DOI: 10.5061/dryad.tb2rbp0cg
title: Data from: Specialized flower visitation in montane butterflies is associated with positive population trajectories over time

description: Insect biodiversity is under threat from multiple stressors including
 climate change and extreme weather. For butterflies, nectar resource use
 is an understudied trait in relation to population trajectories and
 responses to global change. Here, we characterize nectar breadth for 50
 species of montane butterflies occurring in the Sierra Nevada mountains of
 California and Nevada. These species displayed a wide spectrum of nectar
 use including relative specialists and extreme generalists. Further, we
 examined how nectar breadth and other species traits, including latent
 variables indicating ecological flexibility and dispersal potential, were
 indicative of long-term population trajectories, and responses to an
 extreme drought event from 2011-2015. Species that were more
 nectar-generalized were more likely to be declining, but nectar breadth
 did not predict how a species responded to extreme drought. Greater
 ecological flexibility as reflected in other traits was positively
 associated with population performance, while dispersal potential was
 negatively associated with population trajectories. Drought response was
 strongly associated with flight period, where species that fly later in
 the season are more susceptible to negative effects of drought. Our study
 highlights the importance of considering butterfly nectar breadth in
 predicting population resilience, and challenges assumptions about dietary
 generalism as a buffer against environmental change.
description: # Data from: Specialized flower visitation in montane butterflies is
 associated with positive population trajectories over time
 [https://doi.org/10.5061/dryad.tb2rbp0cg](https://doi.org/10.5061/dryad.tb2rbp0cg) ## Description of the data and file structure The data used consists of data from photographic observations from the authors and iNaturalist data from GBIF, and nectar breadth values derived from those observations. Species-level trends are derived from long-term monitoring of Sierra butterflies started by Dr. Art Shapiro, and contributed to by the Forister lab.  ### Files and variables #### File: all_data_copy.csv **Description:** NA values in the data represent values of variables that were not available due to absent information, or insufficient information (i.e., rarefied nectar breadth was not calculated for species with fewer than 10 observations). ##### Variables * Butterfly: Butterfly species name * n: number observations, i.e. number of photographs containing species * trend: population trend coefficient, i.e. beta coefficient for each species both within each site and across all monitoring sites that represents the change in the probability of observation of the species throughout the time series. * drought: drought response, i.e. an index of how a species performed pre- and post- drought (including drought years).  * rare: rarefied nectar breadth; estimated nectar breadth values for each species using rarefaction to a common sample size of 10.  * range: geographic range of a given species in meters squared * wingspan: average wing span of a species in millimeters  * mean_dlf: mean date of last flight for a species, given by Julian date   * larva_plt: number larval host plant species, count * abun: index of abundance, i.e. species-level index of abundance calculated as the average number of days a species was observed at each site, out of the number of days the site was visited from 2014-2022, and averaged across sites * weed: affinity for weedy habitat, binary (0 = not associated with weedy habitat, 1 = associated with weedy habitat)  #### File: plant_fam_sub.csv **Description:**  ##### Variables * SpScott: Butterfly species * n: number plant families butterfly found on  #### File: "pht_rare.csv" **Description:** Contains abundance matrix where the row names are the butterfly species, column names are the plant species, and cell value contains the number of occurances of that butterfly on that plant #### ## Code/software #### File: revised_analysis_and_figs.R **Description:** Contains all code for statistical analysis and figure creation. All scripts were written and run using R (version 4.2.3).