Search publications of the members of the Royal Belgian institute of natural Sciences
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Empidine dance flies from Singapore and southern Malaysia (diptera: Empididae: Empidinae)
- Five new species belonging to the Empis (Coptophlebia) hyalea-group are described, namely E. (C.) neesoonensis, new species, E. (C.) producta, new species, E. (C.) tortuosa, new species, E. (C.) triseta, new species and E. (C.) verruca, new species. A key to all known species of the group is provided for Singapore and Southern Malaysia. © National University of Singapore.
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Atypical mating behaviour in the empidine dance fly Rhamphomyia (Lundstroemiella) magellensis (Diptera : Empididae : Empidinae)
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Spatiotemporal allozyme variation in the damselfly, Lestes viridis (Odonata: Zygoptera): Gene flow among permanent and temporary ponds
- Several insect species seem to persist not only in permanent but also in temporary ponds where they face particularly harsh conditions and frequent extinctions. Under such conditions, gene flow may prevent local adaptation to temporary ponds and may promote phenotypic plasticity, or maintain apparent population persistence. The few empirical studies on insects suggest the latter mechanism, but no studies so far quantified gene flow including both pond types. We investigated the effects of pond type and temporal variation on population genetic differentiation and gene flow in the damselfly Lestes viridis in northern Belgium. We report a survey of two allozyme loci (Gpi, Pgm) with polyacrylamide gel electrophoresis in 14 populations from permanent and temporary ponds, and compared these results with similar data from the same permanent populations one year before. The data suggested that neither pond-drying regime, nor temporal variation have a substantial effect on population genetic structuring and did not provide evidence for stable population differentiation in L. viridis in northern Belgium. Gene flow estimates were high within permanent and temporary ponds, and between pond types. Our data are consistent with a source-sink metapopulation system where temporary ponds act as sinks in dry years, and are quickly recolonized after local population extinction. This may create a pattern of apparent population persistence of this species in permanent and temporary ponds without clear local adaptation. © Springer 2005.
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Mitochondrial DNA variation and cryptic speciation within the free-living marine nematode Pellioditis marina
- An inverse correlation between dispersal ability and genetic differentiation among populations of a species is frequently observed in the marine environment. We investigated the population genetic structure of the free-living marine nematode Pellioditis marina. A total of 426 bp of the mitochondrial cytochrome oxidase subunit 1 (COI) gene were surveyed on a geographical scale of approximately 100 km during spring 2003. Nematodes were collected from 2 coastal locations in Belgium, and from 2 estuaries and a saltwater lake (Lake Grevelingen) in The Netherlands. Molecular variation was assessed with the single-strand conformation polymorphism (SSCP) method. In total, 32 different haplotypes were observed, and sequence divergence among 452 individuals ranged from 0.2 to 10.6\%. We discovered 4 distinct mitochondrial lineages, with low divergences within the lineages (0.2 to 1.6\%) and high divergences between the lineages (5.1 to 10.6\%). The nuclear ribosomal ITS (internal transcribed spacer) region showed concordant phylogenetic patterns, suggesting that nematode species diversity may be considerably underestimated. Analysis of molecular variance (AMOVA) indicated a strong genetic differentiation among populations. The Lake Grevelingen population was clearly differentiated from all other populations, but genetic structuring was also significant within the Westerschelde and was correlated with gradients in salinity and pollution. The observed population genetic structure is in accordance with the limited active dispersal capacity of P. marina, but is at variance with its significant potential for passive dispersal. We therefore suggest that autecological characteristics, including short generation time, high colonization potential and local adaptation, may be at the basis of this nematode's population genetic structure. © Inter-Research 2005.
