A multivariate and cladistic study of Vicia L. ser. Vicia (Fabaceae) based on analysis of morphological characters

 Vicia ser. Vicia, which includes the Vicia sativa aggregate, was studied by observing morphological variation. The study is an attempt to resolve the taxonomic relationships within the Vicia sativa aggregate by novel investigations along with a synthesis of the results obtained by previous researchers. The study has included some accessions and characters used previously, but has drawn accessions from a wider geographical range than has been attempted previously. Cluster analysis on the basis of 53 morphological characters justified the delimitation of four species within the series and six subspecies within the Vicia sativa aggregate. Accessions from South Asia could easily be incorporated in the classification, but some of the accessions from North Africa showed morphological differences. The morphometric data were coded using the gap weighting method of Thiele (1993) and used in a phylogenetic analysis to study the relationships between the taxa. The phylogenetic analysis, using 33 variables, showed Vicia pyrenaica closely related to Vicia sativa subsp. amphicarpa. A dichotomous key and a multi-access key to aid the identification of the taxa in the series are presented. Received January 21, 2002; accepted November 8, 2002 Published online: March 20, 2003     

Measuring the structural similarity of two communities composed of the same species

Summary The primary purpose of this paper is to propose empirical measures of the structural differences between two communities of plants or animals composed of the same species. Structure is defined to consist of; 1) the species in the community, 2) the pattern of interactions as represented by the covariance or correlation matrix of successive observations on each species, and 3) the mean abundances of each species in each of the two communities. Statistical tests are proposed for testing whether the covariance matrices and the vectors of mean densities for each community are equal and empirical measures of the differences between the covariance matrices and mean vectors are proposed. Given unequal covariance or correlation matrices the factor analysis model is used to derive empirical measures of the degree to which each variable of the ecosystem is responsible for the observed defferences in the pattern of interactions in each community. These tests and measures were applied to data gathered byHunter (1966) on the abundances of six species ofDrosophila censused monthly over a period of approximately two and a half years in two adjacent, but different habitats near Bogota, colombia. The two covariance matrices were significantly different indicating different patterns of interactions in the twoDrosophila communities.     

Fragmentation causes rarity in common marmosets in the Atlantic forest of northeastern Brazil

The purpose of this study was to investigate the population status of the common marmosets, Callithrix jacchus, in one of their main habitats, the northeastern Atlantic forest of Brazil, where only 2% of its original area remains as small and isolated forest fragments, to determine long-term viable populations. The study was carried out in 15 forest fragments, measuring from 3,478.3 ha (the largest) to 6 ha, which were invariably subjected to high human impact. Line transect surveys were carried out between January 2002 and December 2004, along transects measuring from 350 to 4,000 m, between 0500 h and 0900 h. Common marmosets were registered in 73% (n = 11) of the forest fragments, were not recorded in the largest one, the Coimbra Forest, and group sizes varied from 1 to 4 individuals. A negative significant relationship was detected between the size of the fragment and the number of sightings of common marmosets. It is shown that the number of groups of common marmosets dwelling in this highly impacted landscape is nowadays lower than necessary for long-term survival. Additionally, smaller fragments having more groups suggests that they live in total association with humans, which assure their subsistence through the supply of introduced and exotic foods.     

Changes in the food of British Barn Owls (Tyto alba) between 1974 and 1997

Comparison of the results of a 1993–97 Barn Owl Tyto alba pellet survey with those of a similar survey from 1956–74 showed that Barn Owl diet had changed significantly. The primary differences were a widespread decrease in the percentage of Common Shrew Sorex araneus, combined with an increase in Pygmy Shrew Sorex minutus. The percentage of Wood and Yellow‐necked mice Apodemus sylvaticus and A. flavicollis and Bank Vole Clethrionomys glareolus in the diet also increased. Changes in Barn Owl diet since 1974 were independent of land‐class group, but were dependent upon region. This was due primarily to a large increase in the percentage of Apodemus spp. in Eastern England. Whilst the percentage of Pygmy Shrew in Barn Owl diet showed significant regional variation, there was no significant variation between land‐class groups. The diversity of Barn Owl diet increased between 1974 and 1997, although it was still lower in 1997 than earlier in the century. This increase was dependent upon region, but independent of land‐class group. The combined results of both surveys showed significant interland‐class group variation in dietary diversity. Changes in diet are discussed in relation to the intensification of agriculture and other changes in land management since the 1970s. The effects on Barn Owls of these changes in prey abundance are discussed, particularly in relation to the decline in Barn Owl numbers during the twentieth century.     

The genomics of selenium: Its past,present and future

In the last two decades, genomic analyses have enriched the study of the biology of selenium in many ways. These include the identification of selenoproteins in prokaryotic and eukaryotic genomes, the discovery of genetic variants that mediate humans and other vertebrates' adaptations to their selenium nutritional histories, and the association of specific genotypes with common and rare human selenium disorders. We briefly review these computational, evolutionary and association studies and their contribution to the genomics of selenium, selenocysteine and selenoproteins in the 200th anniversary of the discovery of this trace element.     

