The detectability of the colour pattern in the aposematic firebug, Pyrrhocoris apterus: an image-based experiment with human 'predators'

T Bohlin, G Gamberale-Stille, Sami Merilaita, A Exnerova, P Stys, BS Tullberg

    Research output: Contribution to journalArticleScientificpeer-review

    21 Citations (Scopus)


    Crypsis and aposematism are often regarded as two opposite protective strategies. However, there is large variation in prey appearance within both strategies. In this article, we investigated the conspicuousness of the aposematic red-and-black firebug, Pyrrhocoris apterus, by presenting images of natural and digitally manipulated phenotypes in their natural habitat on a computer screen to human predators, and comparing the detection times. We asked whether the natural colour pattern can be made more or less conspicuous by rearranging the spatial distribution of colour elements. Hence, we created a phenotype in which the black colour elements were moved to the body outline to test for a possible disruptive effect. In the black and red manipulations, we removed one of the two colours, creating two uniform colour variants. We found that some of our manipulations increased, but none reduced, the detection time significantly; this indicates that the naturally coloured firebug is highly conspicuous. The detection time varied among backgrounds and there was a significant relationship between detection time and chromatic similarity between the bug and the background for the natural and black phenotypes. Although background colour composition has an important effect on the signal, we argue that the coloration of P. apterus has evolved for high conspicuousness.
    Original languageUndefined/Unknown
    Pages (from-to)806–816
    Number of pages11
    JournalBiological Journal of the Linnean Society
    Issue number4
    Publication statusPublished - 2012
    MoE publication typeA1 Journal article-refereed


    • aposematism
    • crypsis
    • distance dependent
    • human subjects
    • natural backgrounds
    • predation
    • prey coloration
    • warning coloration

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