Distribution of aquatic true bugs (Hemiptera: Heteroptera: Nepomorpha) in Bulgaria

We present an overview of 861 published and 575 new records of the Nepomorpha species from 519 localities in Bulgaria. The new records are based on the material collected from 232 localities between 2005 and 2020. There are 41 species from 17 genera and nine families of Nepomorpha reported for Bulgaria. Among them, Micronecta minutissima (Linnaeus, 1758), Sigara scripta (Rambur, 1840) and Hesperocorixa moesta (Fieber, 1848) require confirmation due to insufficient data on their occurrence in the country. We also studied the distribution of Nepomorpha species in the main basins of Bulgaria and made a comparison with the water bug assemblages of neighbouring countries. Most of the localities were classified into habitat types according to the EUNIS classification. The potential associations between species and specific habitat types were explored. Ten of the species showed statistically significant positive associations with a particular habitat type. The summarised here data revealed that the Nepomorpha species composition of the mountainous habitats in Bulgaria is significantly less well studied (very few reported localities) than that of the lowland habitats. Therefore, future studies focused on aquatic habitats at altitude above 1000 m are advisable.