Molecular and immunogenetic analysis of major histocompatibility haplotypes in northern bobwhite enable direct identification of corresponding haplotypes in an endangered subspecies,the masked bobwhite

The major histocompatibility complex (MHC) is a group of genetic loci coding for haplotypes that have been associated with fitness traits in mammals and birds. Such associations suggest that MHC diversity may be an indicator of overall genetic fitness of endangered or threatened species. The MHC haplotypes of a captive population of 12 families of northern bobwhites (Colinus virginianus) were identified using a combination of immunogenetic and molecular techniques. Alloantisera were produced within families of northern bobwhites and were then tested for differential agglutination of erythrocytes of all members of each family. The pattern of reactions determined from testing these alloantisera identified a single genetic system of alloantigens in the northern bobwhites, resulting in the assignment of a tentative genotype to each individual within the quail families. Restriction fragment patterns of the DNA of each bird were determined using the chicken MHC B‐G cDNA probe bg11. The concordance between the restriction fragment patterns and the alloantisera reactions showed that the alloantisera had identified the MHC of the northern bobwhite and supported the tentative genotype assignments, identifying at least 12 northern bobwhite MHC haplotypes. Eighteen northern bobwhite alloantisera were then used to detect a minimum of 17 masked bobwhite MHC haplotypes. Subsequent restriction fragment pattern analyses using cDNA probes for chicken MHC genes were in agreement with agglutination patterns displayed by the antisera, showing that the immunogenetically identified alloantigen system constituted the MHC of the masked bobwhite. These data demonstrate that a non‐endangered species may be used to provide antisera for differentiating MHC haplotypes in a closely related endangered species, thus providing a practical basis for long‐range monitoring of MHC haplotypes of birds surviving in their native habitats. Zoo Biol 18:279–294, 1999. © 1999 Wiley‐Liss, Inc.     

Use of behavioral measures to assess reproductive status in maned wolves (Chrysocyon brachyurus)

Captive breeding efforts of the threatened maned wolf (Chrysocyon brachyurus) have been plagued by a lack of reliable reproduction and a high rate of neonatal mortality. A particular problem for animal managers has been the ability to detect pregnancy in a noninvasive manner. Pseudopregnancies are common, and many staff hours are expended preparing for a birth that may not occur. The objectives of our study were to document changes in behavior during the breeding season in captive maned wolves in order to determine if behaviors other than sexual (i.e., copulation) could be used to distinguish nonbreeding from breeding pairs and, further, whether successful breeding pairs (young born) could be distinguished behaviorally from breeding pairs that did not produce young (pseudopregnant). Between 1988 and 1994, behavioral data were collected during the annual reproductive season from 52 maned wolf pairings (27 males, 26 females) housed at 17 North American institutions. Breeding animals showed significant increases in rates of affiliative behaviors (approach, friendly) and the amount of time spent in close association (social) during the estrous period, compared to pre- and post-estrous periods. In contrast, the behavior of nonbreeding pairs varied little throughout the breeding season. Discriminant function analysis (DFA) showed that several behavioral measurements during certain reproductive periods were useful in discriminating between nonbreeding and breeding animals (rates of friendly and social behavior for males, marking and social behavior for females). Unsuccessful (pseudopregnant) and successful breeding pairs could be further distinguished on the basis of agonistic and approach behavior frequencies (successful females showed higher rates of agonistic and lower rates of approach behavior during certain periods; successful males had higher rates of both behaviors). Discriminant equations for key behavioral measurements and examples of their practical application are presented. DFA provides animal managers with an effective, noninvasive technique for assessing the reproductive status of maned wolf pairs. © 1996 Wiley-Liss, Inc.     

Genome‐scale data reveal that endemic Poecilia populations from small sulphidic springs display no evidence of inbreeding

Populations with limited ranges can be highly vulnerable to changes in their environment and are, thus, of high conservation concern. Populations that experience human‐induced range reductions are often highly inbred and lack genetic diversity, but it is unknown whether this is also the case for populations with naturally small ranges. The fishes Poecilia sulphuraria (listed as critically endangered) and Poecilia thermalis, which are endemic to small hydrogen sulphide‐rich springs in southern Mexico, are examples of such populations with inherently small habitats. We used geometric morphometrics and population genetics to quantify phenotypic and genetic variation within and among two populations of P. sulphuraria and one population of P. thermalis. Principal component analyses revealed phenotypic and genetic differences among the populations. Evidence for inbreeding was low compared to populations that have undergone habitat reduction. The genetic data were also used to infer the demographic history of these populations to obtain estimates for effective population sizes and migration rates. Effective population sizes were large given the small habitats of these populations. Our results imply that these three endemic extremophile populations should each be considered separately for conservation purposes. Additionally, this study suggests that populations in naturally small habitats may have lower rates of inbreeding and higher genetic diversity than expected, and therefore may be better equipped to handle environmental perturbations than anticipated. We caution, however, that the inferred lack of inbreeding and the large effective population sizes could potentially be a result of colonization by genetically diverse ancestors.     

