Sympatric occurrence of three leaf beetle species of Macroplea Samouelle, 1819 (Coleoptera, Chrysomelidae, Donaciinae) in Finland with a key to species in Northern Europe

ABSTRACT

Macroplea Samouelle, 1819 is the only known fully aquatic leaf beetle genus with three European species that have earlier been classified by their assumed water salinity preferences. We studied the inter- and intraspecific variation of the specimens living in Northern Europe using both molecular (cytochrome c oxidase subunit I, COI) and morphological evidence. The variation in the COI sequences between M. mutica (Fabricius, 1792) and M. pubipennis (Reuter, 1875) was 8.4%–9%, M. mutica and M. appendiculata (Panzer, 1794) – 3.9%–4.9%, and M. appendiculata and M. pubipennis – 8.8%–9.2%. All three species were sampled together in the Bothnian Sea on the same water plants, showing that neither salinity nor plant species bear a decisive importance in their occurrence in the region. Phylogenetic results suggest the existence of two currently unknown Macroplea species that are evolutionarily close to M. appendiculata. A key to the Nordic species is provided.

KEYWORDS:

• Coleoptera
• Chrysomelidae
• Donacinae
• Macroplea
• COI
• phylogeny
• key to species
• Northern Europe

Acknowledgements

We wish to thank Gunilla Ståhls-Mäkelä and Elvira Rättel for their help in laboratory work as well as Jaakko Haapamäki and Charlotta Björklund for their help in the field. Tapani Hopkins kindly checked the language. We wish to thank two anonymous referees for their valuable comments on the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was funded by the Academy of Finland (Kari M. Kaunisto); the Ella and Georg Ehrnrooth Foundation (Kari M. Kaunisto); VARELY (Rami Laaksonen, Suvi Kiviluoto); and the Ministry of the Environment (Rami Laaksonen, Suvi Kiviluoto).