Fine-scale genetic structuring in a natural population of European wild rabbits (Oryctolagus cuniculus)

The genetic structure of a free-living tagged population of European wild rabbits (Oryctolagus cuniculus) was investigated for two consecutive years (1990 and 1991) using 10 polymorphic microsatellite loci. A specific social behaviour, the formation of stable breeding groups, influenced the genetic structure of the population. These breeding groups were shown to constitute genetically differentiated units with low levels of gene flow between them. The average relatedness among members of a social group was higher than within the population as a whole. As a result of female philopatry coupled with male-biased natal dispersal, the relatedness of females was higher than that of males, both within social groups and in the whole population. Furthermore, the average relatedness of females within groups was twice the relatedness of females between groups. This study reveals marked fine-scale, intrapopulation genetic structure, which is attributable to the social behaviour of the European wild rabbit.     

Natal dispersal and genetic structure in a population of the European wild rabbit (Oryctolagus cuniculus)

A combination of behavioural observation, DNA fingerprinting, and allozyme analysis were used to examine natal dispersal in a wild rabbit population. Rabbits lived in territorial, warren based social groups. Over a 6-year period, significantly more male than female rabbits moved to a new social group before the start of their first breeding season. This pattern of female philopatry and male dispersal was reflected in the genetic structure of the population. DNA fingerprint band-sharing coefficients were significantly higher for females within the same group than for females between groups, while this was not the case for males. Wrighfs inbreeding coefficients were calculated from fingerprint band-sharing values and compared to those obtained from allozyme data. There was little correlation between the relative magnitudes of the F-statistics calculated using the two techniques for comparisons between different social groups. In contrast, two alternative methods for calculating F_ST from DNA fingerprints gave reasonably concordant values although those based on band-sharing were consistently lower than those calculated by an ‘allele’ frequency approach. A negative F_IS value was obtained from allozyme data. Such excess heterozygosity within social groups is expected even under random mating given the social structure and sex-biased dispersal but it is argued that the possibility of behavioural avoidance of inbreeding should not be discounted in this species. Estimates of genetic differentiation obtained from allozyme and DNA fingerprint data agreed closely with reported estimates for the yellow-bellied marmot, a species with a very similar social structure to the European rabbit.     

Origin of European rabbit (Oryctolagus cuniculus) in a Mediterranean island: Zooarchaeology and ancient DNA examination

Mammalian species presently living on Mediterranean islands have been brought in by man. The question of their geographical origin and of the time of their introduction is often a matter of debate. We studied this problem using a population of rabbits (European rabbit: Oryctolagus cuniculus) living in Zembra, an island off Tunisia. Archaeological surveys show that rabbit has been introduced to the island by Bronze Age or Roman people, between the IIIrd Millenium B.C. and the IIIrd century A.D. Part of the 16S-rRNA gene of mitochondrial DNAs from fossil bones of different ages (dated back to 130–390 A.D.) was characterized and compared to that of present day rabbits of differing geographical origin. The data suggest that animals present on Zembra in late Roman times belonged to the same maternal lineage as present populations from Northern Spain and Southern France.     

Exogenous and endogenous stages of Eimeria perforans naturally infected domestic rabbit (Oryctolagus cuniculus) in Saudi Arabia: Light microscopic study

Exogenous and endogenous stages of Eimeria perforans naturally infected rabbits in Saudi Arabia were described. The prevalence of infection was 75%. Oocysts were ovoid to elliptical and measured 16 × 10 μm. The four dizoic sporocysts were ovoid and measured 7 × 5 μm. Endogenous stages were restricted to the duodenum. Meronts, microgamonts, macrogamonts and young oocysts were recorded and described.     

From population structure to individual behaviour: genetic analysis of social structure in the European wild rabbit (Oryctolagus cuniculus)

The European wild rabbit (Oryctolagus cuniculus) lives in stable, territorial breeding groups, with male-biased natal dispersal, female philopatry, and a polygynous mating system. It was introduced into Britain in the 11 th century and kept in captive warrens as a food and fur resource. Populations expanded in the wild in the 18th century. Microsatellite markers were employed to examine the genetic structure of wild rabbit populations on three spatial scales: macrogeographic structure of 17 populations in East Anglia, microgeographic structure of a tagged population in the grounds of the University of East Anglia over four consecutive years, and pairwise kinships and individual movement within this tagged population. Populations across East Anglia were found to be genetically distinct, and heterozygote deficits were observed at all loci indicating sub-division within sampled populations. Analysis of the tagged population confirmed that rabbit populations are genetically sub-divided among social groups. Studying this population over four consecutive years revealed that as the population size increased, the number of social groups increased. Analysis of individual pairwise relatedness of females indicated that individuals did not necessarily group with kin, and behavioural data indicate that an optimum group size may exist which maximizes reproductive success.     