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A wingless intertidal ground beetle, new to the Belgian fauna, in the river IJzer estuary nature restoration site: Bembidion nigropiceum Marsham, 1802
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Bottlenecks, drift and differentiation: The fragmented population structure of the saltmarsh beetle Pogonus chalceus
- We investigated the distribution of genetic variation within and between 10 fragmented populations of the saltmarsh beetle Pogonus chalceus in the region of Flanders (Belgium) representing all extant populations of the species in that region by using allozyme and microsatellite markers. Beetle population size and habitat area failed to explain a significant part of the genetic variability. Microsatellite allelic diversity was sensitive to population size differences but not to saltmarsh area estimates. Heterozygosities of both marker types and allozyme allelic diversity on the other hand showed no significant correlation to population size and saltmarsh area. There was also no correlation between geographical and genetic distances among populations. Evidence was found for past bottlenecks in some of the smallest populations. Maximum likelihood methods using the coalescent approach revealed that the proportion of common ancestors was also high in those small populations. 35\% of our studied individuals, especially in the largest populations showed a relative wing size smaller than 70\%. Moreover, only six out of the 10 studied populations showed a few individuals with functional flight musculature. In conclusion, the overall pattern of distribution of genetic variation and the low flight capacity did not support an equilibrium model of population structure in P. chalceus, but mainly suggested a lack of regional equilibrium with both drift and gene flow influences. © Springer 2005.
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Genetic differentiation among populations of the salt marsh beetle Pogonus littoralis (Coleoptera: Carabidae): A Comparison between Atlantic and Mediterranean populations
- Genetic differentiation was studied among populations of the salt marsh beetle Pogonus littoralis (Coleoptera: Carabidae), comparing Atlantic and Mediterranean populations over a large part of its range. The genetic structure of this highly mobile beetle was investigated by studying allozyme polymorphism at nine enzyme loci in 13 populations. Mediterranean P. littoralis were highly significantly differentiated from Atlantic populations. Moreover, more isolated Atlantic populations showed increased differentiation and decreased genetic diversity compared to less fragmented Mediterranean populations. © The American Genetic Association. 2005. All rights reserved.
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Linking science and policy for biodiversity
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The continuous exploitation of wild animal resources in the archaeozoological record of Ghana
- The paper provides a critical review of the archaeozoological information from Ghanaian sites published up to now and summarizes the new faunal analysis of several Gonja and Asante sites. The data suggest the persistence of the use of the various wild animal resources available and limited reliance on domestic animals since late prehistoric times up to today, although certain resources such as molluscs, insects etc. may have limited or no visibility. Intensive utilisation of edible wild resources may be prevalent in African woodlands.
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Post-storm surveys reveal large-scale spatial patterns and influences of site factors, forest structure and diversity in endemic bark-beetle populations
- The storm that struck France on december 26th and 28 th 1999 felled 140 million m3 of timber and had a high economic, social and landscape impact. This event offered the opportunity to study large-scale patterns in populations of forest insect pests that would benefit from the abundant breeding material. A large-scale survey was carried out in France in 2000 to sample the most frequently observed species developing on spruce (Ips typographus, Pityogene schalcographus) and pine (Tomicus piniperda, Ips sexdentatus) in 898 locations distributed throughout wind-damaged areas. The local abundance of each species scored on a 0 to 5 scale was analysed using geostatistical estimators to explore the extent and intensity of spatial autocorrelation, and was related to site, stand, and neighbourhood landscape metrics of the forest cover (in particular the interconnection with broadleaf forest patches) found within dispersal distance. All species but I. sexdentatus, which was much less abundant, displayed large-scale spatial dependence and regional variations in abundance. Lower infestation levels per tree (windfalls and standing trees) were observed in stands with a high proportion of wind-damaged trees, which was interpreted as the result of beetles distributing themselves among the available breeding material. More infestations were observed in wind-broken trees as compared to wind-felled trees. More importantly, populations showed significant relationships with the structure of coniferous stands (in particular with the number of coniferous patches). T. piniperda population levels were negatively correlated to the amount of coniferous edge shared with broadleaf forest patches, possibly because of the disruptive effect of non-host volatiles on host-finding processes at the landscape-scale. The differences observed between species regarding patterns and relationships to site, stand, and forest cover characteristics are discussed in relation to the ecological characteristics of each species. © Springer 2005.
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Imitation systems, monkey vocalization, and the human language
- In offering a detailed view of putative steps towards the emergence of language from a cognitive standpoint, Michael Arbib is also introducing an evolutionary framework that can be used as a useful tool to confront other viewpoints on language evolution, including hypotheses that emphasize possible alternatives to suggestions that language could not have emerged from an earlier primate vocal communication system.
