Interactions and associations between age and sex classes in mouflon sheep (Ovis gmelini) during winter

The fact that sexual segregation can occur in wild ruminants independently of sex-related differences in habitat use suggests that it results at least partly from social mechanisms. One of the simplest mechanisms which can be hypothesised is that individuals avoid the congener classes which frequently try to interact with them (be these interactions 'agonistic' or 'sexual', since courtship behaviour components typically induce withdrawal when performed outside the rut). The aim of the present study was to test, in mouflon sheep (Ovis gmelini), whether the age-sex classes which exchange frequent interactions on meeting occur rarely inside the same groups. Observations were made during winter, on a small population in Germany. Interactions were recorded at an attractive site where all age-sex classes met daily. Foot transects were conducted in parallel over the whole study area in order to determine group composition. As expected, adults of different sexes exchanged frequent interactions at the attractive site and were rarely found in the same groups under free-ranging conditions, while adult females, who interacted little with one another, were quite frequently associated. However, adult males simultaneously exhibited the highest rate of interaction at the attractive site and the highest frequency of association under free-ranging conditions. Unlike female-female and male-female pairs, in which interactions with a clear initiator and a clear recipient predominated, male-male pairs exchanged often spectacular but 'symmetrical' interactions (during which the two individuals behaved in the same way). The hypothesis that sexual segregation results from the avoidance of the congener classes which frequently engage interactions only holds for females. Adult rams interact frequently and seek companions with whom symmetrical interactions can be performed.     

Agonistic and proximity patterns in enclosed mouflon (Ovis gmelini) ewes in relation to age, reproductive status and kinship

Agonistic and proximity patterns of mouflon sheep (Ovis gmelini) were studied in a group of enclosed females during two lambing periods. A non-random linear-tending hierarchy almost stable over the 2-years was found. Age was correlated to social rank and to the distribution of agonistic acts by females. The rank of the yearling females was linked to the rank of their mothers. The age of the animal and the degree of relatedness with its congeners appeared as main determinants of the proximity patterns of ewes. Strong associations between closely related females (especially mothers and daughters), brought out the existence of a familial structure in mouflon. Otherwise, we found a strong inter-attraction between yearlings, which received a large number of aggressions from older females. That revealed peer grouping superimposed on familial structures. Age also seemed to influence ‘sociality’ of females, older females tending to associate less with conspecifics than younger ones.     

Male harassment drives females to alter habitat use and leads to segregation of the sexes

Sexual conflict is ubiquitous across taxa. It often results in male harassment of females for mating opportunities that are costly for females, in some cases reducing reproductive success and increasing mortality. One strategy that females may employ to avoid sexual harassment is to segregate spatially from males. In fact, we do find sexual segregation in habitat use in species that have high levels of sexual conflict; however, the role of sexual harassment in driving such segregation remains poorly understood. Here, we demonstrate experimentally in a population of wild Trinidadian guppies Poecilia reticulata that male sexual harassment drives females into habitats that they otherwise do not prefer to occupy. In support of the social factors hypothesis for sexual segregation, which states that social factors such as harassment drive sexual segregation, this female behaviour leads to segregation of the sexes. In the presence of males, females actively select areas of high predation risk, but low male presence, and thus trade off increased predation risk against reduced sexual harassment.     

Influence of age on the relationship between annual changes in horn growth rate and prolactin secretion in the European mouflon (Ovis gmelini musimon)

Annual variations in the growth of horns, and their correlation with seasonal changes of testicular size, and prolactin (PRL) and melatonin secretion were monitored in six pubertal mouflon rams living in their original latitude (40 degrees N). Mouflons born and maintained under captive conditions were classified in two age classes: sub-adult (2 years; n=3) and adult (> or =3 years; n=3). The rate of horn growth was greater (P <0.001) in sub-adult than in adult mouflon rams. Horn growth was influenced by season in both adult and sub-adult mouflons (P <0.05) with largest monthly growth occurring in spring and summer. Seasonal variations of plasma PRL concentrations were correlated with horn growth in adult, but not in sub-adult mouflon rams. The rate of horn growth was inversely correlated with testicular size (r=-0.5, P=0.07). Seasonal changes in the amplitude of the daily melatonin rhythm in solstices and equinoxes were observed, which were not correlated with variations in the rate of horn growth. These results provide support for a possible role of PRL in the control of growth of horns in the adult mouflon.     

