Mechanisms of color production in a highly variable shield-back stinkbug, Tectocoris diopthalmus (Heteroptera: Scutelleridae), and why it matters

Scott A. Fabricant, Darrell J. Kemp, Jan Krajíček, Zuzana Bosáková, Marie E. Herberstein

Research output: Contribution to journalArticle

17 Citations (Scopus)
17 Downloads (Pure)

Abstract

Theory suggests that aposematism, specifically the learned avoidance of unprofitable prey via memorable color patterns, should result in selection for pattern uniformity. However, many examples to the contrary are seen in nature. Conversely, honest sexual signals are likely to exhibit greater variation because they reflect underlying variation in mate quality. Here we aim to characterize and quantify the mechanistic causes of color in Tectocoris diopthalmus to shed light on the costs of color production, and thus the potential information content of its color signals. We use Tectocoris diopthalmus because it is a weakly-defended stinkbug, and presents elements that have classically been studied in the context of aposematism (red coloring), and sexual selection (sexual dichromatism and iridescent coloring). Pigment analysis reveals that variation in orange coloration is due to the amount of erythropterin pigment, stored in intracellular granules. This pigment is common in Heteroptera, and as an endogenously produced excretory byproduct is unlikely to reflect mate quality or variation in unprofitability of the bug. Electron microscopy reveals the iridescent patches are caused by an epicuticular multilayer reflector, and the hue and patch size are directly related to the layer widths and extent of coverage of this layering. Furthermore, we identified melanin as an essential component of the multilayer reflector system; therefore, the quality of the iridescent patches may be affected by aspects of rearing environment and immunocompetence. We posit that T. diopthalmus has co-opted the melanic patches of a 'typical' red and black aposematic signal, transforming it into a complex and variable iridescent signal that may enhance its capacity to display individual quality.

Original languageEnglish
Article numbere64082
Pages (from-to)1-9
Number of pages9
JournalPLoS ONE
Volume8
Issue number5
DOIs
Publication statusPublished - 7 May 2013

Bibliographical note

Copyright the Author(s) 2013. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

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