| 1. |
- Arnqvist, Göran, et al.
(författare)
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Sex-role reversed nuptial feeding reduces male kleptoparasitism of females in Zeus bugs (Heteroptera : Veliidae)
- 2006
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Ingår i: Biology Letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 2:4, s. 491-493
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Tidskriftsartikel (refereegranskat)abstract
- Males of a variety of taxa occasionally steal food secured by their mates. In some spiders and insects, males rely entirely on this form of intraspecific kleptoparasitism for their subsistence. However, this male strategy may be costly for females and a variety of different female counteradaptations have been proposed. In Zeus bugs ( Phoreticovelia spp.), males ride on the back of their mates for extended periods and females produce a gland secretion that males feed on. By experimentally occluding the dorsal glands in females and varying food availability, we show that nuptial feeding by females reduces the extent to which the males kleptoparasitize their mates. We suggest that females have, at least in part, evolved this unique form of nuptial feeding as a counteradaptation to reduce the rate of kleptoparasitism by males.
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| 2. |
- Backström, Niclas, et al.
(författare)
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Levels of linkage disequilibrium in a wild bird population
- 2006
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Ingår i: Biology Letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 2:3, s. 435-438
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Tidskriftsartikel (refereegranskat)abstract
- Population-based mapping approaches are attractive for tracing the genetic background to phenotypic traits in wild species, given that it is often difficult to gather extensive and well-defined pedigrees needed for quantitative trait locus analysis. However, the feasibility of association or hitch-hiking mapping is dependent on the degree of linkage disequilibrium. (LD) in the population, on which there is yet limited information for wild species. Here we use single nucleotide polymorphism (SNP) markers from 23 genes in a recently established linkage map of the Z chromosome of the collared flycatcher, to study the extent of LD in a natural bird population. In most but not all cases we find SNPs within the same intron (less than 500 bp) to be in perfect LD. However, LD then decays to background level at a distance 1 cM or 400-500 kb. Although LD seems more extensive than in other species, if the observed pattern is representative for other regions of the genome and turns out to be a general feature of natural bird populations, dense marker maps might be needed for genome scans aimed at identifying association between marker and trait loci.
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| 3. |
- Bedhomme, Stephanie, et al.
(författare)
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How does breeding system variation modulate sexual antagonism?
- 2009
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Ingår i: Biology letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 5:5, s. 717-720
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The study of sexually antagonistic (SA) traits remains largely limited to dioecious (separate sex), mobile animals. However, the occurrence of sexual conflict is restricted neither by breeding system (the mode of sexual reproduction, e. g. dioecy or hermaphroditism) nor by sessility. Here, we synthesize how variation in breeding system can affect the evolution and expression of intra- and inter-locus sexual conflicts in plants and animals. We predict that, in hermaphrodites, SA traits will (i) display lower levels of polymorphism; (ii) respond more quickly to selection; and (iii) involve unique forms of interlocus conflict over sex allocation, mating roles and selfing rates. Explicit modelling and empirical tests in a broader range of breeding systems are necessary to obtain a general understanding of the evolution of SA traits.
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| 4. |
- Bracht Jörgensen, Helene, et al.
(författare)
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Selective foraging of fungi by collembolans in soil
- 2005
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Ingår i: Biology letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 1:2, s. 243-246
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Tidskriftsartikel (refereegranskat)abstract
- Soils contain highly diverse communities of microorganisms and invertebrates. The trophic interactions between these species are largely unknown. Collembolans form an abundant part of the invertebrate community in soils. A prevailing view is that soil collembolans are generalist feeders on fungi, lichens, fragmented litter and bacteria. However, in laboratory food choice experiments, it has been shown that collembolans preferentially select certain taxa of fungi. To examine this apparent contradiction, we developed a molecular technique based on the analysis of 18S ribosomal DNA (rDNA) sequences to explore the diversity of fungi in soils and in the guts of collembolans. We report that the diversity of fungi found in the natural soil was 33 times higher than that in the guts of the collembolan Protaphorura armata. The data support the view that collembolan species can be highly selective when foraging on fungi in soils.
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| 5. |
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| 6. |
- D'Hertefeldt, Tina, et al.
