First report of European Giant Water Bug preying on frogs

Giant Water Bug

It is a report that overturns the perception that Giant Water Bug prey on small fish and frogs.A record of a frog predation by Lethocerus patruelis, the only Giant Water Bug in Europe, has been published.The Giant Water Bug in Europe seems to eat very few frogs.

* The picture at the beginning is a Japanese Giant Water Bug, not a European Giant Water Bug.

A records of the Giant Water Bug (Lethocerus patruelis) inhabiting The Balkans preying on the frog Pelophylax kurtmuelleri have been published

Giant Water Bug is a predator that catch vertebrates such as fish, turtles, snakes and frogs with their large forelegs. The genus Lethocerus often preys on frogs, but no such cases have been confirmed in Europe (surprising!).

In this case, an adult Giant Water Bug (Lethocerus patruelis) preyed on frogs was recorded during a frog survey in a rice field in central Greece in August 2021. The temperature is 33 degrees celsius and the water temperature is 23.5 degrees, and the climate is close to summer in Japan.

Reference:Predation of the Balkan frogPelophylax kurtmuelleri (Gayda, 1940) (Anura: Ranidae) by the giant water bug Lethocerus patruelis(Stål, 1854) (Heteroptera: Belostomatidae)

World Giant Water Bugs and European Giant Water Bugs

The family Heteroptera: Belostomatidae is a carnivorous aquatic beetle, including the world’s largest aquatic insect. Among them, the Giant Water Bug subfamily (subfamily Lethocerinae) is divided into three generas, Benacus and Kirkaldyi and Lethocerus, which are known to prefer vertebrates as bait at each stage of growth. Specifically, in addition to larvae of fish and amphibians, records of preying on turtles and snakes are also recorded.

The genus southeast asian Giant Water Bug (Genus Lethocerus) is divided into 22 species, many of which live in the tropics, subtropical and temperate zones. Lethocerus patruelis, the only Giant Water Bug living in Europe, is the largest aquatic insect in Europe.

Lethocerus patruelis live mainly in the Balkans (Albania, Bosnia, Bulgaria, Croatia, Montenegro, Romania, and Serbia) and have recently been reported from Italy. Lethocerus patruelis is found throughout Greece and often in estuarine deltas and areas with slow currents.

Many species of Giant Water Bug are distributed in the Americas, as there are only one species in Europe and only two species in Asia: Japanese Giant Water Bug (Kirkaldyia deyrolli) and Taiwang Giant Water Bug (Lethocerus indicus).

European Giant Water Bug (Features of Lethocerus patruelis)

Summary so far. The fact that this is the first record seems to indicate that the European Giant Water Bug does not eat frogs as its main food source.

Lethocerus patruelis looks like it has features common in the genus Lethocerus, with a body length of 6-7 cm for males and 7-8 cm for females, almost the same physique as The Lethocerus indicus, which has a large population in Southeast Asia.

The distribution of Lethocerus patruelis is wide from the Balkans to India and Myanmar. According to the example of a Bulgarian study, it seems to be attracting attention that it is moving northward from the Balkans recently.

According to the observation records of Lethocerus patruelis in iNaturalist, it seems to inhabit mainly the southern coast of the Balkan Peninsula.

Distribution of Lethocerus patruelis in iNaturalist


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