DOI: 10.5061/dryad.c2fqz618t
title: In search of an honest butterfly: Sexually selected wing coloration and reproductive traits from wild populations of the Cabbage White Butterfly

description: Abstract Sexual selection is central to many theories on mate selection
 and individual behavior. Relatively little is known, however, about the
 impacts that human-induced rapid environmental change are having on
 secondary sexually selected characteristics. Honest signals function as an
 indicator of mate quality when there are differences in nutrient
 acquisition and are thus potentially sensitive to anthropogenically
 altered nutrient inputs. We used the cabbage white butterfly, Pieris rapae
 (L.) (Lepidoptera: Pieridae), to investigate differences in color and
 testes size in a system that is often exposed to agricultural landscapes
 with nitrogen addition. We collected individuals from four sites in
 California and Nevada to investigate variation in key traits and the
 possibility that any relationship between wing color and a reproductive
 trait (testes size) could vary among locations in the focal butterfly.
 Coloration variables and testes size were positively albeit weakly
 associated across sites, consistent with the hypothesis that females could
 use nitrogen-based coloration in the cabbage white as an indicator for a
 male mating trait that has the potential to confer elevated mating success
 in progeny. However, variation in testes size and in the relationship
 between testes size and wing color suggest complexities that need
 exploration, including the possibility that the signal is not of equal
 value in all populations. Thus these results advance our understanding of
 complex relationships among environmental change and sexual selection in
 the wild.
description: Individual butterflies were collected from four
 different wild population sites in northern Nevada and northern California
 (“Site”). Wing reflectance data for male individuals were calculated from
 raw spectra data and summarized in the data set provided. These variables
 (R50, LR50, and BR50) were calculated as described in Morehouse, N. I.,
 & Rutowski, R. L. (2010), Tigreros (2013) and Espeset et al.
 (2019). Wing lengths were measured using imageJ software, and testes
 weights were dissected from male individuals and weighed. Spermatophores
 were dissected and counted from females. Data was used in multiple linear
 models using R v.3.5.1.
 Morehouse, N. I., & Rutowski, R. L. (2010).
 In the eyes of the beholders: Female choice and avian predation risk
 associated with an exaggerated male butterfly color. <i>American
 Naturalist</i>, <i>176</i>(6), 768–784.
 https://doi.org/10.1086/657043
 Tigreros, N. (2013). Linking nutrition and sexual
 selection across life stages in a model butterfly system.
 <i>Functional Ecology</i>, <i>27</i>(1), 145–154.
 https://doi.org/10.1111/1365-2435.12006
 Espeset, A., Kobiela, M. E., Sikkink, K. L., Pan, T.,
 Roy, C., & Snell-Rood, E. C. (2019). Anthropogenic increases in
 nutrients alter sexual selection dynamics: A case study in butterflies.
 <i>Behavioral Ecology</i>, <i>30</i>(3), 598–608.
 https://doi.org/10.1093/beheco/arz004
description: Each variable, unit measurement, and any pertinent information
 about variables are explained in the README file. More information about
 the calculation of the colorimetric variables can be found above (Methods)
 and in the associated manuscript.