Research Article |
Corresponding author: Antonín Hlaváček ( antonin.hlavacek69@gmail.com ) Academic editor: Michael Ohl
© 2022 Antonín Hlaváček, Klára Daňková, Daniel Benda, Petr Bogusch, Jiří Hadrava.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Hlaváček A, Daňková K, Benda D, Bogusch P, Hadrava J (2022) Batesian-Müllerian mimicry ring around the Oriental hornet (Vespa orientalis). Journal of Hymenoptera Research 92: 211-228. https://doi.org/10.3897/jhr.92.81380
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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.
biogeography, Conopidae, Diptera, evolution of mimicry, Hymenoptera, phenology, polymorphism, Syrphidae
Mimicry is an example of convergent evolution whereby similar appearances result in an evolutionary advantage, such as reduced risk of predation. Various defences in animals were described; however, most discussed are Batesian (
Although traditionally viewed as a parasitic interaction, Batesian mimicry could be beneficial to the defended model under certain circumstances, as it could decrease the error costs caused by a forgetful predator; this phenomenon is called quasi-Müllerian mimicry (
In various mimicry complexes we can find Batesian mimics, which resemble their models rather imperfectly (
The phenology of mimicry complexes can range from models and mimics occurring at the same time (temporal sympatry), models occurring first, or mimics occurring first in a season. Mathematical modelling (
Mimics face increased predation when they occur outside the geographic range of their models (
Here, we focus on the Batesian-Müllerian mimicry ring around the Oriental hornet (Vespa orientalis), a large and conspicuous social wasp occurring in Mediterranean, Southwest Asia, Central Asia and Northeast Africa. We identified seven species from various families of hymenopterans and dipterans that are likely Müllerian and Batesian mimics of Vespa orientalis. In the present paper, the information on ecology and biogeography of the Vespa orientalis mimicry ring are summarised and the following questions are addressed: 1) Which phenological pattern applies to the proposed mimicry ring (model first; mimic first; temporal sympatry)? 2) Are the mimics of the Oriental hornet (Vespa orientalis) sympatric with their model across their whole distribution area? 3) Is there spatial overlap between the mimicry rings of the Oriental hornet (Vespa orientalis) and the European hornet (Vespa crabro)?
We observed the mimicry ring around the Vespa orientalis on the Aegean island of Lesvos (Greece), from 27. viii. to 17. ix. 2019. We explored various habitats (chestnut forest, steppes, salt marshes, macchia) on the island (Fig.
Lesvos Island and collecting sites. From top: map of the Aegean Sea with Lesvos island highlighted; shrubland near the town of Petra, and shrubland in the western part of the island, typical habitat of species from Vespa orientalis complex. Letters refer to localities listed in the species list.
Species from Vespa orientalis mimicry ring observed on Lesvos. Letters refer to localities, displayed in Fig.
Species | Collecting sites, date and recorded specimens |
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Vespa orientalis L. 1771 | A: Achladeri, 39°9.42277'N, 26°17.04810'E, 29.8.2019, 1♀, C: Molivos, 39°21.09045'N, 26°10.42042'E, 2.9.2019, 1 ♂.Widely distributed and abundant species throughout the island. |
Rhynchium oculatum (F. 1781) | C: Molivos, Petrified forest, 39°21.09045'N, 26°10.42042'E, 2.9.2019, 1 ♂, H: Anaxos Skoutarou, 39°18.98855'N, 26°8.74678'E, 2.9.2019, 1 ♂ and 1♀, I: Petra, 39°19.34400'N, 26°9.94130'E, 2.9.2019, 2 ♂, G: Skala Eresou, 39°8.20328'N, 25°55.88838'E, 12.9.2019, 1♀, E: Agiasos, 39°4.82558'N, 26°22.11272'E, 13.9.2019. 1 ♂ |