(författare)
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Long-term persistence of GM oilseed rape in the seedbank
- 2008
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Ingår i: Biology letters. - London : The Royal Society. - 1744-9561 .- 1744-957X. ; 4:3, s. 314-317
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Tidskriftsartikel (refereegranskat)abstract
- Coexistence between genetically modified (GM) and non-GM plants is a field of rapid development and considerable controversy. In crops, it is increasingly important to understand and predict the GM volunteer emergence in subsequent non-GM crops. Theoretical models suggest recruitment from the seedbank over extended periods, but empirical evidence matching these predictions has been scarce. Here, we provide evidence of long-term GM seed persistence in conventional agriculture. Ten years after a trial of GM herbicide-tolerant oilseed rape, emergent seedlings were collected and tested for herbicide tolerance. Seedlings that survived the glufosinate herbicide (15 out of 38 volunteers) tested positive for at least one GM insert. The resulting density was equivalent to 0.01 plants m−2, despite complying with volunteer reduction recommendations. These results are important in relation to debating and regulating coexistence of GM and non-GM crops, particularly for planting non-GM crops after GM crops in the same field.
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| 7. |
- Ericson, Per G P, 1956-, et al.
(författare)
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Diversification of Neoaves : integration of molecular sequence data and fossils.
- 2006
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Ingår i: Biology Letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 2:4, s. 543-7
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Tidskriftsartikel (refereegranskat)abstract
- Patterns of diversification and timing of evolution within Neoaves, which includes almost 95% of all bird species, are virtually unknown. On the other hand, molecular data consistently indicate a Cretaceous origin of many neoavian lineages and the fossil record seems to support an Early Tertiary diversification. Here, we present the first well-resolved molecular phylogeny for Neoaves, together with divergence time estimates calibrated with a large number of stratigraphically and phylogenetically well-documented fossils. Our study defines several well-supported clades within Neoaves. The calibration results suggest that Neoaves, after an initial split from Galloanseres in Mid-Cretaceous, diversified around or soon after the K/T boundary. Our results thus do not contradict palaeontological data and show that there is no solid molecular evidence for an extensive pre-Tertiary radiation of Neoaves.
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| 8. |
- Ericson, Per G. P., et al.
(författare)
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Diversification of Neoaves through time : Integration of molecular sequence data and fossils
- 2006
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Ingår i: Biology Letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 2:4, s. 543-547
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Tidskriftsartikel (refereegranskat)abstract
- Patterns of diversification and timing of evolution within Neoaves, which includes almost 95% of all bird species, are virtually unknown. On the other hand, molecular data consistently indicate a Cretaceous origin of many neoavian lineages and the fossil record seems to support an Early Tertiary diversification. Here, we present the first well-resolved molecular phylogeny for Neoaves, together with divergence time estimates calibrated with a large number of stratigraphically and phylogenetically well-documented fossils. Our study defines several well-supported clades within Neoaves. The calibration results suggest that Neoaves, after an initial split from Galloanseres in Mid-Cretaceous, diversified around or soon after the K/T boundary. Our results thus do not contradict palaeontological data and show that there is no solid molecular evidence for an extensive pre-Tertiary radiation of Neoaves.
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| 9. |
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| 10. |
- Ettema, Thijs J. G., et al.
(författare)
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The alpha-proteobacteria : the Darwin finches of the bacterial world
- 2009
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Ingår i: Biology Letters. - : The Royal Society. - 1744-9561 .- 1744-957X. ; 5:3, s. 429-432
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Tidskriftsartikel (refereegranskat)abstract
- The alpha-proteobacteria represent one of the most diverse bacterial subdivisions, displaying extreme variations in lifestyle, geographical distribution and genome size. Species for which genome data are available have been classified into a species tree based on a conserved set of vertically inherited core genes. By mapping the variation in gene content onto the species tree, genomic changes can be associated with adaptations to specific growth niches. Genes for adaptive traits are mostly located in 'plasticity zones' in the bacterial genome, which also contain mobile elements and are highly variable across strains. By physically separating genes for information processing from genes involved in interactions with the surrounding environment, the rate of evolutionary change can be substantially enhanced for genes underlying adaptation to new growth habitats, possibly explaining the ecological success of the alpha-proteobacterial subdivision.
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