Formation of nutrient‐poor soil patches in a semi‐arid woodland by the European rabbit (Oryctolagus cuniculus L.)

Abstract European rabbits (Oryctolagus cuniculus L.) occur over large areas of eastern Australia, where they disturb significant quantities of soil while constructing warrens. Although the effects of rabbits on vegetation are generally well understood, little is known about their effects on soil physical or chemical properties. We studied the effect of rabbit warrens on soil chemistry in a semi‐arid woodland supporting a high density of rabbit warrens. Within one large warren, we examined nutrient concentrations within three microsites (mound, inter‐mound and an intermediate disturbed area) representing a gradient of increasing rabbit disturbance, and supported this with a study of soil nutrients with depth within 1‐m‐deep trenches through five warrens. Landscape‐level changes in surface chemistry were also examined at an additional 23 warrens. At both patch and landscape scales, pH, electrical conductivity, soluble and exchangeable Ca²⁺ and K⁺, and total Al and Ca generally increased with increasing rabbit disturbance, while total C and S (LECO), total P and S (ICP), and soluble Na⁺ declined, and total N remained unchanged. Although chemical changes with depth were generally ill defined, surface soils tended to be more similar in their composition than deeper soils. Overall, our results reinforced the view that rabbits have a negative effect on surface soils in semi‐arid woodlands, and suggested that restoration of the original woodland vegetation may be hampered by changes in soil biogeochemistry associated with the warrens.     

Absence of a genetic bottleneck in a wild rabbit (Oryctolagus cuniculus) population exposed to a severe viral epizootic

Infectious diseases and their demographic consequences are thought to influence the genetic diversity of populations. In Europe, during the last 50 years, the European rabbit (Oryctolagus cuniculus) has suffered two important viral epizootics: myxomatosis and rabbit viral haemorraghic disease (RVHD). Although mortality rates were very high, the impact of these diseases on genetic diversity has never been assessed directly. The subject of this paper is a wild rabbit population in France, which has been studied since the beginning of the 1980s. The first outbreak of RVHD occurred in 1995 and provoked a demographic crash. The population, sampled for the first time in 1982 and 1994, was sampled again at the end of 1996 to examine the impact of the epizootic on genetic diversity. In spite of the observed high mortality rate ( approximately 90%), analysis of 14 polymorphic loci (allozymes and microsatellites) showed no loss in genetic diversity after the epizootic. Determination of temporal changes in allele frequencies indicated that the population evolved under genetic drift. The temporal method of Waples demonstrated a significant decrease in the effective population size (Ne) correlated with the demographic crash due to the epizootic. However, the population had only been studied for two generations after the epizootic and the remnant population size probably stayed high enough ( approximately 50 individuals) to keep its genetic diversity at the precrash level. These results suggest that, contrary to what is usually thought and in spite of the subsequent high mortality rates, past epizootics (especially myxomatosis) may have had little effect on the genetic diversity of wild rabbit populations in Europe.     

Weak relationships of parasite infection with sexual and life‐history traits in wild‐caught Texas field crickets (Gryllus texensis)

1. Sex differences in immune investment and infection rate are predicted due to the divergent life histories of males and females, where females invest more toward immunity due to the fitness consequences of a reduced lifespan and males allocate less toward immunity due to increased resource investment in traits critical to sexual selection. Consequently, males are expected to fight infection less adeptly, resulting in higher parasite loads relative to females across all taxa.
2. Wild animals rarely face a single parasite within their given environment, yet nearly all studies on sex‐biased infection rates have focused on a single host–parasite relationship. Here, we investigate how simultaneous natural infections of ecto‐ and endosymbionts (i.e. both parasitic and phoretic taxa) correlate with sex biases in host immune response and reproductive investment in a field‐caught cricket, Gryllus texensis.
3. Our comprehensive analysis found no significant sex differences in two measures of immune response (melanization and nodulation), and found no strong evidence of a sex bias in the prevalence or intensity of parasitism by the three most common parasites infecting wild G. texensis field crickets (Eutrombidiidae, gregarines, and nematodes).
4. Two traits related to female fitness, egg number and egg size, showed no relation to parasitic infection; however, males having wider heads and poorer body condition were significantly more infected by eutrombidiid mites, gregarines, and nematodes.
5. Despite frequent predictions of male‐biased parasitism in the literature, our results concur with many other studies indicating that the divergent life histories of males and females alone are not sufficient to explain natural infection rates in wild insects.

