Environmental factors influencing immigration behaviour of the invasive earthworm Lumbricus terrestris
Abstract:Despite the ecological threats posed to northeastern North American forests by the invasive earthworm Lumbricus terrestris L., 1758 (Oligochaeta: Lumbricidae), the dispersal behaviour of this organism is poorly understood. This study investigated how environmental conditions influence the immigration behaviour of L. terrestris. Experimental mesocosms were used to test for differences in burrow establishment depending on leaf-litter type (sugar maple (Acer saccharum Marsh.) or white pine (Pinus strobus L.)) or the background population density of conspecifics (0, 25, or 100 m−2). Choice chambers were used to test for selection between habitat conditions. Video recording was used to measure the latency between introduction and establishment. A significantly greater proportion of individuals established burrows in the presence of maple over pine litter, although this preference did not result in a significant difference in latency. For higher population density treatments, the time since establishment of the background population of conspecifics had a significant effect on earthworm habitat selection, with an increasing preference for the high-density habitat over time. Population density had a significant effect on latency, with greater latency under low-density conditions. These results suggest that L. terrestris detects differences in litter type and conspecific population density and modifies its immigration behaviour accordingly. Findings may be useful in predicting and responding to future dispersal patterns of this invader.
Keywords: Lumbricus terrestris; common nightcrawler; couverture de feuilles mortes; density-dependent dispersal; dispersion dépendante de la densité; immigration; leaf litter; lombric commun; mesocosm; mésocosme
Document Type: Research Article
Affiliations: 1: University of Toronto Mississauga, Department of Geography, 3359 Mississauga Road North, Mississauga, ON L5L 1C6, Canada. 2: University of Toronto, Faculty of Forestry, 33 Willcocks Street, Toronto, ON M5S 3B3, Canada.
Publication date: January 1, 2013
- Published since 1929, this monthly journal reports on primary research contributed by respected international scientists in the broad field of zoology, including behaviour, biochemistry and physiology, developmental biology, ecology, genetics, morphology and ultrastructure, parasitology and pathology, and systematics and evolution. It also invites experts to submit review articles on topics of current interest.
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