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

Daniela H Palmer,Marcus R Kronforst,Adriana D Briscoe,Susan D Finkbeiner,Antónia Monteiro,Yue Qian Tan

doi:10.1002/ece3.4207

Daniela H Palmer, Marcus R Kronforst + Show 4 more

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https://doi.org/10.1002/ece3.4207

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Abstract

The swallowtail butterfly Papilio polytes is known for its striking resemblance in wing pattern to the toxic butterfly Pachliopta aristolochiae and is a focal system for the study of mimicry evolution. Papilio polytes females are polymorphic in wing pattern, with mimetic and nonmimetic forms, while males are monomorphic and nonmimetic. Past work invokes selection for mimicry as the driving force behind wing pattern evolution in P. polytes. However, the mimetic relationship between P. polytes and P. aristolochiae is not well understood. In order to test the mimicry hypothesis, we constructed paper replicas of mimetic and nonmimetic P. polytes and P. aristolochiae, placed them in their natural habitat, and measured bird predation on replicas. In initial trials with stationary replicas and plasticine bodies, overall predation was low and we found no differences in predation between replica types. In later trials with replicas mounted on springs and with live mealworms standing in for the butterfly's body, we found less predation on mimetic P. polytes replicas compared to nonmimetic P. polytes replicas, consistent with the predator avoidance benefits of mimicry. While our results are mixed, they generally lend support to the mimicry hypothesis as well as the idea that behavioral differences between the sexes contributed to the evolution of sexually dimorphic mimicry.

Highlights

Mimicry is a classic example of evolution by natural selection. Bates (1862) noted the resemblance between sympatric but distantly related butterfly species, some of which were unpalatable to predators and some of which were palatable
Analyses of flight kinematics suggest that mimicry extends beyond wing patterning to behavioral similarity between P. polytes and P. aristolochiae in wing movements and flight path (Kitamura & Imafuku, 2010, 2015). These studies are highly suggestive of an adaptive resemblance between mimetic P. polytes and P. aristolochiae resulting in predator avoidance, but there exist no direct tests of Batesian mimicry using natural populations of these species and free-ranging bird predators
While we did find a larger number of attacks on nonmimetic female P. polytes compared to mimetic P. polytes, consistent with the expectations of Batesian mimicry, we found that P. aristolochiae replicas experienced the most attacks and nonmimetic males the fewest attacks

Summary

| INTRODUCTION

Mimicry is a classic example of evolution by natural selection. Bates (1862) noted the resemblance between sympatric but distantly related butterfly species, some of which were unpalatable to predators. Analyses of flight kinematics suggest that mimicry extends beyond wing patterning to behavioral similarity between P. polytes and P. aristolochiae in wing movements and flight path (Kitamura & Imafuku, 2010, 2015) Taken together, these studies are highly suggestive of an adaptive resemblance between mimetic P. polytes and P. aristolochiae resulting in predator avoidance, but there exist no direct tests of Batesian mimicry using natural populations of these species and free-ranging bird predators. We directly assayed bird predation rates based on attack marks or the loss of a bait and tested for differential predation among the sexes and morphs of P. polytes in comparison with P. aristolochiae in order to analyze the selective advantage of mimicry

| MATERIALS AND METHODS

Findings

| DISCUSSION