普通小麦—天蓝冰草部分双二倍体基因组变异的研究

根据传统理论，在禾本科特别是含有多倍体小麦为亲本的禾本科结合，稳定的双二倍体中应存在极少的基因组变异，然而，利用１０个小麦低拷贝染色体专化序列和３３个具代表性同源群专化序列为探针，对２个普通小麦（ＴｒｉｔｉｃｕｍａｅｓｔｉｖｕｍＬ．）－天蓝冰草（Ａｇｒｏｐｙｒｏｎｉｎｔｅｒｍｅｄｉｕｍ（Ｈｏｓｔ）Ｐ．Ｂ＝Ｅｌｙｔｒｉｇｉａｉｎｔｅｍｅｄｉａ（Ｈｏｓｔ）Ｎｅｖｓｋｉ＝Ｔｈｉｎｏｐｙｒｕｍｉｎｔｅｒｍ     

Seasonal and diurnal patterns of population vocal activity in avian brood parasites

Patterns of vocal activity may involve information about vocalizations themselves as well as their function. In birds, vocal activity at the individual and population level is generally closely associated with breeding cycles, reaching the peak during territorial and mating competition, and decreasing with the onset of egg incubation and chick feeding. However, little is known about patterns of vocal activity in avian brood parasites that have unusual breeding cycles without parental care. Using passive acoustic monitoring, we determined the seasonal and diurnal patterns of population vocal activity in two avian brood parasites: the Common Cuckoo Cuculus canorus and the Lesser Cuckoo C. poliocephalus. We found that both species and both sexes showed a similarly highly structured pattern of seasonal vocal activity, reaching a sharp peak in the early breeding season when birds compete for territories and mates, although males sang more frequently than females. Likewise, the diurnal patterns of vocal activity were similar in both species and both sexes of cuckoos, with peak activity occurring around dawn. Nocturnal calls by male cuckoos were also detected in both species, but only in the early breeding season. Collectively, the observed patterns of population vocal activity may suggest that the absence of parental care may not extend the period of vocal activity in these two species of brood parasites.     

Individual condition,but not fledging phenology,carries over to affect post-fledging survival in a Neotropical migratory songbird

Migratory animals face severe time and energy constraints during their annual cycle. These constraints may be exacerbated in young animals by conditions experienced during development that can affect both phenotype and phenology. For young migratory songbirds, the period between fledging and autumn migration, the post-fledging period, is believed to represent a time of intense selective pressure. However, there has yet to be a study that has assessed post-fledging survival for the entirety of the post-fledging period, probably due to the challenge of following juveniles as they move broadly across the landscape (tens to hundreds of kilometres). To overcome this challenge, we used an automated radiotelemetry array spanning 60 000 km² in southern Ontario, Canada, and miniature digital radiotelemetry tags to track 216 juvenile Barn Swallows Hirundo rustica continuously from fledging to migration. We hypothesized that young that fledged in better condition and earlier in the breeding season would have higher survival relative to birds fledging in poorer condition, because they have more energy to deal with resource constraints, and that early-fledging birds would depart on migration earlier than late-fledging birds because there is probably a fixed period of time required post-fledging to prepare for migration. We found that average cumulative apparent survival was 42% and that condition in the nest was a strong positive predictor of post-fledging apparent survival. We also found that birds that fledged earlier in the season departed on migration earlier in the autumn relative to late-fledging birds. Contrary to our prediction, average apparent survival was equal for early- and late-fledging birds. Our results suggest that factors during development that promote better nestling condition are critical for predicting future apparent survival prior to migration. Differences in annual apparent survival between early- and late-fledging songbirds, as commonly observed, may be driven by events occurring at later stages of the annual cycle.     

Deciphering genetic basis of developmental and agronomic traits by integrating high-throughput optical phenotyping and genome-wide association studies in wheat

Dissecting the genetic basis of complex traits such as dynamic growth and yield potential is a major challenge in crops. Monitoring the growth throughout growing season in a large wheat population to uncover the temporal genetic controls for plant growth and yield-related traits has so far not been explored. In this study, a diverse wheat panel composed of 288 lines was monitored by a non-invasive and high-throughput phenotyping platform to collect growth traits from seedling to grain filling stage and their relationship with yield-related traits was further explored. Whole genome re-sequencing of the panel provided 12.64 million markers for a high-resolution genome-wide association analysis using 190 image-based traits and 17 agronomic traits. A total of 8327 marker-trait associations were detected and clustered into 1605 quantitative trait loci (QTLs) including a number of known genes or QTLs. We identified 277 pleiotropic QTLs controlling multiple traits at different growth stages which revealed temporal dynamics of QTLs action on plant development and yield production in wheat. A candidate gene related to plant growth that was detected by image traits was further validated. Particularly, our study demonstrated that the yield-related traits are largely predictable using models developed based on i-traits and provide possibility for high-throughput early selection, thus to accelerate breeding process. Our study explored the genetic architecture of growth and yield-related traits by combining high-throughput phenotyping and genotyping, which further unravelled the complex and stage-specific contributions of genetic loci to optimize growth and yield in wheat.