ARPHA Conference Abstracts : Conference Abstract
Conference Abstract
Phylogenetic diversity of water scorpions (Nepa spp., Insecta, Hemiptera)
expand article infoAndrei Ștefan‡,§, Jean-François Flot|, Elena Iulia Iorgu, Luis Ovidiu Popa, Steven L. Keffer, Fabio Stoch|, Șerban M. Sârbu§
‡ Grigore Antipa National Museum of Natural History, Bucharest, Romania
§ Emil Racoviță Institute of Speleology, Cluj-Napoca, Romania
| Université libre de Bruxelles, Bruxelles, Belgium
¶ James Madison University, Harrisonburg, VA, United States of America
Open Access


Water scorpions belonging to the genus Nepa are predatory freshwater aquatic insects of the order Hemiptera. There are currently five accepted species, with a Holarctic distribution: N. cinerea (Eurasia and Northern Africa), N. sardiniensis (Sardinia and Corsica), N. anophthalma (endemic to Movile Cave, Romania), N. apiculata (North America) and N. hoffmanni (Eastern Asia). Mitochondrial and nuclear genetic markers indicate a correlation between genetic diversity and geographic distribution. Analyses also reveal a cryptic diversity in the Western Mediterranean basin, with specimens of the cinerea clade being assigned to the sardiniensis clade. The cave-adapted N. anophthalma is genetically closest to N. cinerea, suggesting surface populations of N. cinerea as possible ancestors. N. cinerea samples from three cave systems in Italy indicate various degrees of gene flow between surface and subterranean populations and an instance of a possible incipient speciation event. Despite the overlap in distribution range in mainland Eastern Asia between N. cinerea and N. hoffmanni, there is a high genetic distance between the two species. A similar value of genetic distance is found between N. cinerea and N. apiculata, but also between N. hoffmanni and N. apiculata, suggesting the assignment of N. hoffmanni and N. apiculata to different genera. The single species currently considered as stygobiotic, N. anophthalma, deserves more research to understand the timing of colonization of Movile groundwater by its surface ancestors.


Nepa, Nepa anophthalma, water-scorpion, Movile Cave, cryptic diversity

Presenting author

Andrei Ștefan

Presented at

The 25th International Conference on Subterranean Biology (Cluj-Napoca, 18-22 July 2022)


The authors would like to thank the many colleagues and researchers that provided water scorpion specimens from all over their distribution range.

Funding program

This work was supported by a grant of the Romanian Ministry of Research and Innovation, CCCDI - UEFISCDI, project number PN-III-CEI-BIM-PBE-2020-0048 / 11 BM/2021, within PNCDI III (NEPA-GENSIZE); and by a grant of the Ministry of Research and Innovation (UEFISCDI) project number PN-III-P4-ID-PCE-2020-2843 (EVO-DEVO-CAVE).

Grant title

Genome size in a big world: can geographic distribution explain nuclear DNA content in water-scorpions (Nepa sp.)? - NEPA-GENSIZE

Convergent evolution, development and adaptations of crustaceans from chemosynthesis-based cave ecosystems (EVO-DEVO-CAVE)

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