Prey from the eyes of predators: Color discriminability of aposematic and mimetic butterflies from an avian visual perspective

Abstract

Predation exerts strong selection on mimetic butterfly wing color patterns, which also serve other functions such as sexual selection. Therefore, specific selection pressures may affect the sexes and signal components differentially. We tested three predictions about the evolution of mimetic resemblance by comparing wing coloration of aposematic butterflies and their Batesian mimics: (a) females gain greater mimetic advantage than males and therefore are better mimics, (b) due to intersexual genetic correlations, sexually monomorphic mimics are better mimics than female-limited mimics, and (c) mimetic resemblance is better on the dorsal wing surface that is visible to predators in flight. Using a physiological model of avian color vision, we quantified mimetic resemblance from predators' perspective, which showed that female butterflies were better mimics than males. Mimetic resemblance in female-limited mimics was comparable to that in sexually monomorphic mimics, suggesting that intersexual genetic correlations did not constrain adaptive response to selection for female-limited mimicry. Mimetic resemblance on the ventral wing surface was better than that on the dorsal wing surface, implying stronger natural and sexual selection on ventral and dorsal surfaces, respectively. These results suggest that mimetic resemblance in butterfly mimicry rings has evolved under various selective pressures acting in a sex- and wing surface-specific manner.

Chemical Ecology of Poisonous Butterflies: Model or Mimic? A Paradox of Sexual Dimorphisms in Müllerian Mimicry

“…11.2). The female has been considered to be a Batesian mimic (Su et al 2015). The larvae feed on Violaceae plants similar to many other related species in the tribe Argynnini in Japan.…”

Experimental field tests of Batesian mimicry in the swallowtail butterfly Papilio polytes

“…Ohsaki (1995) proposed that females disproportionately benefit from evolving mimicry and indeed found that wild‐caught nonmimetic P. polytes females had nearly double the proportion of beak marks on their wings compared to P. polytes males (which are always nonmimetic). More recently, Su, Lim, and Kunte (2015) tested the mimetic resemblance of several sexually monomorphic and female‐limited Batesian mimics, including P. polytes , using bird vision models. Their results show that females are better mimics than males of sexually monomorphic taxa, and that female‐limited mimics are as good as sexually monomorphic mimics, supporting the idea that females disproportionately benefit from mimicry.…”

Does spatial variation in predation pressure modulate selection for aposematism?

“…Wallace (1866) introduced the idea of warning signaling (later termed aposematism) during his studies of butterflies in tropical Asia, but further use of tropical Asian butterflies for aposematism and mimicry studies has been extremely limited (Ex: Yamauchi, 1993; Kitamura & Imafuku, 2010; Kunte et al., 2014; Su et al., 2015). …”

“…Species possibly belonging to mimicry rings were separated based on (Kunte, 2008; Su et al., 2015), and additional regional species were added based on visual similarity and host plant information. These included five mimicry rings (names based on the most common aposematic genus of the ring); Danaus , Tirumala , Euploea (Danainae: Nymphalidae), Pachliopta (Papilionidae), and Delias (Pieridae).…”

“…For example, Danainae butterflies such as Monarch, Danaus plexippus , are well known for aposematism and their conspicuous warning signals. Nevertheless, African and Asian Danainae butterfly species vary tremendously in their color and conspicuousness (Su, Lim, & Kunte, 2015). …”