Extra-pair paternity in the strongly monogamous Wandering Albatross Diomedea exulans has no apparent benefits for females

Although 92% of avian species are socially monogamous, extra-pair copulation (EPC), resulting in extra-pair paternity (EPP), is a common reproductive strategy in birds. Among seabirds, in which the rate of social monogamy reaches 100%, Procellariiformes (albatrosses and petrels) show low EPP rates, with the noticeable exception of the only albatross investigated in this regard, the Waved Albatross Phoebastria irrorata . This species, in which forced copulations are known to occur, showed a surprisingly high rate of EPP (25% of chicks). We investigate here EPP rates in another albatross species, the Wandering Albatross Diomedea exulans , subject to a demographic survey conducted for 38 years. We combined data on pair bonds with analysis of ten microsatellite loci and found that 10.7% of 75 chicks had an extra-pair sire. Although there was some evidence for inbreeding avoidance, within-pair and extra-pair chicks showed similar levels of heterozygosity, and the incidence of EPP was independent of age, experience or past reproductive success. Hence, we found no evidence that females benefit from EPCs. Owing to the male-biased sex ratio in adults, widowed and divorced males required more time to find a new mate (+28 and +72%, respectively) than did females. Combined with high sexual size dimorphism, this phenomenon might promote the forced copulations observed in this species. Our data therefore suggest that EPC is beneficial to unpaired males but occurs at random in females, consistent with the hypothesis that EPP results solely from forced EPCs. However, the importance of the latter for EPP and the part played by solitary males require further investigation.     

Highly polytypic taxon complex: interspecific and intraspecific integrative taxonomic assessment of the widespread pollinator Bombus pascuorum Scopoli 1763 (Hymenoptera: Apidae)

The recent development of the integrative taxonomic approach in bumblebees has led to unexpected merging or splitting of several taxa. Here we investigate the taxonomic statuses of one of the most abundant, widespread and polytypic Palearctic bumblebees, Bombus pascuorum. The latest review of this species includes 24 subspecies. We used an integrative approach based on genetic markers and male chemical reproductive traits and compared our results with the former classifications. Our results show that all B. pascuorum taxa are conspecific and share the same male chemical reproductive traits. The genetic structure observed in one mitochondrial and two nuclear markers poorly reflects the current subspecific classification. Indeed, the concordance of population genetic differentiation, population geographic distribution, and population colour pattern similarity suggests a different meaningful prospective classification with four taxon complexes: (i) the B. pascuorum dusmeti group, including all taxa from the Iberian Peninsula and south‐west France; (ii) B. pascuorum rehbinderi; (iii) B. pascuorum siciliensis; and (iv) B. pascuorum floralis groups (including all other taxa studied here).     

Does Aconitum septentrionale chemically protect floral rewards to the advantage of specialist bumblebees?

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Large Genetic Heterogeneity Within Amoebas of the Species Naegleria gruberi and Evolutionary Affinities to the Other Species of the Genus

The allozyme survey was extended to 7 strains of Naegleria gruberi and N. jadini in order to further characterize the genetic structure of these free-living amoebas. As formerly known for several characters the electrophoretic evidence reveals considerable heterogeneity at the genetic level among N. gruberi strains. Moreover, 2 distinct gene pools, that might likely represent natural taxa, are clearly identified. The single strain of N. jadini appears evolutionarily related to 1 group of N. gruberi which is also related to N. a. australiensis.     

Discongruence of Mhc and cytochrome b phylogeographical patterns in Myodes glareolus (Rodentia: Cricetidae)

In the present study, a phylogeographical approach was developed to analyse the influence of selection and history on a major histocompatibility complex (Mhc) class II gene polymorphism in European bank vole (Myodes glareolus) populations. We focused on exon 2 of the Dqa gene because it is highly variable in a large array of species and appears to evolve under pathogen‐mediated selection in several rodent species. Using single‐strand conformation polymorphism analysis and sequencing techniques, 17 Dqa‐exon2 alleles, belonging to at least two different copies of Dqa gene, were detected over the distribution range of M. glareolus. Evidence of selection was found using molecular and population analyses. At the molecular level, we detected 13 codons evolving under positive selection pressures, most of them corresponding to regions coding for putative antigen binding sites of the protein. At the European level, we compared patterns of population structure for the Dqa‐exon2 and cytochrome b (cyt b) gene. We did not detect any spatial genetic structure among M. glareolus populations for the Dqa‐exon2. These results strongly differed from those obtained using the cyt b gene, which indicated a recent phylogeographical history closely linked to the last glacial events. Seven mitochondrial lineages have yet been described, which correspond to major glacial refugia. Altogether, our results revealed clear evidence of balancing selection acting on Dqa‐exon2 and maintaining polymorphism over large geographical areas despite M. glareolus history. It is thus likely that Mhc phylogeographical variability could have been shaped by local adaptation to pathogens. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105 , 881–899.     

A Comparative Study of 14 Strains of Naegleria australiensis Demonstrates the Existence of a Highly Virulent Subspecies: N. australiensis italica n. spp.1

Fourteen strains of Naegleria australiensis, including the type strain, were compared for virulence for mice, maximum growth temperature, lectin agglutination, isoenzyme pattern, and total protein banding pattern. Their relation to other species of Naegleria also was compared by immunoelectrophoretic analysis. Strains with high virulence, comparable to that of N. fowleri, were found to be different in concanavalin A agglutination as well as with regard to zymograms and total protein patterns. Although serologically different from N. fowleri and reacting with N. australiensis antiserum in the fluorescent antibody test, these high-virulence strains differed in number of immunoelectrophoretic precipitin bands. Because of these results, the high-virulence strains are considered to be a subspecies of N. australiensis. The low-virulence strains showed minor differences from the type strain. Thus, N. australiensis does not appear to be as homogenous a species as N. fowleri. Pathogenic N. australiensis also seems to be more widespread than previously thought.     

Inclusive Fitness and Human Family Structure

The implications of sociobiology, and especially of "inclusive fitness" or "kin-selection" theory, to human family structures are explored. Kin-selection theory provides a model to formulate testable hypotheses predicting cooperation and conflict for categories of kinsmen; it also suggests an alternative way of looking at incest, endogamy, exogamy, rule of descent, and type of marriage in terms of such biological concepts as mating strategies, inclusive fitness, parental investment, and sexual dimorphism and bimaturism. [sociobiology, kin-selection theory, inclusive fitness, family structure, marriage]