title: The small-scale spatial distribution of an invading moth.
abstract: We studied the spread of a small leaf-mining moth [Phyllonorycter leucographella (Zeller), Gracillariidae] after its accidental introduction into the British Isles. At large geographical scales, previous work had shown the spread to be well described by a travelling weve of constant velocity. Here, we report the pattern of spread at scales of 1 km2. By locating all bushes of the insect's foodplant (Pyracantha spp.) within 1-km2quadrats, the precise pattern of colonisation at finer spatial scales could be established. Where the 1-km2site was colonised by moths from the main advancing front, no spatial pattern in the order that bushes were infested was found. If the source of colonisation was a single or small group of infested plants within the site, there was some evidence that nearby plants were colonised first. We found no evidence of population turnover after colonisation. We interpret the results in terms of a two-stage model of invasion that produces different patterns at small and large geographical scales.
authors.affiliation: Department of Biology and NERC Centre for Population Biology, Imperial College at Silwood Park, SL5 7PY, Ascot, Berks, UK.
authors.forename: David R
authors.initials: DR
authors.lastname: Nash
authors.affiliation: Department of Biology and NERC Centre for Population Biology, Imperial College at Silwood Park, SL5 7PY, Ascot, Berks, UK.
authors.forename: David J L
authors.initials: DJ
authors.lastname: Agassiz
authors.affiliation: Department of Biology and NERC Centre for Population Biology, Imperial College at Silwood Park, SL5 7PY, Ascot, Berks, UK.
authors.forename: H C J
authors.initials: HC
authors.lastname: Godfray
authors.affiliation: Department of Biology and NERC Centre for Population Biology, Imperial College at Silwood Park, SL5 7PY, Ascot, Berks, UK.
authors.forename: John H
authors.initials: JH
authors.lastname: Lawton
keywords: Dispersal; Invasion; Leaf miner; Population dynamics; Spatial scale