Maternal condition and offspring sex ratio in polygynous ungulates: a case study of bighorn sheep

The Trivers and Willard model (TWM) predicts that for sexuallydimorphic polygynous mammals, mothers able to provide a highlevel of care should bias offspring sex ratio in favor of sons.Contradictory results of empirical studies, however, suggestthat selective pressures for adaptive offspring sex ratio varywith species and environmental conditions. We report the resultsof a 29-year study of marked bighorn sheep (Ovis canadensis)in a population that underwent wide changes in density and wheremost females were weighed each year. Lamb sex ratio was independentof absolute ewe mass and yearly deviations from individual orpopulation average mass, but there was a nonsignificant trendtowards fewer males being born at high population density. Bighornsheep satisfy all the assumptions of the TWM but not its prediction:lamb sex ratio is independent of maternal ability to providecare. Recent hypotheses to explain the lack of relationshipbetween maternal condition and offspring sex in ungulates areunlikely to apply to bighorn sheep. We suggest that the TWMmay only apply when social rank strongly affects the abilityto provide maternal care. Those circumstances are likely tooccur for only a few species and within a narrow range of environmentalconditions.     

Mining activity and habitat use by mountain sheep (<Emphasis Type="Italic">Ovis canadensis</Emphasis>)

We studied mountain sheep in the vicinity of three high-wall limestone mines in San Bernardino County, CA, USA to evaluate factors that influenced habitat use and, specifically, to investigate the influence of mining activity on distribution of those specialized ungulates. We used aerial telemetry data to estimate a resource selection function by fitting a logistic regression model and then comparing environmental characteristics at observed sheep locations to those at random locations. Distribution of mountain sheep was most influenced by a fire in 1999 that resulted in an area they avoided. Mountain sheep used steeper slopes, areas of lower terrain roughness, higher elevations, and areas closer to escape terrain than were random points. In contrast, sheep avoided areas near roads (federal and state highways, local roads, and off-road vehicle trails) but used areas near hiking trails and a railway. Water sources had the smallest effect of the factors considered, with sheep being associated with areas further from water points than were random locations. The disturbed area associated with the mines had a moderate influence on distribution, with sheep being associated with areas closer to the mine than were random points. Mining activities can alter terrain features and vegetation structure or composition in a way that promotes occupancy by sheep if they create steep slopes and rugged terrain (escape terrain) or reduce vegetation density or height (i.e., improve visibility). Whether increased occupancy reflects a benefit depends on the demographic responses of those sheep to the resources and conditions available on mine sites; information about those responses remains lacking.     

Molecular DNA identity of the mouflon of Cyprus (Ovis orientalis ophion,Bovidae): Near Eastern origin and divergence from Western Mediterranean conspecific populations

The mouflon population of Cyprus (Ovis orientalis ophion) comprises historically preserved feral descendants of sheep domesticated during the Neolithic. We determined genetic identity of this taxon in order to elucidate its systematic placement and enforce its protection. We used 12 loci of microsatellite DNA to infer genetic relationships between the Cypriot mouflon and either long-time isolated (Corsica, Sardinia) or recently introduced (central Italy) European mouflons (O. o. musimon). We also sequenced the mitochondrial DNA (mtDNA) Cytochrome-b gene to infer the origin of the Cypriot mouflon including many National Centre for Biotechnology Information (NCBI) entries of European and Near Eastern conspecifics. Microsatellites disclosed net divergence between Western Mediterranean and Cypriot mouflon. The latter was included in the highly heterogeneous Near Eastern O. orientalis mtDNA group, Iran representing the most credited region as the source for its ancient introduction to Cyprus. Both international and national legislation protect the mouflon of Cyprus as a wild taxon (O. o. ophion). However, the IUCN Red List of Threatened Species and NCBI include the Cypriot mouflon as subspecies of its respective domestic species, the sheep (O. aries). Unfortunately, people charged with crime against protected mouflon may benefit from such taxonomic inconsistency between legislation and databases, as the latter can frustrate molecular DNA forensic outcomes. Until a definitive light can be shed on Near Eastern O. orientalis systematics, we suggest that the Cypriot mouflon should be unvaryingly referred to as O. o. ophion in order not to impair conservation in the country where it resides.     

Habitat use and movements of plains zebra (Equus burchelli) in response to predation danger from lions

Prey species must adapt their behavior to avoid predation. Asa key prey item for lions (Panthera leo), plains zebras (Equusburchelli) were expected to respond to immediate threats posedby lions in their area. In addition, zebras were predicted toexhibit behavior tuned to reduce the potential for encounterswith lions, by modifying their movement patterns in the timesof day and habitats of greatest lion danger. We studied a populationof approximately 600 plains zebra living in Ol Pejeta Conservancy,Kenya. We found that zebra abundance on or near a grasslandpatch was lower if lions had also been observed on that patchduring the same day. Predation danger was highest in grasslandhabitat during the night, when lions were more active. Zebrasightings and global positioning system radio collar data indicatedthat zebras also reduced their use of grassland at night, insteadusing more woodland habitat. Zebras moved faster and took sharperturns in grassland at night. It is hypothesized that these moreerratic movements assist zebras in avoiding detection or captureby lions.     

