DOI: 10.5061/dryad.7k2d1
title: Data from: How topography induces reproductive asynchrony and alters gypsy moth invasion dynamics

description: 1. Reproductive asynchrony, a temporal mismatch in reproductive maturation
 between an individual and potential mates, may contribute to mate-finding
 failure and Allee effects that influence the establishment and spread of
 invasive species. Variation in elevation is likely to promote variability
 in maturation times for species with temperature-dependent development,
 but it is not known how strongly this influences reproductive asynchrony
 or the population growth of invasive species. 2. We examined whether
 spatial variation in reproductive asynchrony, due to differences in
 elevation and local heterogeneity in elevation (hilliness), can explain
 spatial heterogeneity in the population growth rate of the gypsy moth,
 Lymantria dispar (L.), along its invasion front in Virginia and West
 Virginia, USA. 3. We used a spatially explicit model of the effects of
 reproductive asynchrony on mating success to develop predictions of the
 influences of elevation and elevational heterogeneity on local population
 growth rates. Population growth rates declined with increased elevation
 and more modestly with increased elevational heterogeneity. As in earlier
 work, we found a positive relationship between the population growth rate
 and the number of introduced egg masses, indicating a demographic Allee
 effect. At high elevations and high heterogeneity in elevation, the
 population growth rate was lowest and the density at which the population
 tended to replace itself (i.e., the Allee threshold) was highest. 4. An
 analysis of 22 years of field data also showed decreases in population
 growth rates with elevation and heterogeneity in elevation that were
 largely consistent with the model predictions. 5. These results highlight
 how topographic characteristics can affect reproductive asynchrony and
 influence mate-finding Allee effects in an invading non-native insect
 population. Given the dependence of developmental rates on temperature in
 poikilotherms, topographic effects on reproductive success could
 potentially be important to the population dynamics of many organisms.
description: field_data_tabularThese data represent gypsy moth population growth rates, topographic characteristics, and resource density over 22850 1x1 km locations in western Virginia and West Virginia, USA. They were derived from a combination of sources. Gypsy moth population data were derived from pheromone-baited trap catch data provided by the gypsy moth Slow the Spread Program, Inc. The basal area of gypsy moth preferred host trees is from: Morin, et al. 2005. Mapping host-species abundance of three major exotic forest pests. USDA Forest Service Research Paper NE-726. Topographic variables were derived from a digital elevation model from the National Elevation Dataset, United States Geologic Survey (2009). Please find additional details in the ReadMe file.lambda_wgtlag.csvmating_success_model_commentedR code for a model of gypsy moth mating success with phenology varying due to changes in elevation and latitude. Comments to aid in understanding the model are provided in-code.