DOI: 10.5061/dryad.4j0zpc89v
title: Microclimatic variability buffers butterfly populations against increased mortality caused by phenological asynchrony between larvae and their host plants

description: Climate change affects insects in several ways, including phenological
 shifts that may cause asynchrony between herbivore insects and their host
 plants. Insect larvae typically have limited movement capacity and are
 consequently dependent on the microhabitat conditions of their immediate
 surroundings. Based on intensive field monitoring over two springs and on
 larger-scale metapopulation-level survey over the same years, we used
 Bayesian spatial regression modelling to study the effects of weather and
 microclimatic field conditions on the development and survival of
 post-diapause larvae of the Glanville fritillary butterfly (Melitaea
 cinxia) on its northern range edge. Moreover, we assessed whether the
 observed variation in growth and survival in a spring characterized by
 exceptionally warm weather early in the season translated into population
 dynamic effects on the metapopulation scale. While similar weather
 conditions enhanced larval survival and growth rate in the spring,
 microclimatic conditions affected survival and growth contrastingly due to
 the phenological asynchrony between larvae and their host plants in
 microclimates that supported fastest growth. In the warmest microclimates,
 larvae reached temperatures over 20°C above ambient leading to increased
 feeding, which was not supported by the more slowly growing host plants.
 At the metapopulation level, population growth rate was highest in local
 populations with heterogeneous microhabitats. We demonstrate how
 exceptionally warm weather early in the spring caused a phenological
 asynchrony between butterfly larvae and their host plants. Choice of
 warmest microhabitats for oviposition is adaptive under predominant
 conditions, but it may become maladaptive if early spring temperatures
 rise. Such conditions may lead to larvae breaking diapause earlier without
 equally advancing host plant growth. Microclimatic variability within and
 among populations is likely to have a crucial buffering effect against
 climate change in many insects.
description: These datasets are a combination of fine-scale field monitoring
 data and metapopulation-level field survey data. Monitoring data consist
 of butterfly larval survival, growth, body surface temperature, and
 activity under variable weather and microclimatic conditions, as well as
 the growth of larval host plants under similar environmental conditions.
 For larval survival and growth, as well as host plant growth, the repeated
 measurements over the study season were averaged to gain a single value of
 each variable for each larval group and host plant plot. Larval
 temperature and activity datasets are time series with several
 measurements covering one day. Survey data consist of
 two separate datasets on local population growth rates from one autumn to
 the following under variable weather and microclimatic conditions.
 Microclimatic conditions were recorded separately for each larval group in
 the field and averaged for local populations. Rows with
 missing values were removed from all datasets.
description: Explanation of the variables can be found in the attached ReadMe
 file describing the dataset.