Ultrastructure of spermiogenesis and the spermatozoon of Mesocestoides litteratus (Cestoda, Mesocestoididae).

This paper constitutes the first ultrastructural study of spermiogenesis and the spermatozoon of a cestode belonging to the family Mesocestoididae, Mesocestoides litteratus. Spermiogenesis in M. litteratus is characterised by a flagellar rotation and a proximodistal fusion. The zone of differentiation presents striated roots associated with the centrioles and also an intercentriolar body. The most interesting ultrastructural feature found in the mature spermatozoon of M. litteratus is the presence of parallel cortical microtubules. The spermatozoon also exhibits a single crest-like body and granules of glycogen. The pattern of spermiogenesis and the parallel position of cortical microtubules reveal the lack of concordance between M. litteratus and cyclophyllidean species studied to date in spermiogenesis and in the ultrastructural organisation of spermatozoon. This study provides new spermatological data and calls into question the validity of the current systematic position of mesocestoidids.     

Shedding of gravid proglottids and destrobilation in experimental infections of foxes with Mesocestoides leptothylacus Loos-Frank, 1980 (Cestoda)

The implications of the confused taxonomy of the genus Mesocestoides and the misuse of the name M. lineatus are described. In Southwest Germany rodents are intermediate hosts and red foxes are definitive hosts of M. leptothylacus. The shedding patterns of experimentally infected foxes showed that destrobilation occurs frequently and that there are long periods during which no gravid proglottids are shed at all. Lengths of worms can be taken as a measure of a possible crowding effect only when worms with gravid segments are present, i.e. at the end of the prepatent period (11 to 13 days) or at the beginning of a shedding period.     

First larval record of Mesocestoides in carnivora of Tenerife (Canary Islands)

Larvae of Mesocestoides sp. were recovered in Tenerife (Canary Islands) in 2004 from the peritoneal cavities of 2 domestic dogs and a domestic cat. Morphological and molecular identification were carried out. Mesocestoides litteratus from Vulpes vulpes was sequenced for the first time using the ITS-2 region (18S rDNA), and was included in the phylogenetic analysis to compare the sequence variability among these and other Mesocestoides spp. belonging to different carnivores. Phylogenetic studies were carried out based on maximum parsimony and neighbor-joining analysis. The results showed the relationships between these and other previously published Mesocestoides species. Moreover, it is demonstrated that Mesocestoides sp. from Tenerife comprises a previously unreported sequence. This is the first larval record of Mesocestoides sp. in domestic animals from Tenerife, Canary Islands, Spain.     

Helminths in the wolf, Canis lupus, from north-western Spain

Fifteen helminth species were collected from 47 wolves (Canis lupus ) which were surveyed from 1993 to 1999 in northwestern Spain. These included the trematode Alaria alata (2.1%); the cestodes Taenia hydatigena (44.7%), T. multiceps (29.8%), T. serialis (2.1%), Dipylidium caninum (6.4%) and Mesocestoides sp. aff. litteratus (4.2%); and the nematodes Pearsonema plica (7.4%), Trichuris vulpis (10.6%), Trichinella britovi (12.8%), Ancylostoma caninum (8.5%), Uncinaria stenocephala (51.1%), Toxocara canis (6.4%) Toxascaris leonina (4.2%), Angiostrongylus vasorum (2.1%) and Dirofilaria immitis (2.1%). Only two wolves were not infected. A single infection occurred in 28.9% of the cases, but the commonest infracommunity (31.1%) involved three species. The helminths Alaria alata, Taenia hydatigena, Mesocestoides sp. aff. litteratus, P. plica, Trichuris vulpis, and Ancylostoma caninum parasitizing C. lupus are reported for the first time in Spain. Taenia serialis and D. immitis are reported for the first time in wolves in Europe. Angiostrongylus vasorum represents a new host record for wolves. The helminth fauna of Spanish wolves is compared with that of other European wolf populations. Some epidemiological considerations of the helminth fauna of wolves in Spain and the health risk to humans are also discussed.     

