feces containing seeds for martens and weasels were 81.4% and 55.7%, respectively. The number of plant species whose seeds were found within the feces were 28 and 17, respectively. Almost all seeds within feces of both mustelids were intact. The number of plant species whose seeds were found within a single fecal sample ranged from one to four, but no significant difference was detected between the two mustelids. However, marten feces contained a significantly greater number of seeds of most plant species as well as total number of seeds than did weasel feces. The numbers of plant species and seeds represented in marten feces varied seasonally, but those represented in weasel feces did not. Our findings suggest the possibility that both mustelids act in some ways as seed dispersers, although martens seem to disperse a greater diversity and total amount of seeds.     

Biogeography, geographical variation and taxonomy of the Andean hummingbird genusMetallura GOULD, 1847

Summary Biogeography and taxonomy of the High-Andean hummingbird genusMetallura were analysed on the basis of geographical variation of morphometric and plumage colour characters. The genusMetallura is considered to consist of nine species and 15 subspecies. Within the speciesMetallura tyrianthina seven subspecies are recognized (smaragdinicollis [includingperuviana],septentrionalis, quitensis, tyrianthina, districta, oreopola, chloropogon).M. tyrianthina andM. iracunda are considered to be sister species and to be closely related toM. phoebe and to the members of theM. aeneocauda superspecies. The latter consists of six species as follows:M. aeneocauda (with subspeciesaeneocauda andmalagae),M. eupogon, M. theresiae (with subspeciestheresiae andparkeri),M. odomae, M. baroni andM. williami (with subspecieswilliami, atrigularis, primolina, recisa).M. tyrianthina andM. iracunda exhibit plesiomorphic character states (dimorphism, colour of throat feathers, short bill), that link the genusMetallura to its sister genusChalcostigma. The disjunct distribution of similar phenotypes, and the progression of morphological characters suggest fairly recent allopatric speciation processes in allMetallura taxa. High-Andean habitat fragmentations due to climatic changes during Late-Pliocene and Pleistocene presumably caused geographical isolation and differentiation of mostMetallura populations. The south-north phenotype progression regarding chin and gorget coloration ofM. tyrianthina females, paralleled by a transition from weak to strong sexual dimorphism, suggest for the genusMetallura a centre of origin in the Andes of north-eastern Bolivia or south-eastern Peru.Dedicated to Hans Hudde, Essen, for his friendship and support.     

Isoenzyme spectra of lactate dehydrogenase in tissues of mammals of the Mustelidae family

A comparative analysis of distribution of lactate dehydrogenase (LDH) isoenzymes in the heart, kidneys, lungs, spleen, liver and skeletal muscle was performed in 4 species of carnivorous mammals (Mustelidae family): American mink (Mustela vison Schr.), polecat (Mustela putorius L.), sable (Martes zibellina L.) and pine marten (Martes martes L.). It was found that in the mink, unlike pure terrestrial mustelids (polecat, sable, pine marten), the anaerobic LDH-5 fraction was predominant in the LDH isoenzyme spectrum in the liver, skeletal muscle, lungs and spleen. In all species studied, aerobic B(H) subunits of LDH were found to prevail in the heart and kidney, whereas anaerobic A(M) subunits prevailed in the liver and spleen. The tissue- and species-specific features of LDH isoenzyme spectra revealed in different mustelids reflect the biochemical adaptation of the animals to environmental conditions.     

Amplification of DNA markers from scat samples of the least weasel<Emphasis Type="Italic">Mustela nivalis nivalis</Emphasis>

To test the feasibility of using field-collected scats as a source of DNA in the study of the least weaselMustela nivalis nivalis Linnaeus, 1766, DNA was extracted from scat samples collected from captive weasels using a modified extraction protocol. Using universal primers, the control region of the mitochondrial genome was successfully amplified from scat-extracted DNA. This amplification resulted in two products; one equivalent in size and sequence to the product obtained from tissue-extracted weasel DNA, and the other slightly larger and equivalent in size and sequence to the domestic house mouseMus musculus, the food source of the captive weasels. This demonstrates the reliability of DNA extraction from scats, as well as the possibility, under favourable circumstances, of identifying the prey species from the same samples. In addition, we attempted to amplify microsatellite loci from both tissue and scat-extracted DNA using six primer pairs designed for other mustelids, the American minkMustela vison and the wolverineGulo gulo. While three loci, Mvi57 (American mink), Ggu216 and Ggu234 (wolverine), were found to be polymorphic in the least weasel, amplification of these loci from the scat extracted DNA was only successful for approximately half of the samples. Although further work is needed, the present results suggest that it is possible to use scats as a source of DNA in field studies of the least weasel.     

