Variation in spectral reflectance among populations of Dendrobates pumilio, the strawberry poison frog, in the Bocas del Toro Archipelago, Panama

Abstract

Aim The goal of this study was to quantify levels of variation in spectral reflectance within and among populations of Dendrobates pumilio, the strawberry poison frog from the Bocas del Toro Archipelago. Location This study was carried out in the Bocas del Toro Archipelago, in the Republic of Panama, Central America. Methods Spectral reflectance was measured for samples of individuals from fifteen distinct island and mainland populations, using an Ocean Optics 2000 spectrometer and a BiLink portable computer. Results Our results provide quantitative evidence for extreme polymorphism among populations, and more limited levels of polymorphism within some populations. No obvious signs of sexual dimorphism were found. All the colour morphs appear to have relatively little reflectance in the ultraviolet part of the spectrum. There is some evidence for clinal variation in colour and pattern across some mainland populations. There is also at least one area where distinctly different morphs occur in sympatry, suggesting the possibility of incipient reproductive isolation. We argue that variation in coloration may have been enhanced by sexual selection.

Not all colors are equal: predation and color polytypism in the aposematic poison frog Oophaga pumilio

“…We were also able to visually compare the general shape of our reflectance curves to those reported in Summers et al (2003). Previous studies found that O. pumilio (Schmidt) do not reflect UV light (Summers et al 2003). Therefore, we verified that our clay mixtures and permanent marker used to create eyes did not reflect UV light.…”

“…We measured the color directly from the color chart, compared it with each clay mixture, and adjusted the mixtures accordingly. We were also able to visually compare the general shape of our reflectance curves to those reported in Summers et al (2003). Previous studies found that O. pumilio (Schmidt) do not reflect UV light (Summers et al 2003).…”

“…However, the close proximity of Isla Colón to other islands with red frogs (Almirante and Isla Cristobal see Fig. 1; also see Summers et al 2003;Siddiqi et al 2004) raises the possibility that some predators attacking O. pumilio have previously encountered red frogs. Although some species of birds may visit adjacent islands, others are less likely to move across water (pers.…”

“…Members of the genus Craugastor (Cope) are often brown in body color (Savage 2002). Studies of predation on poison frogs typically use visual comparisons to match colors (e.g., Saporito et al 2007b;Noonan and Comeault 2009;Chouteau and Angers 2012) because dendrobatid coloration mostly lacks UV reflectance, which makes by-sight comparisons easier (Noonan and Comeault 2009; see also Summers et al 2003). However, we attempted to improve upon these methods to better ensure frog model color accuracy.…”

Influences of geographic differentiation in the forewing warning signal of the wood tiger moth in Alaska

“…Some of the species found to have geographically varying warning signals include Neotropical Heliconius butterflies (Brown & Benson 1974, Brower 1996, Mallet 2010, ladybird beetles (Creed 1966, Brakefield 1985, Dolenská et al 2009, Blount et al 2012, monarch butterflies (Brower 1958, Davis et al 2005, Davis et al 2012, newts (Mochida 2009, Mochida 2011, poison frogs (Daly & Myers 1967, Savage 1968, Summers et al 2003, Wang & Summers 2010, Wang 2011, Rudh et al 2011, Maan & Cummings 2012, Willink et al 2013, RichardsZawacki et al 2013, Hegna et al 2013b), velvet ants (Wilson et al 2012), alpine leaf beetles (Borer et al 2010), and bumble bees (Plowright & Owen 1980). Interestingly, some aposematic species appear to switch between aposematic and cryptic strategies across their distributions.…”