Parasites present in foxes (Vulpes vulpes) of the province of Forli

In the period March 1983 - March 1984 a parasitological survey was carried out on 103 foxes killed in the Forli province (Italy). The parasites identified were: Toxocara canis (45.6%); Uncinaria stenocephala (14.6%); Mesocestoides lineatus (9.7%); Dipylidium caninum (2.9%); Taenia crassiceps (2.9%); Trichuris vulpis (2.9%). Out of all the cestodes found in 7 animals the authors identified only genus Taenia since their preservation conditions were not optimal. Other 13 subjects contained many cestodes similar to T. hydatigena, but considerably shorter in the mean length (20 cm vs 200). In a fecal sample the authors found a species of coccidium whose features do not correspond to any of those described in foxes, therefore it was called Eimeria sp. Finally, the autopsies' results were compared with coprological ones in order to asses their reliability.     

Helminths of red foxes (Vulpes vulpes) and raccoon dogs (Nyctereutes procyonoides) in Lithuania

Red foxes and raccoon dogs are hosts for a wide range of parasites including important zoonotic helminths. The raccoon dog has recently invaded into Europe from the east. The contribution of this exotic species to the epidemiology of parasitic diseases, particularly parasitic zoonoses is unknown. The helminth fauna and the abundance of helminth infections were determined in 310 carcasses of hunted red foxes and 99 of raccoon dogs from Lithuania. Both species were highly infected with Alaria alata (94·8% and 96·5% respectively) and Trichinella spp. (46·6% and 29·3%). High and significantly different prevalences in foxes and raccoon dogs were found for Eucoleus aerophilus (97·1% and 30·2% respectively), Crenosoma vulpis (53·8% and 15·1%), Capillaria plica (93·3% and 11·3%), C. putorii (29·4% and 51·5%), Toxocara canis (40·5% and 17·6%) and Uncinaria stenocephala (76·9% and 98·8%). The prevalences of the rodent-transmitted cestodes Echinococcus multilocularis, Taenia polyacantha, T. crassiceps and Mesocestoides spp. were significantly higher in foxes than in raccoon dogs. The abundances of E. multilocularis, Mesocestoides, Taenia, C. plica and E. aerophilus were higher in foxes than those in raccoon dogs. A. alata, U. stenocephala, C. putorii and Echinostomatidae had higher abundances in raccoon dogs. The difference in prevalence and abundance of helminths in both animals may reflect differences in host ecology and susceptibility. The data are consistent with red foxes playing a more important role than raccoon dogs in the transmission of E. multilocularis in Lithuania.     

Mesocestoides lineatus (Goeze, 1782) (Mesocestoididae): new data on sperm ultrastructure

Spermiogenesis and the ultrastructural characters of the spermatozoon of Mesocestoides lineatus are described by means of transmission electron microscopy, including cytochemical analysis for glycogen. Materials were obtained from a golden hamster (Mesocricetus auratus) after experimental infection with tetrathyridia metacestodes obtained from naturally infected lizards (Anolis carolinensis) from Louisiana. Spermiogenesis in M. lineatus is characterized by the orthogonal growth of a free flagellum, a flagellar rotation, and a proximodistal fusion. The zone of differentiation contains 2 centrioles associated with striated rootlets and a reduced intercentriolar body. The mature spermatozoon of M. lineatus lacks a mitochondrion, and it is characterized by the presence of (1) a single, spiraled, crested body 150 nm thick; (2) a single axoneme of the 9+'1' pattern of trepaxonematan Platyhelminthes; (3) a parallel and reduced row of submembranous cortical microtubules; (4) a spiraled cordon of glycogen granules; and (5) a spiraled nucleus encircling the axoneme.     

