title: Higher mobility of butterflies than moths connected to habitat suitability and body size in a release experiment.
abstract: Mobility is a key factor determining lepidopteran species responses to environmental change. However, direct multispecies comparisons of mobility are rare and empirical comparisons between butterflies and moths have not been previously conducted. Here, we compared mobility between butterflies and diurnal moths and studied species traits affecting butterfly mobility. We experimentally marked and released 2011 butterfly and 2367 moth individuals belonging to 32 and 28 species, respectively, in a 25 m × 25 m release area within an 11-ha, 8-year-old set-aside field. Distance moved and emigration rate from the release habitat were recorded by species. The release experiment produced directly comparable mobility data in 18 butterfly and 9 moth species with almost 500 individuals recaptured. Butterflies were found more mobile than geometroid moths in terms of both distance moved (mean 315 m vs. 63 m, respectively) and emigration rate (mean 54% vs. 17%, respectively). Release habitat suitability had a strong effect on emigration rate and distance moved, because butterflies tended to leave the set-aside, if it was not suitable for breeding. In addition, emigration rate and distance moved increased significantly with increasing body size. When phylogenetic relatedness among species was included in the analyses, the significant effect of body size disappeared, but habitat suitability remained significant for distance moved. The higher mobility of butterflies than geometroid moths can largely be explained by morphological differences, as butterflies are more robust fliers. The important role of release habitat suitability in butterfly mobility was expected, but seems not to have been empirically documented before. The observed positive correlation between butterfly size and mobility is in agreement with our previous findings on butterfly colonization speed in a long-term set-aside experiment and recent meta-analyses on butterfly mobility.
authors.affiliation: Finnish Environment Institute, Natural Environment Centre P.O. Box 140, FI-00251, Helsinki, Finland.
authors.forename: Mikko
authors.initials: M
authors.lastname: Kuussaari
authors.affiliation: Castréninkatu 10 b 17 FI-00530, Helsinki, Finland.
authors.forename: Matias
authors.initials: M
authors.lastname: Saarinen
authors.affiliation: Finnish Environment Institute, Natural Environment Centre P.O. Box 140, FI-00251, Helsinki, Finland.
authors.forename: Eeva-Liisa
authors.initials: EL
authors.lastname: Korpela
authors.affiliation: Finnish Environment Institute, Natural Environment Centre P.O. Box 140, FI-00251, Helsinki, Finland.
authors.forename: Juha
authors.initials: J
authors.lastname: Pöyry
authors.affiliation: MTT Agrifood Research Finland, Plant Production Research FI-31600, Jokioinen, Finland.
authors.forename: Terho
authors.initials: T
authors.lastname: Hyvönen
keywords: Animal movement; dispersal propensity; experimental study on migration; habitat preference; interspecific differences in mobility; mark-release-recapture study; release habitat suitability; species traits; variation in dispersal ability; wingspan