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Villala Goemans and O'Brien, a new genus of Fulgoridae (Hemiptera, Fulgoromorpha) with three new species from Mexico, Belize, Guatemala, Honduras, and Costa Rica
- A new genus of Fulgoridae, Villala, with a long head projection, is described with three new species: V. canoi Goemans from Guatemala, Costa Rica, Belize, and Honduras; V. angelica O'Brien from Costa Rica, and V. platyrhina O'Brien from Mexico. A key to the species and comparative notes are included. © Taylor & Francis.
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The loess-palaeosol succession of Kurtak (Yenisei basin, Siberia): A reference record for the Karga Stage (MIS 3)
- The loess-palaeosol succession of Kurtak, along the western slope of the Yenisei Valley, is one of the best documented Late Pleistocene sequences in southern Central Siberia. The present paper deals with the Kurtak Pedocomplex and with the Chani Bay Complex preserved on the plateau and in a lateral depression respectively, which corre pond to the Karga Stage (MIS 3). For this sequence we obtained a detailed palaeoclimatic succession based on pedological and palynological data recording 14 short interstadial periods. The chronology of this record is well established by ca 100 radiocarbon dates on charcoal and wood remains, ranging from 42,520 to 25,710 BP. Botanical analysis shows a steppe-like vegetation with small tree populations (spruce, pine, birch) in lateral valleys during the colder periods. During the interstadial episodes spruce populations grew denser in the valleys, while scattered spruce, larch and pine trees expanded on the plateau. Therefore, the Kurtak Pedocomplex and Chani Bay Complex provide a unique climatic record for MIS 3, similar to the middle pleniglacial succession of the Dinkel Valley in the Netherlands and to loess-palaeosol records of Eastern and Central Europe. This means that the Siberian record shows a climatic sequence of global significance, and that the environmental conditions during MIS 3 were highly unstable at the Eurasian continent.
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Exploitation of kairomones and synomones by Medetera spp. (Diptera: Dolichopodidae), predators of spruce bark beetles
- The semioehemical relationships in a predator-prey-host plant system were studied by a series of multiple-choice field assays. The studied system included predatory flies of the genus Medetera (Diptera: Dolichopodidae), the bark beetles Ips typographus and Pityogenes chalcographus (Coleoptera: Curculionidae: Scolytinae) as prey and Norwegian spruce (Picea abies) as the host plant. Of the nine species of predators collected, only M. setiventris and M. melancholica provided sufficient data for statistical analysis. The response of the predators to monoterpenic products of the host (alpha-pinene, limonene, camphor), pheromone compounds of I. typographus (S-cis-verbenol and 2-methyl-3-buten-2-ol) and a mixture of the pheromones of I. typographys and P. chalcographus were investigated. Our field trials revealed that tree volatiles plus pheromones of the prey, and a pheromone mixture of both prey species were considerably more attractive to M. setiventris and M. melancholica than the individual chemicals. Medetera seem to respond to the stage of tree decay and the intensity of bark beetle infestation via the ratios of tree volatiles and/or prey pheromones.
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Mate choice in the hermaphroditic land snail Succinea putris (Stylommatophora: Succineidae)
- Internally fertilizing hermaphroditic animals show a bewildering variety of mating behaviours and mechanisms and many species have reciprocal sperm exchange. When matings are frequent and costly, partners are predicted to donate more sperm when they receive more sperm (i.e. conditional sperm exchange), but this has been shown experimentally only in sea slugs, free-living flatworms and possibly cestodes. We studied mate choice and sperm reciprocity patterns in the hermaphroditic land snail Succinea putris. Mate choice was random with respect to shell size. However, in matings where the partners were of unequal size, significantly more matings were observed where a small active individual mated on top of a larger inactive individual than the reverse. We suggest that this may be the result of mating on a vertical substrate or hanging underneath a horizontal substrate, because under these conditions it may be easier for a larger, inactive individual to carry a smaller, active one, than vice versa. The number of sperm transferred during mating was highly variable and was not related to the size of the donor, the size of the recipient, the size difference between the two partners or mating duration. Twelve of the 87 matings involved unilateral sperm exchange. There was no evidence for conditional sperm digestion. There was a significant, but weak positive relation between the numbers of sperm donated by the two partners. Hence, it remains unclear whether sperm exchange in S. putris is conditional or not. © 2005 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
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New metallothionein mRNAs in Gobio gobio reveal at least three gene duplication events in cyprinid metallothionein evolution
- This paper reports the identification and analysis of the primary structure of three novel metallothionein cDNA sequences in the gudgeon, Gobio gobio (Cyprinidae). Two different 180 bp coding regions were identified, resulting in two MT isoforms differing in one amino acid. The primary structure of the amino acid sequence was compared to other cyprinid MT sequences. Furthermore, two differently sized cDNAs were discovered in one of the two transcripts. We present a phylogenetic comparison of our sequences to other, previously published cyprinid MT gene sequences. Our analysis reveals an unexpected complexity in cyprinid MT evolution, with at least three gene duplication events. Differences and homologies between the evolution of cyprinid MT genes are compared to other teleost families. Finally, possible implications for metallothionein classification are discussed. © 2005 Elsevier Inc. All rights reserved.
