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JORDAENS KURT; RIEL PATRICK VAN; GEENEN SOFIE; VERHAGEN RON; BACKELJAU THIERRY 《Journal of Molluscan Studies》2001,67(2):161-167
Body pigmentation is a popular taxonomic marker in slugs to
discriminateclosely related species. However, the genetic background
ofbody pigmentation is known only for a few species, while inmany
others body pigmentation is influenced by age, food and/orclimate. In
this study, we investigated the effects of differentfood items on
body pigmentation expression in two selfing pulmonategastropods,
Arion (Carinarion) silvaticus and Arion (Carinarion)
fasciatus.Both species mainly differ in the distribution of
yellow-orangegranules on the body, which in A. fasciatus are
concentratedin lateral bands, and in A. silvaticus are evenly
scattered.Animals were raised individually under the same conditions,
whilethey laid eggs as a consequence of selfing. This F1 generation
wasafterwards divided into two groups, which were fed with different
fooditems. A diet of carrot, lettuce or paper had no effect on the
distributionof the yellow-orange granules in A. silvaticus, but
provokeda loss of the yellow-orange lateral bands in A. fasciatusso that externally these F1
specimens became similar to A. silvaticus.In both species, a
diet of nettle resulted in a strong yellow-orangepigmentation, which
often formed yellow-orange lateral bands.These results indicate that
food can probably influence the'species-specific' body pigmentation in
Carinarion, and thusquestion the reliability of colour traits to
distinguish A.silvaticus and A. fasciatus. (Received 5 May 2000; accepted 29 September 2000) 相似文献
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KURT JORDAENS LOBKE DILLEN THIERRY BACKELJAU 《Biological journal of the Linnean Society. Linnean Society of London》2009,96(2):306-321
Previous work suggests that low-spired hermaphroditic snails mate face-to-face and have reciprocal sperm exchange, whereas high-spired snails mate by shell mounting and have unilateral sperm exchange. This dichotomy lead others to speculate on the evolution of enigmatic mating behaviours and whole-body enantiomorphy. In the present study, we review the current literature on mating behaviour in pulmonate snails and show that: (1) several pulmonate species show considerable intraspecific variation in mating behaviour; (2) mating position does not predict reciprocity of penis intromission and sperm exchange; (3) dart-shooting may be correlated with reciprocity of sperm exchange but other factors must explain the gain or loss of darts; (4) it is unlikely that the degree of reciprocity is the most important factor in explaining the relationship of whole-body enantiomorphy and shell shape; and (5) the reciprocal intromission of penises does not necessarily involve the reciprocal transfer of sperm. Hence, our survey shows that current ideas on the evolutionary relationship between shell shape and reciprocity with sexual selection (including dart-use) and whole-body enantiomorphy in hermaphroditic snails should be refined. The results obtained demonstrate that our current knowledge on gastropod mating behaviour is too limited to detect general evolutionary trajectories in gastropod mating behaviour and genital anatomy. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 96 , 306–321. 相似文献
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HEIKE KAPPES KURT JORDAENS NATALIE VAN HOUTTE FREDERIK HENDRICKX JEAN‐PIERRE MAELFAIT LUC LENS THIERRY BACKELJAU 《Biological journal of the Linnean Society. Linnean Society of London》2009,98(4):839-850
Habitat fragmentation may influence the genetic structure of populations, especially of species with low mobility. So far, these effects have been mainly studied by surveying neutral markers, and much less by looking at ecologically relevant characters. Therefore, we aimed to explore eventual patterns of covariation between population structuring in neutral markers and variation in shell morphometrics in the forest‐associated snail Discus rotundatus in relation to habitat fragment characteristics. To this end, we screened shell morphometric variability and sequence variation in a fragment of the mitochondrial 16S rDNA gene in D. rotundatus from the fragmented landscape of the Lower Rhine Embayment, Germany. The 16S rDNA of D. rotundatus was highly variable, with a total of 118 haplotypes (384 individuals) forming four clades and one unresolved group. There was a geographic pattern in the distribution of the clades with the river Rhine apparently separating two groups. Yet, at the geographic scale considered, there was no obvious effect of fragmentation on shell morphometrics and 16S rDNA variation because GST often was as high within, as between forests. Instead, the age of the habitat and (re‐)afforestation events appeared to affect shell shape and 16S rDNA in terms of the number of clades per site. The ecologically relevant characters thus supported the presumably neutral mitochondrial DNA markers by indicating that populations of not strictly stenecious species may be (relatively) stable in fragments. However, afforestation after large clearcuts and habitat gain after the amendment of deforestation are accompanied by several, seemingly persistent peculiarities, such as altered genetic composition and shell characters (e.g. aperture size). © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98 , 839–850. 相似文献
