Batesian-Müllerian mimicry ring around the Oriental hornet (Vespa orientalis)

Abstract

Mimicry is usually understood to be an adaptive resemblance between phylogenetically distant groups of species. In this study, we focus on Batesian and Müllerian mimicry, which are often viewed as a continuum rather than distinct phenomena, forming so-called Batesian-Müllerian mimicry rings. Despite potent defence and wide environmental niche of hornets, little attention has been paid to them as potential models in mimicry research. We propose a Batesian-Müllerian mimicry ring of the Oriental hornet (Vespa orientalis, Hymenoptera: Vespidae) consisting of eight species that coexist in the Mediterranean region. To reveal general ecological patterns, we reviewed their geographical distribution, phenology, and natural history. In accordance with the ‘model-first’ theory, Batesian mimics of this ring occurred later during a season than the Müllerian mimics. In the case of Batesian mimic Volucella zonaria (Diptera: Syrphidae), we presume that temperature-driven range expansion could lead to allopatry with its model, and, potentially, less accurate resemblance to an alternative model, the European hornet (Vespa crabro: Hymenoptera: Vespidae). Colour morphs of polymorphic species Cryptocheilus alternatus (Hymenoptera: Vespidae), Delta unguiculatum (Hymenoptera: Vespidae), Rhynchium oculatum (Hymenoptera: Vespidae), and Scolia erythrocephala (Hymenoptera: Scoliidae) appear to display distinct geographical distribution patterns, and this is possibly driven by sympatry with alternative models from the European hornet (Vespa crabro) complex. General coevolution patterns of models and mimics in heterogenous and temporally dynamic environments are discussed, based on observations of the proposed Oriental hornet mimicry ring.