     

Is the wild rabbit (<Emphasis Type="Italic">Oryctolagus cuniculus</Emphasis>) a threatened species in spain? Sociological constraints in the conservation of species

The Wild rabbit (Oryctolagus cuniculus) is an endemic species of the Iberian Peninsula and is essential for the conservation of endangered predators. Rabbits are also of high importance as a hunting species. From 1988, rabbits suffered the severe effects of rabbit hemorrhagic disease, which caused large declines in most populations. Despite this fact, the National Red Data Lists continued to classify rabbits as a “Least Concern” species. We used available hunting bag data from 1973 to 2002 to model national trends of rabbit abundance and to evaluate the conservation status according to the criteria of the National Red Data List and the World Conservation Union (IUCN). Generalized Additive Models were used as the statistical framework. The rabbit population of Spain suffered a large decline of about 71% between 1973 and 1993. This decline was 49% in the period 1980–1990. Based on both Spanish and World Conservation Union criteria, rabbits should be listed as ‘Vulnerable’, which demands a Conservation Plan Program. We suggest that the lack of concordance between the best available evidence and the conservation status of the species is a consequence of sociological constraints in conservation decisions. Rabbit conservation could face strong opposition from important socio-economic lobby groups (hunters and farmers). As such, governments and researchers may prefer to exclude rabbits from any status category requiring conservation action, despite the evidence of decline. We call for the urgent development of a nation-wide conservation program for rabbits which includes both socioeconomic constraints and the available biological data on population trends.     

Postglacial dispersal of the European rabbit (Oryctolagus cuniculus) on the Iberian peninsula reconstructed from nested clade and mismatch analyses of mitochondrial DNA genetic variation

Nested clade analysis was applied to cytochrome b restriction site data previously obtained on 20 natural populations of the European rabbit across the Iberian Peninsula to test the hypothesis of postglacial dispersal from two main refugia, one in the northeast and the other in the southwest. Apart from historical fragmentation that resulted in geographic discontinuity of two distinct mitochondrial DNA (mtDNA) clades A and B, patterns of haplotype genetic variability have been shaped mostly by restricted gene flow via isolation by distance. The distribution of tip versus interior haplotypes suggests that dispersal occurred from both the southwestern and northeastern groups. Dispersal from the southwest had a north and northwest direction, whereas from the northeast it had mostly a western and southern orientation, with subsequent overlap in a southeastern-northwestern axis across the Iberian Peninsula. The analysis of the pairwise mismatch distribution of a 179-181-bp fragment of the mtDNA control region, for seven of those populations, further supports the idea that major patterns of dispersal were in the direction of central Iberia. Additionally, rabbit populations do not show signs of any significant loss of genetic diversity in the recent past, implying that they maintained large population sizes and structure throughout the ice ages. This is congruent with the fact that the Iberian Peninsula was itself a glacial refugium during Quaternary ice ages. Nonetheless, climatic oscillations of this period, although certainly milder than in northern Europe, were sufficient to affect the range distributions of Iberian organisms.     

Feeding responses of the red fox (<Emphasis Type="Italic">Vulpes vulpes</Emphasis>) to different wild rabbit (<Emphasis Type="Italic">Oryctolagus cuniculus</Emphasis>) densities: a regional approach

We investigate the feeding responses of the red fox (Vulpes vulpes) at a regional scale to different densities of European wild rabbit (Oryctolagus cuniculus) in central–southern Spain. Rabbit abundance indices were obtained in 86 localities during summer 2002. The diet of the fox was studied by analysis of 114 scats collected in 47 of these localities. The feeding response of the fox was examined by a representation of the dry weight percent of rabbit in the diet as a function of the abundance of rabbits; this used data only from those localities where at least 3 scats were collected (70 fox scats from 18 localities). We evaluated the relationship between rabbit abundance and the diversity of the diet of the fox. The feeding patterns of red foxes approximated to Holling’s type III functional response, typical of opportunistic predators. There was a negative relationship between the diversity of the fox’s diet and the abundance of rabbits. Therefore, the fox apparently behaves as a facultative predator, feeding on rabbits when they are abundant and shifting to other prey (and hence a more diverse diet) when rabbits are scarce. These findings are the first step towards understanding the potential role of red foxes in regulating rabbit populations in central–southern Spain.     

Experimental infection of Eurasian collared‐dove (Streptopelia decaocto) with West Nile virus

The Eurasian collared‐dove (Streptopelia decaocto) has recently experienced a population explosion in North America. It is frequently infected with West Nile virus (WNV). To test the hypothesis that the Eurasian collared‐dove is competent to transmit WNV, we experimentally infected two cohorts of doves with two different strains of WNV, CO08, and NY99, respectively. Both virus strains induced a low‐level viremia, capable of infecting a small fraction of vector mosquitoes. We suggest that the Eurasian collared‐dove plays a relatively insignificant role as an amplifying host for WNV, but it may be important where it is locally abundant.     