MHC class II variation in the endangered European mink <Emphasis Type="Italic">Mustela lutreola</Emphasis> (L. 1761)—consequences for species conservation

The polymorphic major histocompatibility complex (MHC) has gained a specific relevance in pathogen resistance and mate choice. Particularly the antigen-binding site (ABS), encoded by exon 2 of the DRB class II gene, exhibits numerous alleles and extensive sequence variations between alleles. A lack of MHC variability has attributed to instances such as bottleneck effects or relaxed selection pressure and has a certain impact on the long-term viability of the species concerned. As a result of seriously decreased population density during the last century, the current population of the endangered European mink (Mustela lutreola, L. 1761) has suffered from geographic isolation. In this study, we amplified a partial sequence of the MHC class II DRB exon 2 (229 bp), assessed the degree of genetic variation and compared the variability with those of other Mustelidae. As a result, nine alleles were detected in 20 investigated individuals, which differ from each other by four to 25 nucleotide substitutions (two to 11 amino acid substitutions). Whilst an equal ratio for synonymous and non-synonymous substitutions was found inside the ABS, synonymous substitutions were significantly higher than non-synonymous substitutions in the non-ABS region. Results might indicate that no positive selection exists within the ex situ population of M. lutreola, at least in the analysed fragment. In addition, phylogenetic analyses support the trans-species model of evolution. Becker and Nieberg have contributed equally to this work.     

Late- and Post-Glacial history of the Mustelidae in Europe

1. Analyses of the subfossil records of mustelid species in Europe indicate specific differences in the pattern of temporal and spatial recolonization of central Europe after the maximum glaciation of the last glacial period. 2. For Meles meles, Martes martes and (with some reservations) Mustela putorius it can be seen that the populations were separated in several glacial refugia during the maximum glaciation of the Weichselian. In contrast, the European population of Lutra lutra was restricted to a single glacial refuge, which had not been clearly localized until now. 3. Besides the known glacial refugia of the Iberian Peninsula, Italian Peninsula and the Balkans, there is evidence of possible additional glacial refugia for mustelids near the Carpathians, in western Moldova and in the northern Pontic region. 4. Gulo gulo, Mustela nivalis, and Mustela erminea show adaptations for survival in Pleistocene conditions, but they were historically also distributed in the warmer areas of southern Europe. 5. Among the more thermophilic mustelid species, Mustela putorius is likely to have been the earliest immigrant following the maximum glaciation. Meles meles has been recorded in comparably early times and also seems to be relatively tolerant of climatic extremes. It is clear that Martes martes had already arrived in central Europe during the Allerød, in connection with the recolonization by birch and pine woods. Lutra lutra, by contrast, seems to have been an absolute Holocene immigrant.     

Geographic and host range of the nematode Soboliphyme baturini across Beringia

The nematode Soboliphyme baturini Petrov, 1930, was found to represent a single species with a relatively broad geographic range across Beringia and northwestern North America on the basis of the assessment of molecular sequence data for adult and juvenile parasites. Refuted are hypotheses suggesting that several cryptic species could be partitioned either among an array of mustelid definitive hosts or across the vast region that links North America and Eurasia. Host specificity for this species is examined on the basis of a comprehensive list for definitive hosts, derived from new field surveys and existing literature for S. baturini. Only 5 mustelids (Gulo gulo, Martes americana, M. caurina, M. zibellina, and Neovison vison) appear to have significant roles in the life history, persistence, and transmission of this nematode. Soboliphyme baturini readily switches among M. americana, M. caurina, Mustela erminea, or N. vison at any particular locality throughout its geographic range in North America, although Martes spp. could represent the source for nematodes in a broader array of mustelids. Molecular analyses (243 base pairs of mitochondrial gene nicotinamide dehydrogenase [ND4]) suggest that hypotheses for host specificity across an array of mustelid definitive hosts are not supported. The life cycle of S. baturini is explored through a review of diet literature for 2 marten species, M. americana and M. caurina, and other mustelids across the Holarctic. Shrews (Soricomorpha: Soricidae) comprise >8% of prey for these species of Martes, suggesting their putative role as paratenic hosts. Juvenile nematodes found in the diaphragms of soricids are genetically identical to adult S. baturini found in the stomachs of mustelids at the same locations in both Asia and North America, corroborating a role in transmission for species of Sorex.     