Cryptocheilus alternatus (Lepeletier, 1845) | B: Kalloni, Moni Leimonos, 39°14.76615'N, 26°10.34943'E, 30.8.2019, 1♀, C: Molivos, 39°21.09045'N, 26°10.42042'E, 2.9.2019, 1♀. Collected on Foeniculum vulgare Mill. |
Delta unguiculatum (Villers, 1789) | C: Molivos, Petrified forest, 39°21.09045'N, 26°10.42042'E, 2.9.2019, 1 ♂. Collected on Foeniculum vulgare Mill., near a road. |
Conops flavicaudus (Bigot, 1880) | A: Achladeri, 39°9.42278'N, 26°17.04810'E, 29.8.2019, 1 ♂, A: Achladeri, 39°9.27038'N, 26°16.88825'E, 29.8.2019, 1♀ Collected on shrubs in an olive orchard near the coast. Several specimens were observed at this spot, but nowhere else on the island. |
Volucella zonaria (Poda, 1761) | E: Agiasos, 39°4.82558'N, 26°22.11272'E, 4.9.2019, 1♀, E: Agiasos, 39°4.82558'N, 26°22.11272'E, 13.9.2019, 2♀. Collected on Hedera helix L., suburbs, apple orchard. |
Milesia crabroniformis (F. 1775) | D: Agiasos. 39°3.31245'N, 26°23.91593'E, 5.9.2019, 1 ♀, E: Agiasos, 39°4.79915'N, 26°22.25362'E, 6.9.2019, 2 ♂ and 1 ♀, F: Agiasos, 39°6.08465'N, 26°21.27432'E, 15.9.2019, 1♀. Collected on Hedera helix L., suburbs, orchard. |
We searched for species with similar colouration pattern occurring in the Mediterranean area. Based on these criteria, we included Scolia erythrocephala F. 1775. However, we presume that the Vespa orientalis mimicry ring is probably much larger in the eastern (Asian) part of its distribution and might include species such as Delta pyriforme (F. 1775), Laphria dizonias Loew, 1864, Monoceromyia eumenioides (Saunders, 1842), Rhodanthidium superbum (Radoszkowski, 1876), Scolia flaviceps Eversmann, 1846 (present in Asia Minor, with some records from Greece and Turkey), or Stiphrolamyra pleskei (Becker, 1913). Nevertheless, those species were omitted due to the lack of data and will be explored in further studies.
We classified the species into Müllerian and Batesian mimicry groups. The Müllerian group was represented by five species of hymenopterans (Cryptocheilus alternatus, Delta unguiculatum, Scolia erythrocephala, Vespa orientalis, and Rhynchium oculatum). The Batesian group was represented by three species of dipterans (Conops flavicaudus, Milesia crabroniformis, and Volucella zonaria).
Information on the distribution, phenology, and habitat preferences were adopted from Syrph the Net databases for hoverflies (Speight 2016), from single faunistic records and studies for hymenopterans (
We compared the Vespa orientalis and its Batesian mimic Volucella zonaria to the mimetic pair of two related species, the European hornet (Vespa crabro) and its mimic Volucella inanis (L. 1758).
Other potential mimics of the European hornet (e.g. Asilus crabroniformis L. 1758, Cimbex connatus (Schrank 1776), queens of Dolichovespula media (Retzius 1783), or Volucella elegans Loew, 1862) are neither displayed nor analysed, as it lies beyond the scope of this paper.
Similarity of geographic distribution (counted as presence/absence within the country) was calculated for every model-mimic pair using Lennon’s index of similarity (
We reviewed the Batesian-Müllerian mimicry ring of eight species from various taxonomical and ecological groups: five species of hymenopterans in three families (Vespidae, Pompilidae, Scoliidae) forming the Müllerian part of the mimicry ring, and three Batesian mimics in two dipteran families (Conopidae, Syrphidae). Photographs, distribution maps, phenological charts and habitat preferences, compiled from previously published data, are presented in Fig.
The phenology of all species overlaps to some degree. Batesian mimics occur later (median of first occurrence: 7, mean of first occurrence: 6.75; counted in months) than their models (median of first occurrence: 3.5, mean of first occurrence: 4.17) corresponding with the ‘model first scenario’ (p-value = 0.04, Mann-Whitney test).
The distribution of species was reviewed (Fig.
