DOI: 10.5061/dryad.j886dg0
title: Data from: Urbanization-driven changes in web-building and body size in an orb-web spider

description: 1. In animals, behavioural responses may play an important role in
 determining population persistence in the face of environmental changes.
 Body size is a key trait central to many life history traits and
 behaviours. Correlations with body size may constrain behavioural
 variation in response to environmental changes, especially when size
 itself is influenced by environmental conditions. 2. Urbanization is an
 important human-induced rapid environmental change that imposes multiple
 selection pressures on both body size and (size-constrained) behaviour.
 How these combine to shape behavioural responses of urban-dwelling species
 is unclear. 3. Using web-building, an easily quantifiable behaviour linked
 to body size, and the garden spider Araneus diadematus as a model, we
 evaluated direct behavioural responses to urbanization and body size
 constraints across a network of 63 selected populations differing in
 urbanization intensity. We additionally studied urbanization at two
 spatial scales to account for some environmental pressures varying across
 scales and to obtain first qualitative insights about the role of
 plasticity and genetic selection. 4. Spiders were smaller in highly
 urbanized sites (local scale only), in line with expectations based on
 reduced prey biomass availability and the Urban Heat Island effect. Web
 surface and mesh width decreased with urbanization at the local scale,
 while web surface also increased with urbanization at the landscape scale.
 The latter two responses are expected to compensate, at least in part, for
 reduced prey biomass availability in cities. The use of multivariate mixed
 modelling reveals that although web traits and body size are correlated
 within populations, behavioural responses to urbanization do not appear to
 be constrained by size: there is no evidence of size-web correlations
 among populations or among landscapes, and web traits appear independent
 from each other. 5. Our results demonstrate that responses in
 size-dependent behaviours may be decoupled from size changes, thereby
 allowing fitness maximisation in novel environments. The spatial scale at
 which traits respond suggests contributions of both genetic adaptation
 (for web investment) and plasticity (for mesh width). Although fecundity
 decreased with local-scale urbanization, Araneus diadematus abundances
 were similar across urbanization gradients; behavioural responses thus
 appear overall successful at the population level.
description: R Script to reproduce
 analysesThis file allows to
 reproduce analyses presented in the paper using the three datasets made
 available alongside it.Dahirel_et_al_2018_JAnimEcol_Rcode.RSpider web and body size informationThis file contains trait information for all spiders included in the Journal of Animal Ecology paper. See README for details.individual_spider_info.txtLandscape-level urbanizationThis file contains levels of urbanization for all 3 by 3 km landscapes included in the Journal of Animal Ecology paper. See README for details.landscape_urbanization_info.txtSpider population densityThis file contains spider population density (females caught per 200*200 m site) for all sites included in the Journal of Animal Ecology paper. See README for details.population_densities_info.txt