EcoRI- and BamHI-families of repeated sequences in mustelids

The restriction enzymes EcoRI and BamHI digest the genomic DNAs from six mustelids species Mustela lutreola, M. vision, M. erminea, M. sibirica, Vormela peregusna, producing repeated fragments varying in length. Some fragments were hybridized to chromosomes and restriction digests of DNAs from some mustelids and other mammals. The 0.7 kb EcoRI repeats from DNA of M. erminea are dispersed over chromosomes of carnivors. The 1.35, 1.9 and 2.7 kb BamHI repeats from DNA of polecat M. putorius furo are specific for mustelids. These repeats demonstrate interspecific variation in length and the number of copies. All BamHI repeats have no strict tandem organization. The 1.9 kb BamHI repeats are concentrated in the heterochromatic pericentromeric regions and additional chromosome arms. The 1.35 kb BamHI repeats are only located in the centromeric regions of chromosomes of five species and are absent in Vormela peregusna.     

Distyly and pollen dimorphism in<Emphasis Type="Italic"> Damnacanthus</Emphasis> (Rubiaceae)

We document distyly in Damnacanthus (Rubiaceae) and investigate pollen morphology in the genus. Within nine taxa in Japan (four species, four varieties and one form), five show distyly. Non-distylous taxa of Damnacanthus always have a long style and short stamens. We examined the pollen morphology of all taxa of Damnacanthus in Japan. The pollen grains of Damnacanthus are 3- to 5-orthocolporate or sometimes loxocolporate. Polymorphic pollen is sometimes observed even within a single flower. Pollen dimorphism is associated with distyly; pollen grains from short-styled (thrum) flowers are significantly larger than those from long-styled (pin) flowers, and the muri are smooth in pin flowers whereas the pollen grains of thrum flowers have minute granules on the top and/or on the sides. In non-distylous taxa, in which the style is longer than stamens, the muri are always provided with minute granules. Interestingly, the pollen grains with granules in the non-distylous taxa contrast with the pollen of the distylous taxa, because granulate pollen grains are found only in thrum flowers. Although Damnacanthus is a stenopalynous genus, the number of colpi is useful for delimiting taxa. Based on palynological characters, we conclude that Damnacanthus should be revised. Electronic Publication     

On co-existence,foraging strategy and the biogeography of weasels and stoats (Mustela nivalis and M. erminea) in Britain

Summary Mustela nivalis and M. erminea, two sympatric species of weasels of superficially similar appearance and habits, have different breeding and foraging strategies associated with the difference in their body size. M. nivalis is more efficient in exploiting small rodent prey, and can breed rapidly to take immediate advantage of rodent peaks, but is vulnerable to local extinction during rodent declines. M. erminea has more generalized food habits, and is the larger and probably the dominant species, but is limited by delayed implantation to producing only one litter a year. M. nivalis is therefore superior in exploitation competition, and erminea in interference competition. We offer the hypothesis that the co-existence of the two species is permitted by a balance of these competitive advantages determined, at a given time or place, by the heterogeneity of the environment and the distribution of the prey fauna. We use this hypothesis to explain cases where co-existence has either broken down or is not recorded (the results of simultaneous introductions to New Zealand and Terschelling Island, and of myxomatosis in Britain, and the distribution of nivalis and Erminea on the offshore islands of Britain). We argue that the diversity and size distribution of the prey fauna of an island (which are both related to its area and isolation) are important in deciding the species and size of mustelids surviving there; for example, we suggest that nivalis was present in Ireland in immediate post-glacial times but became extinct with the lemmings.     

Craniometrics of the orange mouse opossum<Emphasis Type="Italic">Marmosa xerophila</Emphasis> (Didelphimorphia: Didelphidae) in Venezuela

Skull size variation in the orange mouse opossumMarmosa xerophila Handley and Gordon, 1979 in Venezuela was analysed by sex and geographic location. Morphometric relationships between the species and the closely relatedM. robinsoni Bangs, 1898 were also studied. Results showed thatM. xerophila is a sexually dimorphic and geographically homogeneous species. Males had larger skulls than females, although dimorphism was mainly related to length, height, and some dental parameters. Interspecific comparisons revealed thatM. xerophila has a smaller skull thanM. robinsoni, even in the sympatric area where the smallest specimens ofM. robinsoni occur. Discriminant function analyses between these species, for males and females separately, provided accurate classification functions that allowed correct specific determination. In Venezuela,M. xerophila lives in arid lands with xerophilous thorny woodland and scrub, up to 90 m above see level.