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Population genetics and shell morphology have been studiedin 11
populations of the poorly colonizing land caenogastropodPomatias
elegans. The total area of suitable habitats in northwestEurope is
shrinking and many isolated populations are becomingvulnerable to
extinction. In this study we tested whether theconcept of management
units (i.e. groups of population withsignificantly different allele
frequencies due to demographicindependence) is applicable to the
conservation of P. elegans.Fst values indicated strong genetic
differentiation and thuslittle genetic exchange between
populations. Allozyme differentiationcould be explained with an
isolation by distance model, whereasmorphological differentiation
could not. A morphological differenceexists between sexes but not
sufficient to discriminate malesand females. A Mantel test showed no
significant relationshipbetween morphological distance (size
corrected or not) and geneticdistance. Since allele frequencies
differed even among populationsin areas where P. elegans is not
threathened, we conclude thatin the case of P. elegans, defining
management units with allozymesmay not be an appropriate way to
select the most suitable populationsfor conservation. (Received 3 April 2000; accepted 25 August 2000) 相似文献
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KURT JORDAENS PATRICK VAN RIEL ANTONIO M. FRIAS MARTINS THIERRY BACKELJAU 《Biological journal of the Linnean Society. Linnean Society of London》2009,97(1):166-176
Morphological data, in combination with molecular data, may provide invaluable insights into speciation processes on archipelagos. Land snails offer ample opportunities to evalutate adaptive and non-adaptive speciation scenarios. However, studies investigating processes of differentiation and speciation on the Azores are scarce. The present study comprises a morphometrical analysis of shell and genital characters in a group of Azorean land snails (Pulmonata, Leptaxinae). Geographical isolation appears to be an important mechanism underlying morphological and molecular differentiation in the Azorean Leptaxini, instead of adaptive radiation through ecological differentiation. Nevertheless, we could not exclude the occurrence of ecological speciation on the oldest island (Santa Maria) where two species that markedly differ in shell-shape co-occur. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 97 , 166–176. 相似文献
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J. PINCEEL K. JORDAENS N. VAN HOUTTE A. J. DE WINTER T. BACKELJAU 《Biological journal of the Linnean Society. Linnean Society of London》2004,83(1):23-38
The importance and abundance of cryptic species among invertebrate taxa is well documented. Nowadays, taxonomic, phylogenetic and conservation biological studies frequently use molecular markers to delineate cryptic taxa. Such studies, however, often face the problem of the differential resolution of the molecular markers and techniques involved. This issue is explored in the present study of cryptic taxa within the terrestrial slug complex Arion subfuscus/fuscus in continental north-west Europe. To this end, morphological, allozyme and mitochondrial 16S rDNA sequence data have been jointly evaluated. Using allozyme data and gonad type, two distinct groups were consistently delineated, even under sympatric conditions. The 16S rDNA data strongly supported both those groups and even suggested the presence of three distinct taxa within one of them. However, in view of: (1) the allopatric distribution of three OTUs, (2) the lack of allozyme or morphological differentiation, and (3) the extremely high degree of intraspecific mtDNA variation reported in pulmonate gastropods, they are, for the time being, not regarded as valid species under the biological species concept. By means of 16S rDNA and allozyme data, the position of type and topotype material of A. subfuscus s.s. and A. fuscus relative to the newly defined OTUs was determined, thus clarifying the nomenclature of this species complex. Additionally, gonad type proved to be a useful character for distinguishing the two species in north-west Europe. © 2004 The Linnean Society of London, Biological Journal of the Linnean Society , 2004, 83 , 23–38. 相似文献
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Multivariate morphometrics of soft body parts in terrestrial slugs: comparison between two datasets, error assessment and taxonomic implications 总被引:2,自引:0,他引:2
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