The dietary overlap between red kangaroos (Macropus rufus) and sheep (Ovis aries) in the arid rangelands of Australia

Abstract The interaction between red kangaroos and sheep in the more arid areas of Australia was examined by means of a large-scale manipulative experiment. The diets of red kangaroos and sheep grazing together and separately in large paddocks were studied to assess whether competition for food might influence diet selection in these species. Diets and the amount of intra- and interspecific dietary overlap varied in accordance with pasture conditions. At pasture biomasses ranging from 50 to 200 g m^?2 (dry weight [wt]), the diets of red kangaroos and sheep overlapped by 58–73%, with forbs and grasses being the major items in the diets of both species. The diets of both sheep and red kangaroos under different experimental regimes were similar. In dry times (pasture biomass 40–50 g m^?2 (dry wt) more shrubs were eaten by both species and the amount of dietary overlap tended to be lower (52–66%). The diets of kangaroos were similar between paddocks. However, in paddocks containing both species sheep consumed proportionately more chenopodaceous shrubs and fewer grasses than those in ‘kangaroo-free’ paddocks.     

Genetic polymorphism of serum vitamin D-binding protein (GC) in sheep and mouflon

One-dimensional polyacrylamide gel electrophoresis (1D PAGE) followed by immunoblotting revealed genetic polymorphism of GC protein in sheep (variants F, S, V) and mouflon (variants F and S, apparently identical to F and S of sheep). The frequency of Gcs allele ranged from 0.84 to 1.0 in the 12 breeds of sheep studied. GcV allele was observed only in Tsigai breed with a frequency of 0.017.     

Serum biochemical values of mouflon (<Emphasis Type=Italic>Ovis orientalis musimon</Emphasis>) according to age and sex

Interest for breeding mouflons in Europe is growing by the day, so it is important to extend our knowledge regarding their physiology. To establish reference intervals of biochemical values for mouflon (Ovis orientalis musimon), serum samples from 35 males and 26 females were analyzed using the automatic analyzer Olympus AU 640 for 22 serum biochemistry parameters. All mouflons aged from 1 to 4 years were apparently healthy and in good body condition and kept at an average altitude of 87 m (45°4′N, 18°6′E). Obtained results were tested according to age and sex categories by the repeated measurement model with Tukey’s post hoc test. Data showed a significantly higher (P < 0.01) concentration of total serum bilirubin and chloride in adult pregnant female mouflons compared to adult male mouflons. A significantly higher (P < 0.01) value of sodium and a lower (P < 0.01) value of serum phosphate in adult pregnant female mouflons compared to adult male mouflons have been determined. These data provide the baseline information about serum biochemical parameters which can be used to manage the health in mouflons.     

Quantitative trait loci (QTL) mapping of resistance to strongyles and coccidia in the free-living Soay sheep (Ovis aries)

A genome-wide scan was performed to detect quantitative trait loci (QTL) for resistance to gastrointestinal parasites and ectoparasitic keds segregating in the free-living Soay sheep population on St. Kilda (UK). The mapping panel consisted of a single pedigree of 882 individuals of which 588 were genotyped. The Soay linkage map used for the scans comprised 251 markers covering the whole genome at average spacing of 15cM. The traits here investigated were the strongyle faecal egg count (FEC), the coccidia faecal oocyst count (FOC) and a count of keds (Melophagus ovinus). QTL mapping was performed by means of variance component analysis so that the genetic parameters of the study traits were also estimated and compared with previous studies in Soay and domestic sheep. Strongyle FEC and coccidia FOC showed moderate heritability (h(2)=0.26 and 0.22, respectively) in lambs but low heritability in adults (h(2)<0.10). Ked count appeared to have very low h(2) in both lambs and adults. Genome scans were performed for the traits with moderate heritability and two genomic regions reached the level of suggestive linkage for coccidia FOC in lambs (logarithm of the odds=2.68 and 2.21 on chromosomes 3 and X, respectively). We believe this is the first study to report a QTL search for parasite resistance in a free-living animal population and therefore may represent a useful reference for similar studies aimed at understanding the genetics of host-parasite co-evolution in the wild.     