Variation in Reproductive Success Across Captive Populations: Methodological Differences,Potential Biases and Opportunities

Our understanding of fundamental organismal biology has been disproportionately influenced by studies of a relatively small number of ‘model’ species extensively studied in captivity. Laboratory populations of model species are commonly subject to a number of forms of past and current selection that may affect experimental outcomes. Here, we examine these processes and their outcomes in one of the most widely used vertebrate species in the laboratory – the zebra finch (Taeniopygia guttata). This important model species is used for research across a broad range of fields, partly due to the ease with which it can be bred in captivity. However despite this perceived amenability, we demonstrate extensive variation in the success with which different laboratories and studies bred their subjects, and overall only 64% of all females that were given the opportunity, bred successfully in the laboratory. We identify and review several environmental, husbandry, life‐history and behavioural factors that potentially contribute to this variation. The variation in reproductive success across individuals could lead to biases in experimental outcomes and drive some of the heterogeneity in research outcomes across studies. The zebra finch remains an excellent captive animal system and our aim is to sharpen the insight that future studies of this species can provide, both to our understanding of this species and also with respect to the reproduction of captive animals more widely. We hope to improve systematic reporting methods and that further investigation of the issues we raise will lead both to advances in our fundamental understanding of avian reproduction as well as to improvements in future welfare and experimental efficiency.     

Reproductive strategy,spawning induction,spawning temperatures and early life history of captive sicklefin chub Macrhybopsis meeki

Macrhybopsis reproduction and propagule traits were studied in the laboratory using two temperature regimes and three hormone treatments to determine which methods produced the most spawns. Only sicklefin chub Macrhybopsis meeki spawned successfully although sturgeon chub Macrhybopsis gelida released unfertilized eggs. All temperature and hormone treatments produced M. meeki spawns, but two treatments had similar success rates at 44 and 43%, consisting of a constant daily temperature with no hormone added, or daily temperature fluctuations with hormone added to the water. Spawns consisted of multiple successful demersal circular swimming spawning embraces interspersed with circular swims without embraces. The most spawns observed for one female was four and on average, 327 eggs were collected after each spawn. The water‐hardened eggs were semi‐buoyant and non‐adhesive, the first confirmation of this type of reproductive guild in the Missouri River Macrhybopsis sp. From spawn, larvae swam vertically until 123 accumulated degree days (° D) and 167° D for consumption of first food. Using average water speed and laboratory development time, the predicted drift distance for eggs and larvae could be 468–592 km in the lower Missouri River. Results from this study determined the reproductive biology and early life history of Macrhybopsis spp. and provided insight into their population dynamics in the Missouri River.     

Age structure changes and extraordinary lifespan in wild medfly populations

The main purpose of this study was to test the hypotheses that major changes in age structure occur in wild populations of the Mediterranean fruit fly (medfly) and that a substantial fraction of individuals survive to middle age and beyond (> 3-4 weeks). We thus brought reference life tables and deconvolution models to bear on medfly mortality data gathered from a 3-year study of field-captured individuals that were monitored in the laboratory. The average time-to-death of captured females differed between sampling dates by 23.9, 22.7, and 37.0 days in the 2003, 2004, and 2005 field seasons, respectively. These shifts in average times-to-death provided evidence of changes in population age structure. Estimates indicated that middle-aged medflies (> 30 days) were common in the population. A surprise in the study was the extraordinary longevity observed in field-captured medflies. For example, 19 captured females but no reference females survived in the laboratory for 140 days or more, and 6 captured but no reference males survived in the laboratory for 170 days or more. This paper advances the study of aging in the wild by introducing a new method for estimating age structure in insect populations, demonstrating that major changes in age structure occur in field populations of insects, showing that middle-aged individuals are common in the wild, and revealing the extraordinary lifespans of wild-caught individuals due to their early life experience in the field.     

圈养条件下狍繁殖行为的研究

本试验研究了狍(东北亚种)在人工饲养条件下的繁殖行为。研究结果表明:(1)在交配季节,雄狍具有卷唇嗅闻、扒土等行为;雄狍与雌狍的卧息、冲突行为差异显著,尾阴探究差异极显著。(2)妊娠雌狍选择隐蔽处分娩产仔。(3)在临产前,雌狍有临产表现,采取侧卧分娩姿势,仔狍娩出后,舔食仔狍的胎水和胎膜。     

Phylogenetic analysis of the composition of bacterial communities in human-exploited coastal environments from Mallorca Island (Spain)