Helminth parasitism in martens (Martes americana) and ermines (Mustela erminea) from Washington, with comments on the distribution of Trichinella spiralis

Helminths are reported for the first time from ermines (Mustela erminea) and martens (Martes americana) in Washington (USA). Among 22 adult ermines, 41% were infected by one or more of five species (Taenia mustelae, Alaria mustelae, Molineus patens, M. mustelae and Trichinella spiralis). Among 78 adult martens from three geographic localities, the prevalence was 83%. Nine species were identified (Mesocestoides sp., T. mustelae and T. martis americana, Euryhelmis squamula, M. patens, Baylisascaris devosi, Physaloptera sp., Soboliphyme baturini and T. spiralis). Trichinella spiralis occurred with a maximum prevalence of 50% in martens, but only occurred in 9% of ermines. Compression and digestion techniques provided a similar estimate of prevalence of T. spiralis, yet neither was entirely accurate in identifying all infected hosts. The species richness of the helminth community of martens in Washington was greater than that reported from other regions of North America.     

Hunting to extinction: biology and regional economy influence extinction risk and the impact of hunting in artiodactyls

Half of all artiodactyls (even-toed hoofed mammals) are threatened with extinction, around double the mammalian average. Here, using a complete species-level phylogeny, we construct a multivariate model to assess for the first time which intrinsic (biological) and extrinsic (anthropogenic and environmental) factors influence variation in extinction risk in artiodactyls. Globally artiodactyls at greatest risk live in economically less developed areas, have older weaning ages and smaller geographical ranges. Our findings suggest that identifying predictors of threat is complicated by interactions between both biological and anthropogenic factors, resulting in differential responses to threatening processes. Artiodactyl species that experience unregulated hunting live in significantly less economically developed areas than those that are not hunted; however, hunted species are more susceptible to extinction if they have slower reproductive rates (older weaning ages). In contrast, risk in non-hunted artiodactyls is unrelated to reproductive rate and more closely associated with the economic development of the region in which they live.     

Echinococcus multilocularis in the red fox Vulpes vulpes from the East Carpathian region of Poland and the Slovak Republic

The occurrence of Echinococcus multilocularis in the Poland-Slovak frontier zone of the East Carpathian region was assessed, for comparison with that in adjacent regions in both countries. A total of 392 red foxes from Poland and 427 red foxes from the Slovak Republic were examined from 2001 to 2004. Significant differences in prevalences were observed in foxes captured from the borderland and adjacent zones in both countries. The mean prevalence of E. multilocularis in the Polish borderland reached 45.7+/-18.6% and in the Slovak border 35.0+/-10.7%. In both countries, the prevalence of E. multilocularis in red foxes from adjacent districts, outside the frontier Carpathian region, was considerably lower (18.9+/-9.2% in Poland and 20.8+/-9.0% in Slovakia). These differences are probably due to geomorphological and ecological factors, which contribute to the survival of the tapeworm eggs and the subsequent spread of infection. The Carpathian regions of northeast Slovakia and southeast Poland are characterized by specific climatic conditions such as low mean annual air temperatures, low temperatures in active soil surfaces, high soil humidities and a high mean annual rainfall.     

