Critical patch size generated by Allee effect in gypsy moth, Lymantria dispar (L.)

• Published in: Ecology letters Vol. 14; no. 2; pp. 179 - 186
• Main Authors: Vercken, E, Kramer, A.M, Tobin, P.C, Drake, J.M
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.02.2011; Blackwell; Wiley
• Subjects: Allee effect; Animal and plant ecology; Animal populations; Animal, plant and microbial ecology; Animals; Biological and medical sciences; Butterflies & moths; critical area; dispersal; Ecology; extinction; Female; Fundamental and applied biological sciences. Psychology; General aspects; generalized additive models; gypsy moth; Introduced Species; invasion; Letters; Life Sciences; Lymantria dispar; Male; Moths - physiology; Nonnative species; Population Density; Population Growth; reaction-diffusion; Theory; Time Factors; United States; Voronoi tessellation; United States; USA; Lymantriidae; Extinction; Voronoi tessellation; Insecta; Allee effect; dispersal; Additive model; Dispersion; Invasion; reaction-diffusion; critical area; generalized additive models; Arthropoda; Lepidoptera; gypsy moth; Invertebrata; Diffusion; Lymantria dispar; GYPSY MOTH; ALLEE EFFECT; REACTION-DIFFUSION; GENERALIZED ADDITIVE MODELS; LYMANTRIIDAE; VORONOI TESSELLATION; DISPERSAL; INVASION; CRITICAL AREA; PRINCIPE ALLEE; LEPIDOPTERA; EXTINCTION; LYMANTRIA DISPAR
• ISSN: 1461-023X; 1461-0248
• DOI: 10.1111/j.1461-0248.2010.01569.x

Ecology Letters (2011) 14: 179-186 ABSTRACT: Allee effects are important dynamical mechanisms in small-density populations in which per capita population growth rate increases with density. When positive density dependence is sufficiently severe (a ‘strong' Allee effect), a critical density arises below which populations do not persist. For spatially distributed populations subject to dispersal, theory predicts that the occupied area also exhibits a critical threshold for population persistence, but this result has not been confirmed in nature. We tested this prediction in patterns of population persistence across the invasion front of the European gypsy moth (Lymantria dispar) in the United States in data collected between 1996 and 2008. Our analysis consistently provided evidence for effects of both population area and density on persistence, as predicted by the general theory, and confirmed here using a mechanistic model developed for the gypsy moth system. We believe this study to be the first empirical documentation of critical patch size induced by an Allee effect.