Testing sexual segregation and aggregation: old ways are best.

The study of sexual segregation has received increasing attention over the last two decades. Several hypotheses have been proposed to explain the existence of sexual segregation, such as the "predation risk hypothesis," the "forage selection hypothesis," and the "activity budget hypothesis." Testing which hypothesis drives sexual segregation is hampered, however, by the lack of consensus regarding a formal measurement of sexual segregation.

Testing for phylogenetic signal in phenotypic traits: new matrices of phylogenetic proximities.

Abouheif adapted a test for serial independence to detect a phylogenetic signal in phenotypic traits. We provide the exact analytic value of this test, revealing that it uses Moran's I statistic with a new matrix of phylogenetic proximities. We introduce then two new matrices of phylogenetic proximities highlighting their mathematical properties: matrix A which is used in Abouheif test and matrix M which is related to A and biodiversity studies.

A new technique for ordering asymmetrical three-dimensional data sets in ecology.

The aim of this paper is to tackle the problem that arises from asymmetrical data cubes formed by two crossed factors fixed by the experimenter (factor A and factor B, e.g., sites and dates) and a factor which is not controlled for (the species).

From dissimilarities among species to dissimilarities among communities: a double principal coordinate analysis.

This paper presents a new ordination method to compare several communities containing species that differ according to their taxonomic, morphological or biological features. The objective is first to find dissimilarities among communities from the knowledge about differences among their species, and second to describe these dissimilarities with regard to the feature diversity within communities. In 1986, Rao initiated a general framework for analysing the extent of the diversity.

Spatial variation in springtime food resources influences the winter body mass of roe deer fawns.

It is well established that the dynamics of mammalian populations vary in time, in relation to density and weather, and often in interaction with phenotypic differences (sex, age and social status). Habitat quality has recently been identified as another significant source of individual variability in vital rates of deer, including roe deer where spatial variations in fawn body mass were found to be only about a tenth of temporal variations. The approach used was to classify the habitat into blocks a priori, and to analyse variation in animal performance among the predefined areas.

Internal correspondence analysis of codon and amino-acid usage in thermophilic bacteria.

Starting from two datasets of codon usage in coding sequences from mesophilic and thermophilic bacteria, we used internal correspondence analysis to study the variability of codon usage within and between species, and within and between amino acids. The first dataset included 18,958,458 codons from 58,482 coding sequences from completely sequenced genomes of 25 species, along with 6,793,581 dinucleotides from 21,876 intergenic spaces. The second dataset, with partially sequenced genomes, included 97,095,873 codons from 293 bacterial species.