Ants as first intermediate hosts of Mesocestoides on San Miguel Island, USA

This study tested the hypotheses that ants (Formicidae) function as a first intermediate host of Mesocestoides (Cestoda: Mesocestoididae) and that deer mice (Peromyscus maniculatus) develop metacestode infections after ingesting cysticercoid or procercoid-infected ants. Field studies were conducted at an island fox (Urocyon littoralis littoralis) breeding facility located on San Miguel Island, California Channel Islands National Park, USA, where > 40% of captive foxes were infected with adult Mesocestoides. Eight percent (8%) of deer mice at the fox pen site were infected with Mesocestoides metacestodes while none were infected at a distant site where foxes were absent (campground), thereby indicating the potential localized presence of a first intermediate host. To test whether ants from San Miguel Island contained Mesocestoides DNA, a polymerase chain reaction (PCR)-based diagnostic assay was developed using nested primers that could detect a single hexacanth larva within pooled samples of ten ants. Ants (Lasius niger and Tapinoma sessile) collected near the fox breeding facility were tested using the nested-PCR assay. Seven of 223 pooled samples of L. niger (3.1%) and 2 of 84 pooled samples of T. sessile (2.4%) tested positive for Mesocestoides DNA, while none of the ants were positive at the campground site. Positive samples were sequenced and found to match DNA sequences from Mesocestoides obtained from island fox and deer mice. Finally, to determine whether ants function as a first intermediate host for Mesocestoides, colony-raised deer mice (n = 47) were fed L. niger (n = 3860) or T. sessile (n = 339) collected from the San Miguel Island fox breeding facility. No mouse became infected with Mesocestoides metacestodes after ingesting ants. While both L. niger and T. sessile from SMI were positive for Mesocestoides DNA, they were not infective to deer mice in the laboratory.     

Social organization,survival, and dispersal of cape foxes (Vulpes chama) in South Africa

We monitored 20 cape foxes (Vulpes chama) to determine the social organization, survival, and dispersal of this species on two sites in South Africa from 2005 to 2008. Cape foxes were socially monogamous and territorial, with annual home ranges of mated pairs (n = 8) overlapping 80% on average, compared to a mean overlap of 3% between foxes in adjacent ranges. At least 2 pairs remained associated for >1 breeding season, and both sexes exhibited strong site fidelity, as home ranges in consecutive years overlapped 58–98%. Members of mated pairs never foraged together, however they used the same or nearby (<100 m apart) day rests 81% of the time when pups were 0–4 months of age, but only 28% of the time during other months of the year. Dispersal was male biased, as all juvenile males (n = 6) dispersed when 9–11.5 months old, whereas 3 of 4 juvenile females remained philopatric as either breeders or non-breeding associates. At least 6 foxes bred as yearlings (3 F, 3 M), indicating cape foxes have high reproductive potential. Two adult females maintained their territories after their mates died, whereas two adult males dispersed soon after their mates died, indicating cape foxes likely have a female-based social organization. Annual survival was 0.64, and predation from larger carnivores, primarily black-backed jackals (Canis mesomelas), was responsible for 71% of mortalities. Our results provided empirical support for previous hypotheses regarding the relationship between body size and life-history patterns in Canidae, as several ecological parameters of cape foxes were similar to that of other small (<6 kg) canid species, especially Vulpes species inhabiting arid and semi-arid environments.     

Pre-and post-zygotic reproductive isolation between co-occurring Mussaenda pubescens var.alba and M. shikokiana(Rubiaceae)

Reproductive isolation is a fundamental requirement for speciation and includes several sequential stages.Few studies have determined the relative contributions of pre-and post-zygotic reproductive isolation in plants,especially between relative species with clear differentiation in flower form.To investigate the mechanisms responsible for reproductive isolation in sympatric Mussaenda pubescens var.alba and Mussaenda shikokiana(Rubiaceae)in Guangxi Province,China,we made observations of flowering phenology,patterns of insect visitation,and conducted pollination experiments,including artificial hybridization.The two species had overlapping flowering times and were pollinated by overlapping pollinators;however,their relative importance differed significantly with M.pubescens visited more commonly by bees and M.shikokiana more frequently by butterflies.Using vegetative and floral characters and molecular evidence based on nuclear ribosomal internal and external transcribed spacer regions we detected seven naturally occurring hybrids among a sample of approximately 125 individuals.Hybrids werecharacterized by morphologies that most closely resembled their maternal parents based on chloroplast evidence.Studies of artificially synthesized and natural hybrids demonstrated that hybrid seed had very low germination rates and naturally occurring hybrids exhibited pollen sterility.Post-zygotic reproductive isolating mechanisms play a primary role in limiting gene exchange between co-occurring species and maintaining species integrity in areas of sympatry.     