The phylogenetic analysis of bacterial communities in environments receiving anthropogenic impact could help us to understand its effects and might be useful in the development of monitoring or management strategies. A study of the composition of 16S rDNA clone libraries prepared from bacterial communities in water samples from a marina and a beach on the coast of Mallorca (W. Mediterranean) was undertaken at two time points, corresponding to periods of maximum and minimum anthropogenic use of this area for nautical and recreational activities. Libraries generated from the marina were significantly different from those from the beach and a non-impacted, bay sample. In the marina, a predominance of sequence types was observed related to bacterioplankton from nutrient-enriched environments or typically associated with phytoplankton, such as certain phylotypes of the Roseobacter clade, OM60 clade and Bacteroidetes. Similar results were found in the summer beach library but not in the winter one, in which there was an increase in the number of clones from oligotrophic groups, in agreement with lower chlorophyll content and bacterial counts. Therefore, nutrient enrichment seemed to be an important driver of the composition of bacterial communities in sites receiving direct human impact. Interesting sequence types from the Cryomorphaceae and group agg58 (Bacteroidetes) were exclusively found in beach libraries, and the reasons for this distribution deserve further study. Clones related to putative hydrocarbon-degrading bacteria of the genus Acinetobacter were observed in the marina, in agreement with a certain degree of pollution at this site. Non-marine sequences belonging to the Actinobacteria predominated over marine groups in the summer library from the marina and, therefore, unusual communities might be transiently present in this enclosed environment. Overall, the composition of the bacterial communities in these environments agreed well with the defining characteristics of the environments sampled.     

Genotypic variation in seedling root architectural traits and implications for drought adaptation in wheat (Triticum aestivum L.)

Root system characteristics are of fundamental importance to soil exploration and below-ground resource acquisition. Root architectural traits determine the in situ space-filling properties of a root system or root architecture. The growth angle of root axes is a principal component of root system architecture that has been strongly associated with acquisition efficiency in many crop species. The aims of this study were to examine the extent of genotypic variability for the growth angle and number of seminal roots in 27 current Australian and 3 CIMMYT wheat (Triticum aestivum L.) genotypes, and to quantify using fractal analysis the root system architecture of a subset of wheat genotypes contrasting in drought tolerance and seminal root characteristics. The growth angle and number of seminal roots showed significant genotypic variation among the wheat genotypes with values ranging from 36 to 56 (degrees) and 3 to 5 (plant⁻¹), respectively. Cluster analysis of wheat genotypes based on similarity in their seminal root characteristics resulted in four groups. The group composition reflected to some extent the genetic background and environmental adaptation of genotypes. Wheat cultivars grown widely in the Mediterranean environments of southern and western Australia generally had wider growth angle and lower number of seminal axes. In contrast, cultivars with superior performance on deep clay soils in the northern cropping region, such as SeriM82, Baxter, Babax, and Dharwar Dry exhibited a narrower angle of seminal axes. The wheat genotypes also showed significant variation in fractal dimension (D). The D values calculated for the individual segments of each root system suggested that, compared to the standard cultivar Hartog, the drought-tolerant genotypes adapted to the northern region tended to distribute relatively more roots in the soil volume directly underneath the plant. These findings suggest that wheat root system architecture is closely linked to the angle of seminal root axes at the seedling stage. The implications of genotypic variation in the seminal root characteristics and fractal dimension for specific adaptation to drought environment types are discussed with emphasis on the possible exploitation of root architectural traits in breeding for improved wheat cultivars for water-limited environments.     

Validation of the Macrophyte Quality Index (MaQI) set up to assess the ecological status of Italian marine transitional environments

The paper couples the results obtained by applying the expert and the rapid Macrophyte Quality Indices set up to assess the ecological status of the Italian transitional environments according to the requirements by the Water Framework Directive (2000/60/CE). The indices were validated by comparing the composition of the macrophyte assemblages and the values of some bio-physico-chemical parameters of the water column of 20 stations of the Venice lagoon sampled monthly for one year between 2003 and 2005. In 5 stations out of the 20, the ones which fall within the 5 classes of ecological status suggested by the Water Framework Directive, sedimentation rates, sediment grain-size, and nutrient and pollutant (metals, Polychloro-Dibenzo-Dioxins/Furans, Polycyclic Aromatic Hydrocarbons, Pesticides and Polychlorinated Biphenils) concentrations in surface sediments were also determined. Results showed strong relationships between the trends of these environmental parameters and the composition and structure of macrophyte associations, as well as with the Macrophyte Quality Index assessment. Chlorophyceae showed a trend opposite to Rhodophyceae whose presence was concentrated in oxygenated and transparent environments. Chlorophyceae and the species characterised by low scores prevailed in turbid areas where nutrient and pollutant concentrations were high. Results allowed the identification of the conditions of the “reference sites” (confinement areas and sites with high water renewal) and the integration of the dichotomic key used for the application of the R-MaQI. Handling editor: S. M. Thomaz