No evidence for differential survival or predation between sympatric color morphs of an aposematic poison frog

Abstract

Because variation in warning signals slows down the predator education process, aposematic theory predicts that animal warning signals should be monomorphic. Yet, warning color polytypisms are not uncommon in aposematic species. In cases where warning signal variants are separated geographically, adaptation to local predators could explain this variation. However, this cannot explain the persistence of sympatric polymorphisms in aposematic taxa. The strawberry poison frog (Oophaga pumilio) exhibits both allopatric and sympatric warning color variation in and around the Bocas del Toro archipelago of Panama. One explanation that has been proposed for the rapid diversification of O. pumilio coloration in this archipelago is low predation; if island populations have few predators, stabilizing selection would be relaxed opening the door for diversification via selection or genetic drift. Using a combination of mark-recapture and clay model studies, we tested for differences in survival and predation among sympatric red and yellow color morphs of O. pumilio from Bastimentos Island. We found no evidence for differential survival or predation in this population, despite the fact that one morph (red) is more common and widely distributed than the other (yellow). Even in an area of the island where the yellow morph is not found, predator attack rates were similar among morphs. Visual modeling suggests that yellow and red morphs are distinguishable and conspicuous against a variety of backgrounds and by viewers with different visual systems. Our results suggest that general avoidance by predators of red and yellow, both of which are typical warning colors used throughout the animal kingdom, may be contributing to the apparent stability of this polymorphism.Electronic supplementary material The online version of this article

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

“…However, not all studies conducted on poison frogs have found evidence for positive FDS. Two recent studies of predation on polytypic and polymorphic populations of Oophaga pumilio did not find evidence that positive FDS was involved in maintaining color differences in two populations (Hegna et al 2013b, Richards-Zawacki et al 2013). However, additional investigation would be needed across the geographic distribution of Oophaga pumilio where nearly 20 polytypic morphs occur to fully understand if positive FDS maintains differences in some locations (Hegna et al 2013b).…”

“…My work in concert with that of Nokelainen (2013) raises the question whether greater predator generalization might permit increased warning signal variation in northern areas, but much additional behavioral work is needed to probe the question. At the same time, recent evidence in some poison frog systems (Richards-Zawacki et al 2013, Amézquita et al 2013) and from examining a number of aposematic taxa (Alice Exnerová and Pavel Štys, personal communication) may lead to a conclusion that generalization occurs to a higher degree in the tropics than previously thought. An empirical finding that any latitudinal behavioral differences in generalization behavior exist would be illuminating in discussions of biogeographic patterns of diversity (see also Ricklefs 2009).…”

“…Sexual selection is also thought to play a role in the intra-specific diversification of warning signals in the strawberry poison frog (Oophaga pumilio) (Rudh et al 2011, Cummings & Crothers 2013. Although it is well established that females prefer color morphs that are similar to their own coloration (Summers et al 1999, Maan & Cummings 2008, recent work has shown that predators may not select for local morphs on the basis of color alone (Hegna et al 2013b, Richards-Zawacki et al 2013. Instead, base coloration of O. pumilio may be related to their toxicity (Maan & Cummings 2012).…”

Temporal relationship between genetic and warning signal variation in the aposematic wood tiger moth (Parasemia plantaginis)

“…; Richards‐Zawacki et al . ) and are also used by females to distinguish local males, which are preferred (Maan & Cummings ). Similarly, some warning signals in lepidopterans are jointly involved with mate choice (Nokelainen et al .…”

Reproductive isolation related to mimetic divergence in the poison frog Ranitomeya imitator

“…A number of species display remarkable intraspecific diversity in colourpattern [19][20][21][22] , although in most cases the source of divergent selection among populations is unclear [23][24][25][26][27] . In Ranitomeya imitator, intraspecific divergence in colour-pattern is associated with selection for Müllerian mimicry 28 , which led to the establishment of four distinct mimetic morphs of this species in central Peru 29 .…”