Helminthologic survey of the wolf (Canis lupus) in Estonia, with an emphasis on Echinococcus granulosus

Carcasses of 26 wolves were collected during the 2000/2001 and 2003/2004 hunting seasons and examined for helminths. Thirteen helminth species were recorded: one trematode (Alaria alata), seven cestodes (Diphyllobothrium latum, Mesocestoides lineatus, Taenia hydatigena, Taenia multiceps, Taenia ovis, Taenia pisiformis, and Echinococcus granulosus), and five nematode species (Uncinaria stenocephala, Toxascaris leonina, Toxocara canis, Trichinella nativa, and Trichinella britovi). The most common species were A. alata and U. stenocephala. Mature Echinococcus granulosus was found and described for the first time in Estonia, and its identity verified using PCR-RFLP analysis. Sequencing a fragment of the mitochondrial DNA NADH dehydrogenase 1 (mtND1) gene showed that the E. granulosus strain from Estonia was identical to strain G10, recently characterized in reindeer and moose in Finland.     

The parasites of the badger (Meles meles) in the north of Mugello (Florence, Italy)

During the period January 1993-June 1994, a parasitological survey was carried out on 19 badgers (Meles meles) road killed in Northern Mugello (Florence). The following helminths (together with their prevalence) were isolated and classified: Uncinaria criniformis (84.2%); Capillaria sp. (31.6%); Molineus patens (21.1%); Mesocestoides melesi (21.1%); Aelurostrongylus falciformis (52.6%); Crenosoma melesi (21.1%). According to results, only sex related differences in prevalence were studied. The parasite biocenosis is composed exclusively by dominant and codominant species. Mesocestoides melesi represents the first record for Italy. All the species found fitted a negative binomial distribution.     

Infection of red foxes with Echinococcus multilocularis in western Switzerland

In the Jura mountains, Plateau and Alps of western Switzerland important variations in the prevalence of Echinococcus multilocularis infection in red foxes were observed between geographical areas from 1990 to 1995. The Jura mountains and the Plateau had higher mean prevalence levels than the Alps with 30.6, 32.4 and 18.8%, respectively. The highest rate was recorded in the Plateau in the canton of Fribourg with a prevalence of 52.3%. The prevalence of E. multilocularis infection in foxes in the alpine canton of Valais was the lowest (7.1%). Juvenile foxes were found to be more susceptible to E. multilocularis than adults. Adult foxes were less heavily infected in summer and autumn, while the prevalence in juveniles (less than 1 year old) increased between the spring and winter, when they are more than 6 months old. The retrospective data relate to the beginning of the 1990s, since when a drastic prevalence increase of E. multilocularis infection in foxes has occurred in several regions of Europe. Nevertheless, the study is a major contribution to the epidemiological situation of E. multilocularis in central Europe, in that it contains valuable information on spatial distribution and seasonal differences in different age groups of foxes.     

Differentiation of closely related oyster fungi Pleurotus pulmonarius and P. ostreatus by mating and molecular markers

Classical matings and RAPD-PCR analysis were used to differentiate two closely related basidial fungi, Pleurotus pulmonarius and P. ostreatus, which are widespread in Russian forest biocenoses with moderate climate. Monokaryon-monokaryon (mon-mon) and dikaryon--monokaryon (di-mon) matings demonstrated complete reproductive isolation of the two species, which have partly overlapping morphological traits. The prevalence of a particular species in nature was shown to depend to a great extent on the natural conditions, namely, the day and night temperature ranges. The clustering of natural Pleurotus strains displayed two trends: one was associated with natural reproductive isolation of the two species (D = 0.61) and the other, with the geographical factor (D = 0.39). A relatively recent origin is suggested for the divergence of the two species and the reproductive barrier between them. Adaptation to natural conditions was considered to be the main factor causing the divergence of natural Pleurotus populations and, eventually, allopatric speciation.     

