DOI: 10.5061/dryad.hmgqnk9j0
title: Data from: Continuous variation in an aposematic pattern affects background contrast, but is not associated with differences in microhabitat use

description: Variation in aposematic signals was once predicted to be rare, yet in
 recent years it has become increasingly well-documented. Despite increases
 in the frequency with which polytypism and polymorphism have been
 suggested to occur, population-wide variance is rarely quantified. We
 comprehensively sampled a subpopulation of the poison frog Oophaga
 sylvatica, a species which is polytypic across its distribution and also
 shows considerable within-population polymorphism. On one hand, color
 pattern polymorphism could be the result of multifarious selection acting
 to balance different signaling functions and leading to the evolution of
 discrete sub-morphs which occupy different fitness peaks. Alternatively,
 variance could simply be due to relaxed selection, where variation would
 be predicted to be continuous. We used visual modeling of conspecific and
 heterospecific observers to quantify the extent of within-population
 phenotypic variation and assess whether this variation produced distinct
 signals. We found that, despite considerable color pattern variation,
 variance could not be partitioned into distinct groups, but rather all
 viewers would be likely to perceive variation as continuous. Similarly, we
 found no evidence that frog color pattern contrast was either enhanced or
 diminished in the frogs’ chosen microhabitats compared to alternative
 patches in which conspecifics were observed. Within population phenotypic
 variance therefore does not seem to be indicative of strong selection
 towards multiple signaling strategies, but rather pattern divergence has
 likely arisen due to weak purifying selection, or neutral processes, on a
 signal that is highly salient to both conspecifics and predators.
description: In March 2020, we photographed 35 <em>Oophaga sylvatica </em>(Perla morph) at the private forest reserve ‘Bosque Protector la Perla’ near La Concordia, Ecuador. This represented a comprehensive survey of every individual observed in the area by a team of five experienced observers, over two days. The Perla morph is approximately 26 mm in length and is predominantly black with a red pattern that varies from small spots to larger irregular blotches, to whole patches of homogenous color. Previous work suggests that the frogs' colors have very high internal and external contrast, and that UV reflectance is minimal both from the frogs and their natural leaf litter background (Yeager and Barnett 2020). We photographed each frog within the microhabitat where it was first observed, following methods detailed in Yeager and Barnett (2020), Yeager and Barnett (2021). In brief, each image was taken using a quartz converted UV sensitive Canon EOS 7D camera combined with a metal body NIKKOR EL 80 mm lens. As UV reflectance is negligible in this population (Yeager and Barnett 2020) we did not include UV wavelengths and only utilized images in the human visible range (400 – 700 nm). The camera was mounted on a tripod and the lens was fitted with a Baader UV-IR blocking filter that allowed transmission from 420 - 680 nm. All photographs were taken under natural ambient lighting, each image included a 10% and a 77% neutral reflectance standard, and we saved all photographs in RAW format.
description: # Data from: Continuous variation in an aposematic pattern affects
 background contrast, but is not associated with differences in
 microhabitat use Data used
 in: Yeager & Barnett.\ Can continuous variation in a polymorphic
 aposematic signal represent an adaptive benefit?\ Justin Yeager &
 James B. Barnett For further information contact: Justin Yeager\ Email:
 ## Description of the data and file structure
 ### ## ==== INTERNAL CONTRAST DATA - K-MEANS & CLUSTER ANALYSIS ====
 Data files: * 01_InternalContrast_Bird.txt internal chromatic &
 achromatic contrast, & pattern energy from the blue tit (bird) visual
 model * 02_InternalContrast_Snake.txt internal chromatic & achromatic
 contrast, & pattern energy from the coachwhip (snake) visual model *
 03_InternalContrast_Frog.txt internal chromatic & achromatic contrast,
 & pattern energy from the O. pumilio (frog) visual model Format:
 tab-delimited text Column identification: * visual_model: BlueTit (bird),
 Masticophis (snake), or Opumilio (frog) * species: frog species
 (Osylvatica) * location: location where frog was encountered (Perla) *
 lighting: light spectrum used in visual modelling (D65) * frog_ROI: ROI
 from which data was extracted (whole_frog) * frog_ID: unique code for each
 frog * int_col: chromatic contrast between red and black regions of the
 frog pattern (ΔS = hue) * int_lum: achromatic contrast between red and
 black regions of the frog pattern (ΔL = luminance) * patt_016: pattern
 energy at 16 px (0.5 mm) * patt_032: pattern energy at 32 px (1.0 mm) *
 patt_064: pattern energy at 64 px (2.0 mm) * patt_128: pattern energy at
 128 px (4.0 mm) * patt_256: pattern energy at 256 px (8.0 mm) ### ## ====
 EXTERNAL CONTRAST DATA - BACKGROUND COLOR & PATTERN MATCHING ==== #\#
 Data files: * 04_ExternalContrast_Bird.txt: external chromatic, achromatic
 & pattern contrast between frogs and backgrounds from the blue tit
 (bird) visual model * 05_ExternalContrast_Snake.txt: external chromatic,
 achromatic & pattern contrast between frogs and backgrounds from the
 coachwhip (snake) visual model * 06_ExternalContrast_Frog.txt: external
 chromatic, achromatic & pattern contrast between frogs and backgrounds
 from the O. pumilio (frog) visual model Format: tab-delimited text Column
 identification: * visual_model: BlueTit (bird), Masticophis (snake), or
 Opumilio (frog) * species: frog species (Osylvatica) * location: location
 where frog was encountered (Perla) * lighting: lighting spectrum used in
 visual modelling (D65) * frog_ROI: ROI from which data was extracted
 (whole_frog) * frog_ID: unique code for each frog * background_type:
 microhabitat comparison (local = where frog was found, alternate = where
 other frogs were found) * background_ID: unique code for each background *
 JND_col: chromatic contrast between the mean frog and mean background (ΔS
 = hue) * JND_lum: achromatic contrast between the mean frog and mean
 background (ΔL = luminance) * ABC_pat: pattern contrast between the whole
 frog and the whole background (ABC = area between pattern energy curves)
 \## ==== Thank you for your interest in our data ==== ##