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Intra-specific Genetic Variation (intra-specific + genetic_variation)
Selected AbstractsCan intra-specific genetic variation in arbuscular mycorrhizal fungi (Glomus etunicatum) affect a mesophyll-feeding herbivore (Tupiocoris notatus Distant)?ECOLOGICAL ENTOMOLOGY, Issue 4 2007STUART C. WOOLEY Abstract 1.,Arbuscular mycorrhizal fungal (AMF) infection can have negative, positive or neutral effects on insect herbivore populations, but patterns are difficult to predict. 2.,Intra-specific genetic variation in nutrient uptake ability between fungal isolates may also have indirect effects on insect herbivores due to changes in plant quality. In preliminary studies mirid (Tupiocoris notatus) populations were significantly reduced on tobacco (Nicotiana rustica) colonised by AMF but it was unknown if same-species fungal isolates differed in their effect. 3.,An experiment was performed as a first test of the effect of intra-specific genetic variation in the mycorrhizal fungus Glomus etunicatum on mirid nymphal population structure, dynamics, and growth rate. 4.,Mirid nymphal populations were lower on mycorrhizal fungal-infected plants. Population size, however, did not differ between the mycorrhizal isolates. While no statistical difference in population between isolates was found, one isolate consistently had 1.7,2.4 times lower mirid populations compared with the controls, indicating that the magnitude of effect is different between mycorrhizal isolates. 5.,The significantly negative effect of AMF on mirid populations likely resulted from AMF-induced changes in plant quality (e.g. increased defence). This study lends further support to recent demonstrations that below-ground symbionts significantly influence above-ground processes. In addition, mycorrhizal fungi can affect insect population structure, which may have consequences for future herbivory. [source] Continental speciation in the tropics: contrasting biogeographic patterns of divergence in the Uroplatus leaf-tailed gecko radiation of MadagascarJOURNAL OF ZOOLOGY, Issue 4 2008C. J. Raxworthy Abstract A fundamental expectation of vicariance biogeography is for contemporary cladogenesis to produce spatial congruence between speciating sympatric clades. The Uroplatus leaf-tailed geckos represent one of most spectacular reptile radiations endemic to the continental island of Madagascar, and thus serve as an excellent group for examining patterns of continental speciation within this large and comparatively isolated tropical system. Here we present the first phylogeny that includes complete taxonomic sampling for the group, and is based on morphology and molecular (mitochondrial and nuclear DNA) data. This study includes all described species, and we also include data for eight new species. We find novel outgroup relationships for Uroplatus and find strongest support for Paroedura as its sister taxon. Uroplatus is estimated to have initially diverged during the mid-Tertiary in Madagascar, and includes two major speciose radiations exhibiting extensive spatial overlap and estimated contemporary periods of speciation. All sister species are either allopatric or parapatric. However, we found no evidence for biogeographic congruence between these sympatric clades, and dispersal events are prevalent in the dispersal,vicariance biogeographic analyses, which we estimate to date to the Miocene. One sister-species pair exhibits isolated distributions that we interpret as biogeographic relicts, and two sister-species pairs have parapatric distributions separated by elevation. Integrating ecological niche models with our phylogenetic results finds both conserved and divergent niches between sister species. We also found substantial intra-specific genetic variation, and for the three most widespread species, poor intra-specific predictive performance for ecological niche models across the latitudinal span of Madagascar. These latter results indicate the potential for intra-specific niche specialization along environmental gradients, and more generally, this study suggests a complex speciation history for this group in Madagascar, which appears to include multiple speciation processes. [source] | ||||||||||