Dispersal and recruitment ofTasiagma ciliata(Trichoptera: Tasimiidae) in rainforest streams, south‐eastern Australia

Abstract

1. This study examined genetic variation within and among populations of the caddis fly Tasiagma ciliata (Tasimiidae: Trichoptera) from rainforest streams in south‐east Queensland, Australia. 2. Very low levels of genetic differentiation at large spatial scales, between subcatchments and between catchments, indicated that dispersal by the winged adults is widespread. However, significant genetic differentiation at the smallest spatial scale examined, within reaches in a single stream, suggested limited movement by larvae within streams. 3. A patchy distribution of deviations from Hardy–Weinberg equilibrium and differences in patterns among allozyme loci suggested that populations in particular reaches were the result of only a few matings. 4. These results are surprising, given the large numbers of larvae present within a single reach. We suggest that stochastic effects of recruitment may underlie much of the spatial and temporal variation in population numbers in these rainforest streams.

Genetic differentiation among populations ofBaetis rhodani(Ephemeroptera, Baetidae) in three Italian streams

“…Furthermore, deviations were not referable to a single or particular locus, as might have been supposed in case of errors in gel running and subsequent interpretation. Similar findings were reported by different studies dealing with the population genetic structure of some mayfly species belonging to the Baetidae family, together with other freshwater invertebrates, living in some Australian rainforest streams (Bunn & Hughes, 1997;Hughes et al, 1998;Hughes et al, 2000Hughes et al, , 2003aSchmidt et al, 1995). Monaghan et al (2001Monaghan et al ( , 2002, by investigating the genetic differentiation of Baetis alpinus in fragmented Alpine streams, reported hétérozygote deficiencies even more pronounced than those observed by Schmidt et al (1995) and Bunn & Hughes (1997).…”

Population structure of Macrobrachium australiense (Decapoda: Palaemonidae) in Western Queensland, Australia: the role of contemporary and historical processes

“…Some aquatic insects possess a flying stage in their life cycle, which allows them to disperse across drainage boundaries (Hughes et al, 1998;Miller et al, 2002). However, movements of continuously aquatic freshwater species are very much limited by the physical nature and arrangement of the riverine system (Hurwood and Hughes, 2001;McGlashan and Hughes, 2001) and often species with apparently good dispersal abilities present surprisingly high levels of population subdivision (Hughes et al, in review;Hughes and Hillyer, 2003).…”

Mitochondrial DNA signatures of restricted gene flow within divergent lineages of an atyid shrimp (Paratya australiensis)

“…Generally, it appears that, for groups such as insects possessing a flying stage within their life history, dispersal is widespread within and between drainages (eg Schmidt et al, 1995;Hughes et al, 1998;Miller et al, 2002), although there are exceptions such as blepheracerid midges, which show very restricted dispersal patterns even among streams in the same subcatchment (Wishart and Hughes, 2003).…”