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Paracrenhydrosoma oceaniae sp. nov. (Copepoda: Harpacticoida), from Kongsfjorden, Northwest Svalbard (Arctic)
- Both sexes of a new species of Cletodidae belonging to the Acrenhydrosoma-lineage are described from material collected at Kongsfjorden (Svalbard) and attributed to the genus Paracrenhydrosoma Gee, 1999. Paracrenhydrosoma oceaniae sp. nov. is easily distinguished from its congeners by the reduced setal formula of the natatorial legs, lacking the inner subdistal seta on segment 3 of legs 3 and 4. Several other characteristics viz. antennular and antennal armature, and the free leg 5 exopodite in both sexes, are indications of its basal position in the genus.
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An assessment of animal species diversity in continental waters
- There is a need for monitoring the status and trends of freshwater biodiversity in order to quantify the impacts of human actions on freshwater systems and to improve freshwater biodiversity conservation. Current projects carrying assessment of freshwater biodiversity focus mainly on leading-better-known groups such as fish, or identify keystone species and/or endemic freshwater systems for conservation purposes. Our purpose is to complete these existing projects by providing quantitative estimates of species number for all freshwater groups on each continent and/or major eco-regions. This article present the results of the first implementation phase carried out from September 2002 to June 2003 and which addressed only freshwater animal species. The project consisted of: (1) compiling existing data from literature, web sites and museum collections; (2) contacting scientific experts of each group to provide a 'to the best of their knowledge, estimates of species numbers. In this study, we consider as true freshwater species, those that complete part or all of their life cycle in freshwater, and water-dependant species those that need freshwater for food or that permanently use freshwater habitats. The current order of magnitude for known freshwater animal species world wide is 100 000, of which half are insects. Among other groups, there are some 20 000 vertebrate species; 10 000 crustacean species and 5000 mollusc species that are either true freshwater or water-dependant species. The study highlighted gaps in the basic knowledge of species richness at continental and global scales: (1) Some groups such as Protozoa, nematodes or annelids have been less studied and data on their diversity and distribution is scarce. Because current richness estimates for these groups are greatly biased by knowledge availability, we can expect that real species numbers might be much higher. (2) Continents are not equal in the face of scientific studies: South America and Asia are especially lacking global estimates of species richness for many groups, even for some usually well-known ones such as molluscs or insects. The second phase of the project will address freshwater plants and algae. The present status should be considered as a first sketch of the global picture of freshwater biodiversity. We hope that this project will initiate interactive exchange of data to complete and update this first assessment. © Springer 2005.
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Taxonomy and systematics in biodiversity research
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Revision of the genus Thambemyia Oldroyd (Diptera: Dolichopodidae) with description of a new subgenus
- The genus Thambemyia Oldroyd is revised. Five species are recognized. Three new species - T. bisetosa, T. bruneiensis and T. hui - are described, and T. pagdeni Oldroyd, 1956 is redescribed. A new subgenus is founded for one new Japanese species, T. (Prothambemyia) japonica. A key to all known species of the genus is provided. Their distributions are also discussed. © 2005 The Entomological Society of Japan.
