Characterizing the adult and larval transcriptome of the multicolored Asian lady beetle, Harmonia axyridis.

Lindsay A Havens,Matthew D Macmanes

doi:10.7717/peerj.2098

Abstract

The reasons for the evolution and maintenance of striking visual phenotypes are as widespread as the species that display these phenotypes. While study systems such as Heliconius and Dendrobatidae have been well characterized and provide critical information about the evolution of these traits, a breadth of new study systems, in which the phenotype of interest can be easily manipulated and quantified, are essential for gaining a more general understanding of these specific evolutionary processes. One such model is the multicolored Asian lady beetle, Harmonia axyridis, which displays significant elytral spot and color polymorphism. Using transcriptome data from two life stages, adult and larva, we characterize the transcriptome, thereby laying a foundation for further analysis and identification of the genes responsible for the continual maintenance of spot variation in H. axyridis.

Highlights

The evolution and maintenance of phenotypic polymorphism and striking visual phenotypes have fascinated scientists for many years (Darwin, 1859; Endler, 1986; Fisher, 1930; Gray & McKinnon, 2007; Joron et al, 2006)
Harmonia axyridis, provides a unique opportunity to explore the genetic basis behind the maintenance of an easy to quantify variation—elytral spot number
While understanding these genomic mechanisms is beyond the scope of this paper, we do provide a reference transcriptome for H. axyridis, a foundational resource for this work

Summary

Introduction

The evolution and maintenance of phenotypic polymorphism and striking visual phenotypes have fascinated scientists for many years (Darwin, 1859; Endler, 1986; Fisher, 1930; Gray & McKinnon, 2007; Joron et al, 2006). Insects have become increasingly popular as study organisms to examine phenotypic variation (Jennings, 2011; Joron et al, 2006). One such insect displaying extensive elytra and spot variation that has yet to be extensively studied is the Asian Multicolored Ladybeetle, Harmonia axyridis. Aposematism, crypsis, and mimicry may play a role in the evolution of phenotypic variation in the animal kingdom. A mimicry strategy is utilized by one well-characterized species that exhibits phenotypic polymorphism, the Neotropic butterfly system, Heliconius. The color, pattern, and eyespot polymorphism seen in Heliconius is thought to have arose as a result of Müllerian mimicry (Flanagan et al, 2004) and the supergenes underlying these traits have been well characterized (Kronforst et al, 2006; Joron et al, 2006; Jones et al, 2012)

Methods

Results

Conclusion