Characterization of a prion protein (PrP) gene from rabbit; a species with apparent resistance to infection by prions

The prion protein gene (PrP) encodes a cellular protein of unknown function. A conformational isoform of this protein is involved in the neurodegenerative prion diseases. To facilitate the identification of structurally and antigenically important regions within the PrP molecule, the rabbit PrP open reading frame (ORF) was cloned and characterised. There is 82–87% identity at the nucleotide sequence level and 88–93% identity at the amino acid (aa) sequence level, between the rabbit gene and PrP sequences of other mammals. The rabbit gene shares structural and organisational features common to all known PrP genes signifying that it is the rabbit PrP gene. Comparison of the rabbit PrP aa sequence with PrP aa sequences from different species revealed several potential epitopes. Two anti-ovine PrP peptide Ab raised in rabbits, 168-92 and 98-92, confirmed that two separate cross-reacting epitopes segregate with single aa differences between rabbit and sheep PrP at positions 43 and 99 of the rabbit PrP polypeptide. The presence of these epitopes correlates with the species recognition patterns of previously published Ab. The usefulness of the rabbit PrP gene sequence in predicting antigenic regions within the PrP proteins of various species is illustrated. The structure of the rabbit PrP protein in relation to rabbits' apparent resistance to infection by prions is discussed.     

High production of poly(3‐hydroxybutyrate) from a wild Bacillus megaterium Bolivian strain

Aim

Taking into account that a novel strain of Bacillus megaterium was isolated from Uyuni salt lake (Bolivia) in a previous work, the objectives of this new study were to determine the maximal Poly‐3‐hydroxybutyrate production potential of B. megaterium strain uyuni S29 in an industrial conventional media, the possibility that the strain accumulates different types of polyhydroxyalkanoates, the cellular morphology during the biosynthesis process and the characterization of the produced biopolymers.

Methods and Results

The micro‐organism was first tested in a 3‐L bioreactor obtaining a high specific growth rate of 1·64 h^?1. A second fed‐batch experiment was carried out in shaking flasks, reaching up to 70% PHB of cell dry mass. The biosynthesized polymers were extracted by two different extraction procedures and characterized. The results showed that all of them were PHB with thermal properties different to the conventional PHB. The micrographs taken by TEM show the different cell morphology during the fermentation process.

Conclusions

In this previous study, the strain not only grew properly in the industrial conditions proposed without spore formation, but also produced and accumulated a large content of PHB, never reached before for its genus. Therefore, if the culture conditions can be optimized, the biopolymer production could be increased.

Significance and Impact of the Study

The impact of the study has related to the area of the biomaterials and their production. The study provides new data related to the high production of PHB from the wild novel strain B. megaterium uyuni S29, the highest polymer accumulation for the genus Bacillus without spores formation.     

Coulonia parva n. sp., a new species of Astropectinidae (Asteroidea; Echinodermata) from the Santonian (Upper Cretaceous) of Sierra de Montsech (southern Pyrenees, Spain)

A new astropectinid sea star,Coulonia parva n. sp., is described from the Santonian of the Sierra de Montsech, northern Spain. The single specimen shows part of a rather weathered ventral side. It is characterized by comparatively long arms (R/r approx. 3/1), with one row of actinals reaching far into the arms; inferomarginals on the interbrachial arc have deep fasciolar grooves that are less developed on the arms; there are no larger spines on adambulacrals and probably also on inferomarginals. Based on presence of deep marginal fascioles,C. parva n. sp. is inferred to have shared the capability for self-burial with the relatedC. platyspina Hess &Blake.      

Isolation and characterization of a manganese‐oxidizing bacterium from a biofiltration system for the treatment of borehole water in KwaZulu‐Natal (South Africa)

Using minimal salts medium containing vitamins and pyruvate (MSVP) plus added manganese sulfate, a manganese (II) oxidizing bacterial strain was isolated from water samples of a biofiltration system treating borehole water in KwaZulu‐Natal, South Africa. The nonmotile Gram‐negative and oxidase‐negative isolate was subsequently characterized microbiologically. Based on its morphological and physiological characteristics and on the analysis of its 16S rRNA gene sequence, the isolate was assigned to the genus Acinetobacter. Growth of the isolated strain in MSVP with added manganese sulfate gave rise to a drop in pH and a concomitant increase in oxidation–reduction potential, which was absent in controls, thus indicating manganese oxidation. The ability of Acinetobacter sp. strain LB1 to oxidize Mn (II) was further verified using the leucoberbelin blue dye assay as well as by energy dispersive X‐ray analysis of crystals formed in the medium. In addition, a biofilm assay indicated that this isolate can attach to solid surfaces such as a biofilter matrix, thus confirming its potential for biotechnological applications in the area of water purification.