Home range and habitat use by Geoffroy's cat (Oncifelis geoffroyi) in a wet grassland in Argentina

Geoffroy's cat Oncifelis geoffroyi is a little-known South American small felid. We report data on the spatial ecology of four adults (two males and two females) that were radiotracked in an area of wet grassland of the Argentine Pampas from February 2000 to April 2001. The mean home range size varied from 248 ha [90% minimum convex polygon (MCP)] to 342 ha (100% MCP), with male home ranges c . 2.5 larger than those of females. Home range overlap averaged 44.7%, and was more extensive between males than between females but it decreased markedly when outliers were excluded. Forest patches were used more than expected by their availability within home ranges. These patches hosted many large defecation sites, possibly acting as 'communication centres' where information was exchanged among individuals in the form of scent marks. Despite the lack of a clear preference for tall grasslands, this was the most frequently used habitat. We argue that natural grasslands in the Pampas ecoregion are important for O. geoffroyi and that their alteration can affect the conservation status of this cat. The comparison of our data with those reported previously suggests that Geoffroy's cat can show a certain degree of flexibility in its spatial behaviour.     

Ecological divergence and habitat isolation between two migratory forms of Japanese threespine stickleback (Gasterosteus aculeatus)

When two closely related species migrate to divergent spawning sites, divergent use of spawning habitats can directly reduce heterospecific mating. Furthermore, adaptations to divergent spawning habitats can promote speciation as a by‐product of ecological divergence. Here, we investigated habitat isolation and ecological divergence between two anadromous forms of threespine stickleback (Gasterosteus aculeatus), the Japan Sea and Pacific Ocean forms. In several coastal regions of eastern Hokkaido, Japan, these forms migrate to the same watershed to spawn. Our field surveys in a single watershed revealed that segregation of distinct spawning sites between the two forms was maintained within the watershed across multiple years. These spawning sites diverged in salinity and predator composition. Morphological and physiological divergence between the forms also occurs in the direction predicted by ecological differences between the spawning sites. Our data indicate that migration into divergent spawning habitats can be an important mechanism contributing to speciation and phenotypic divergence in anadromous fishes.     

Genotype and Phenotype of Echinococcus granulosus Derived from Wild Sheep (Ovis orientalis) in Iran

The aim of the present study is to determine the characteristics of genotype and phenotype of Echinococcus granulosus derived from wild sheep and to compare them with the strains of E. granulosus sensu stricto (sheep-dog) and E. granulosus camel strain (camel-dog) in Iran. In Khojir National Park, near Tehran, Iran, a fertile hydatid cyst was recently found in the liver of a dead wild sheep (Ovis orientalis). The number of protoscolices (n=6,000) proved enough for an experimental infection in a dog. The characteristics of large and small hooks of metacestode were statistically determined as the sensu stricto strain but not the camel strain (P=0.5). To determine E. granulosus genotype, 20 adult worms of this type were collected from the infected dog. The second internal transcribed spacer (ITS2) of the nuclear ribosomal DNA (rDNA) and cytochrome c oxidase 1 subunit (COX1) of the mitochondrial DNA were amplified from individual adult worm by PCR. Subsequently, the PCR product was sequenced by Sanger method. The lengths of ITS2 and COX1 sequences were 378 and 857 bp, respectively, for all the sequenced samples. The amplified DNA sequences from both ribosomal and mitochondrial genes were highly similar (99% and 98%, respectively) to that of the ovine strain in the GenBank database. The results of the present study indicate that the morpho-molecular features and characteristics of E. granulosus in the Iranian wild sheep are the same as those of the sheep-dog E. granulosus sensu stricto strain.     

牛科(哺乳纲:偶蹄目)动物与生境利用有关的适应形态模式

对广义牛科动物颅后骨骼的多元变量分析揭示了牛科生境利用和体型之间的骨学特征。利用逐步分辨分析方法和一个基于机器学习的决策树方法鉴别了每种生境中牛科动物颅后解剖结构的形态特征。从110个广义牛科动物测量了43个指标进行了这项分析。利用所有主要肢骨测量值和以单根肢骨测量为主的测量值获得的分辨函数和决策树可以完美地区分适应开阔生境、森林和山地的牛科动物(在所有分析中得到了100 %正确的再分类)。由于调整的函数仅涉及到很小的颅后骨骼测量集,这些函数可以应用于研究考古学和古生物学发掘物中保存的不完整标本。这些表征生境利用的生态适应函数与那些用颅齿部性状建立、用于推测牛科动物食物选择的函数结合,具有刻画已灭绝的分类类群的古个体生态学和重建古环境的潜力。我们还分析了多元回归是否较单一因子回归表现出较高的预测能力,并提出了从每一种单根主要肢骨测量的颅后形态变量得到的最好代数函数