Dendrogram showing similarity between species areas. Lennon’s index was used to calculate similarities, the dendrogram was created using UPGMA clustering. Yellow branch: species of Eastern Mediterranean, extending in Levant. Red branch: species present in the entire Ponto-Mediterranean area. Brown branch: Species that extended their range and are present even in central and northern Europe. Blue branch: Vespa crabro mimicry ring with Volucella inanis.
In the Oriental hornet mimicry ring, the Batesian mimics were found to occur later in the season than the Müllerian mimics. All species overlapped in the late summer. These results are consistent with the ‘model-first’ scenario (
Based on the analysis of geographic distribution, we assigned the species into three groups (‘branches’): Eastern Mediterranean branch (yellow in Fig.
We consider Vespa orientalis to be the ‘leading model’ of the studied mimicry ring.
Vespa orientalis is, in contrast with other Müllerian mimics in complex, habitat generalist, making it an ideal ‘leading model’. Unlike the other Müllerian mimics of the mimicry ring, Vespa orientalis is a social species, living in colonies which could number thousands of workers (
Colour polymorphism was described in some members of the mimicry ring. Interestingly, black morphs occurred sympatrically with the European hornet (Vespa crabro). Specifically, Batesian mimic Volucella zonaria sometimes tends to be darker with a black, ‘Vespa crabro-like’ pattern on the thoracic dorsum in some locations, i.e. in Corsica (van der Goot 1961), or the Czech Republic (personal observation). Dark colouration of the thorax and petiole was also observed in German populations of Müllerian mimic Delta unguiculatum (
An interesting case of colour polymorphism occurs in the Müllerian mimic Rhynchium oculatum. Three subspecies (sometimes considered as colour forms) of Rhynchium oculatum with slightly different colour pattern have been described (
Batesian mimic Volucella zonaria displays variable mimetic accuracy based on geographic location. We compared the Vespa orientalis and its Batesian mimic, hoverfly Volucella zonaria, with the related mimetic pair of the Vespa crabro and its mimic Volucella inanis. Although distribution areas of both mimetic pairs overlap, the area of Volucella inanis and Vespa crabro is shifted more northwards. However, Volucella zonaria undergoes annual migration to Central and Northern Europe and it is expanding northward in recent years (
In the last few decades a shift of geographic range has been observed in mimics (Volucella zonaria in
We characterized the Batesian-Müllerian mimicry ring of seven species around Vespa orientalis in the western Palearctic. Phenology, natural history, and the distribution of all species were reviewed. Previous studies on phenological patterns of mimics have provided ambivalent results; this study provides evidence that the Vespa orientalis mimicry ring fits the ‘model-first’ scenario. Review of distribution revealed differences in areas of species, forming Eastern Mediterranean, Mediterranean, and extending Mediterranean branches. We conclude that colour polymorphic species might resemble two different models (Vespa orientalis, Vespa crabro) across their distribution range. Moreover, we proposed that mimetic accuracy might vary across the distribution range of the migratory and expanding Batesian mimic Volucella zonaria, which seems to be a perfect mimic of Vespa orientalis, although an imperfect mimic of Vespa crabro.
Our results highlight the complexity of the proposed Batesian-Müllerian mimicry ring around the Oriental hornet (Vespa orientalis). Bringing the information on phenology, ecological strategy, colouration patterns and geographical distribution together is an approach that could deepen our understanding of the ecology and evolution of mimicry. We encourage the application of the eco-evolutionary approach to mimicry research, as it could help in further investigations of mimicry rings and explanation of phenomena such as the existence of imperfect mimicry.
We thank Tereza Hadravová for her help in the field and Tereza Fraňková for grammar and spell check. We would like to thank Dr. Brigitte Howarth and Dr. James Carpenter for their thoughtful comments and efforts towards improving our manuscript.
This project was supported by the Grant Agency of Charles University, projects no. 1030119/2019 and no. 464220/2020. The work of JH has been supported by Charles University Research Centre program No. 204069 and SVV260571/2022.
Data of distribution
Data type: excel file
Explanation note: Distribution data excerpted from literature.
Appendix 1
Data type: Species account (docx. file)
Explanation note: Natural history of species within Vespa orientalis mimicry ring.