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Publications (2)2.25 Total impact

  • Alison Joan McLean, Daniel J. Schmidt, Jane M. Hughes
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    ABSTRACT: Long-distance dispersal might be an important mechanism for the maintenance of aquatic insect populations in heterogeneous landscapes. However, these events can be difficult to measure by direct observation because the techniques can be time-consuming, expensive and technically difficult. When dispersal results in gene flow within and between populations, patterns of variation can be detected by genetic methods. The levels of population genetic structuring and the relationship between gene flow and geographical distance were assessed in the mayfly species Bungona narilla (Harker, 1957) in rainforest streams in south-east Queensland that are separated by lowland habitats. An analysis of molecular variance based on mitochondrial DNA data, using a fragment of the cytochrome oxidase I gene, revealed significant differentiation between regions, suggesting that maternal gene flow was restricted. A nested clade analysis revealed patterns of historical (contiguous) range expansions and recent restricted gene flowalong with some long-distance dispersal events. Our analyses have shown that populations of B. narilla are significantly structured throughout the species range in south-east Queensland and that the low elevation habitats separating the northern and southern populations are restricting gene flow to some extent. Yes Yes
    Marine and Freshwater Research 01/2008; · 2.25 Impact Factor
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    ABSTRACT: This chapter synthesizes data from 41 studies on 32 species of stream insects in an attempt to answer three questions: First, what is the major dispersal mechanism in aquatic insects, i.e. stream drift or adult flight? If it is stream drift, then genetic variation would be expected to fit the Stream Hierarchy Model of Meffe and Vrijenhoek (1988). If it is adult flight, populations would be expected to be panmictic at small scales, i.e. among populations in neighbouring catchments. Most stream insects with an adult flight stage do not fit the Stream Hierarchy Model, suggesting that adult flight is the major mechanism of dispersal. Second, at what scale are populations of stream insects structured? Across all studies, there was a signifi cant positive relationship between FST and geographic distance for studies using mitochondrial DNA. The isolation-by-distance relationship for allozyme studies was significant only when studies with high numbers of Hardy Weinberg Equilibrium (HWE) deviations were excluded. Third, what can recent analysis of DNA sequence data contribute to our understanding of historical processes affecting stream insects? Several recent phylogeographic studies using mitochondrial DNA sequence data provide evidence of population and range expansions and contractions, along with past fragmentation, all estimated to have occurred during the Pleistocene. Yes Yes