Patterns of life-history traits in open-nesting palearctic passerines as a function of the climatic variation of their ranges

Latitude, a surrogate of climatic conditions, is commonly used in the examination of life-history variation. However, the climatic mechanisms underlying latitudinal life-history variation have only rarely been tested. Here, we test whether the number of climates to which species are subjected in their ranges predicts geographical life-history variation. In particular, we examine whether eurytopic species, the range of which covers more climates, show different reproductive effort to stenotopic species, which are distributed over climatically more homogeneous environments. We examined female body mass, egg mass controlled for female body mass, clutch size and the number of breeding attempts per season for 34 sedentary and short-distance migratory passerine species of the Western Palearctic. For each species, we assessed how many climate zones extend over the species' wintering and breeding ranges. We found that avian body mass, and also clutch size, significantly increases with the number of climatic zones extended over the species' wintering range. In turn, species whose breeding ranges span more climates show more breeding attempts per season. Whereas the mass of a single egg declines, clutch size increases with increasing climatic variation in breeding ranges. Our study suggests that the level of climatic variation over species' ranges during and outside the breeding season might be responsible for variation in life-history traits in open-nesting Western Palearctic passerines.     

The eastern Pacific species of Bathygobius (Perciformes: Gobiidae)

The circumtropical gobiid genus Bathygobius Bleeker is defined and three Eastern Pacific species are redescribed, with first dorsal fin pattern and postorbital blotches being shown to be additional characters of diagnostic value. Two mainland species are recognised, the Mexican-Panamanian B. ramosus Ginsburg 1947 and the Panamanian B. andrei (Sauvage 1880). B. ramosus is now reported from Clarión Island, Revillagigedos, and also from Cocos Island. Meristic variation of ramosus is tabulated for local populations and PCA analysis of their morphometry suggests regional differentiation in this species, with Tres Marias and Revillagigedos populations clustering away from mainland and Montuosa material. An insular species, B. lineatus (Jenyns 1842) from the Galapagos is defined, with B. arundelii (Garman 1899) from Clipperton Island and B. l. lupinus Ginsburg 1947 from Lobos de Afuera, off Peru, placed as nominal subspecies of lineatus. This species resembles the Indo-west Pacific B. fuscus and Atlantic basin B. soporator more closely than it does ramosus and andrei and may be the product of transpacific dispersal. A similar origin for B. ramosus is discussed but it seems more likely that both B. ramosus and B. andrei have Caribbean sister species.     

Some aspects of intraspecific variability of the closely related species of the Dermacentor marginatus complex (Acari: Ixodidae) as demonstration of microevolutionary process

Individual and geographical variability of male conscutum pattern in five closely related species of the Dermacentor marginatus complex (D. marginatus, D. ushakovae, D. niveus, D. silvarum, D. nuttalli) has been examined. The pattern has been examined in three to six geographical samples within each specific distribution range. It was established that the pattern of the conscutum central area is subjected to individual and geographical variability on an extreme degree and gives very few intraspecific differential characters, but it shows interspecific differences in some cases. However the dark patches of marginal flank (npkappadelta and 3deltakappa respectively, see Fig. 3) show statistically significant differences in length in all geographical samples of the first four species. Characteristic features of ixodid ticks morpogenesis rule out to a considerable extent the possibility to trace geographical variability of the same characters by all stages of ontogenesis. In these cases, when it is possible, the tendencies to variability on different stages do not always coincide. There is no coordination within the species in the degree of differences of examined geographical samples by pattern and morphological characters, i. e. very complex polymorphis is observed. In the context of the evolution that kind of polymorphism of the geographical samples has provided the species with high adaptive potential for conquest of the extensive range and maintaining large numbers. The question of allopatric speciation of the closely related D. marginatus-D. silvarum with small secondary area of transgression their ranges, and sympatric speciation of the D. ushakovae-D. niveus is postulated.