Search publications of the members of the Royal Belgian institute of natural Sciences
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Selection for costly traits result in a vacant mating niche and in the evolution of a genetic male dimorphism
- The expected strong directional selection for traits that increase a male’s mating ability conflicts with the frequent observation that within species, males may show extreme variation in sexual traits. These male reproductive polymorphisms are usually attributed to direct male–male competition. It is currently unclear, however, how directional selection for sexually selected traits may convert into disruptive selection, and if female preference for elaborate traits may be an alternative mechanism driving the evolution of male polymorphism. Here, we explore this mechanism using the polyandric dwarf spider Oedothorax gibbosus as a model. We first show that males characterized by conspicuous cephalic structures serving as a nuptial feeding device (“gibbosus males”) significantly outperform other males in siring offspring of previously fertilized females. However, significant costs in terms of development time of gibbosus males open a mating niche for an alternative male type lacking expensive secondary sexual traits. These “tuberosus males” obtain virtually all fertilizations early in the breeding season. Individual-based simulations demonstrate a hitherto unknown general principle, by which males selected for high investment to attract females suffer constrained mating opportunities. This creates a vacant mating
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Evolutionary history of a dispersal-associated locus across sympatric and allopatric divergent populations of a wing-polymorphic beetle across Atlantic Europe
- Studying the evolutionary history of trait divergence, in particular those related to dispersal capacity, is of major interest for the process of local adaptation and metapopulation dynamics. Here, we reconstruct the evolution of different alleles at the nuclear-encoded mitochondrial NADP+-dependent isocitrate dehydrogenase (mtIdh) locus of the ground beetle Pogonus chalceus that are differentially and repeatedly selected in short- and long-winged populations in response to different hydrological regimes at both allopatric and sympatric scales along the Atlantic European coasts. We sequenced 2788 bp of the mtIdh locus spanning a ~7-kb genome region and compared its variation with that of two supposedly neutral genes. mtIdh sequences show (i) monophyletic clustering of the short-winged associated mtIDH-DE haplotypes within the long-winged associated mtIDH-AB haplotypes, (ii) a more than tenfold lower haplotype diversity associated with the mtIDH-DE alleles compared to the mtIDH-AB alleles and (iii) a high number of fixed nucleotide differences between both mtIDH haplotype clusters. Coalescent simulations suggest that this observed sequence variation in the mtIdh locus is most consistent with a singular origin in a partially isolated subpopulation, followed by a relatively recent spread of the mtIDHDE allele in short-winged populations along the Atlantic coast. These results demonstrate that even traits associated with decreased dispersal capacity can rapidly spread and that reuse of adaptive alleles plays an important
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Endosymbiont dominated bacterial communities in a dwarf spider
- The microbial community of spiders is little known, with previous studies focussing primarily on the medical importance of spiders as vectors of pathogenic bacteria and on the screening of known cytoplasmic endosymbiont bacteria. These screening studies have been performed by means of specific primers that only amplify a selective set of endosymbionts, hampering the detection of unreported species in spiders. In order to have a more complete overview of the bacterial species that can be present in spiders, we applied a combination of a cloning assay, DGGE profiling and high-throughput sequencing on multiple individuals of the dwarf spider Oedothorax gibbosus. This revealed a co-infection of at least three known (Wolbachia, Rickettsia and Cardinium) and the detection of a previously unreported endosymbiont bacterium (Rhabdochlamydia) in spiders. 16S rRNA gene sequences of Rhabdochlamydia matched closely with those of Candidatus R. porcellionis, which is currently only reported as a pathogen from a woodlouse and with Candidatus R. crassificans reported from a cockroach. Remarkably, this bacterium appears to present in very high proportions in one of the two populations only, with all investigated females being infected. We also recovered Acinetobacter in high abundance in one individual. In total, more than 99% of approximately 4.5M high-throughput sequencing reads were restricted to these five bacterial species. In contrast to previously reported screening studies of terrestrial arthropods, our results suggest that the bacterial communities in this spider species are dominated by, or even restricted to endosymbiont bacteria. Given the high prevalence of endosymbiont species in spiders, this bacterial community pattern could be widespread in the Araneae order.
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Differentiation, selection and speciation in the salt marsh beetle Pogonus chalceus.
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The MODIRISK project: a large scaled survey on mosquito biodiversity as basis for risk assessment and control.
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Spider colonisation and source-sink effects in newly developed dunes and dikes along the river IJzer estuary.
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Patterns in speciation in wolf spiders from the Galapagos Archipelago: A case of ecological speciation?
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Notes on the beach-dwelling genus Chersodromia (Diptera: Hybotidae) from Tunisia: description of a new brachypterous species with notes on brachyptery in empidoids.
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Superfamily Empidoidea. Family Hybotidae.
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New and little-known species of the genus Tachydromia Meigen (Diptera, Hybotidae) from Thailand
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Divergence patterns of an adaptively radiated wolf spider genus on Galapagos
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The interaction of professional and non-professional entomologists in Flanders (Belgium): is this relationship really working.
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De Kesselberg binnenste buiten, een realisatie van Hona vzw
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Diep onder de Kesselberg: een half miljard jaar Leuvense geschiedenis in een notendop.
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In de Kesselberg: zeezand in een heuvel
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Vorming van de Kesselberg: over erosie, rivierterrassen, de Vlaamse Vallei, mammoeten en de mens.
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Erfgoed Aarde. Een kijk op mens en natuur vroeger en nu, een realisatie van Hona vzw
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De rol van de amateur
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Compilatie van de literatuur handelend over de spinnen van België verschenen in 2005 tot en met 2007.
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The virus vector family Trichodoridae (Nematoda), a source of many unknown cryptic species
