DOI: 10.5061/dryad.hqbzkh1hd
title: Data from: Evidence for morph-specific substrate choice in a green-brown polymorphic grasshopper

description: Orthopteran insects are characterized by high variability in body
 coloration, in particular featuring a widespread green-brown color
 polymorphism. The mechanisms that contribute to the maintenance of this
 apparently balanced polymorphism are not yet understood. To investigate
 whether morph-dependent microhabitat choice might contribute to the
 continued coexistence of multiple morphs, we studied substrate choice in
 the meadow grasshopper Pseudochorthippus parallelus. The meadow
 grasshopper occurs in multiple discrete, genetically determined color
 morphs that range from uniform brown to uniform green. We tested whether
 three common morphs preferentially choose differently colored backgrounds
 in an experimental arena. We found that a preference for green backgrounds
 was most pronounced in uniform green morphs. If differential choices
 improve morph-specific performance in natural habitats via crypsis and/or
 thermoregulatory benefits, they could help to equalize fitness differences
 among color morphs and potentially produce frequency-dependent
 microhabitat competition, though difference appear too small to serve as
 the only explanation. We also measured the reflectance of the grasshoppers
 and backgrounds and used visual modelling to quantify the detectability of
 the different morphs to a range of potential predators. Multiple potential
 predators, including birds and spiders, are predicted to distinguish
 between morphs chromatically, while other species, possibly including
 grasshoppers themselves, will perceive only differences in brightness. Our
 study provides the first evidence that morph-specific microhabitat choice
 might be relevant to the maintenance of the green-brown polymorphisms in
 grasshoppers and shows that visual distinctness of color morphs varies
 between perceivers.
description: There are three datasets: 1) Data on substrate
 choice has been collected by visual checks at irregular intervals. Date
 and time of recording are given in the file. Each row refers to a record
 of an individual at a specific point in time. Patch number and patch color
 are readouts. There are repeated measurements per individual and
 attributes of individuals (sex, color morph, developmental stage) are
 given. There are many missing values (indicated by NA) when an individual
 was still alive, but not sitting on the floor. 2) Data
 on patch temperatures. Records refer to temperature recordings of green
 and brown experimental substrates and are always paired (one green and one
 brown patch recorded). 3) Data on spectrometric
 reflectance measurements of grasshoppers and substrates (recorded by a
 hand-held spectrophotometer, AvaSpec-2048, Avantes). Data from the
 recording device has been compiled in a single table and rounded to 3
 digits. The data are somewhat oddly formatted, but are ready to be used
 for analysis by the pavo package in R. Each row refers to a wavelength
 (given in the first column) and all other columns refer to individual
 records (reflectance of a particular body part or substrate at a
 particular wavelength). Attributes of the record are encoded in the column
 header (see readme file for details).
description: There are readme files for all datasets. For the reflectance data
 there are five repeated measurements per patch (indicated by the last two
 digits of the column header) and these have later been averaged in the
 analysis. There are very few cases with fewer measurements.