Friday, March 10, 2017

Anyone seen a giant water bug in Greece?

The Giant Water Bug, Lethocerus patruelis (Stål, 1855), is a huge aquatic insect belonging to the family Belostomatidae. It is the only species of this family living in Europe, where it is known from the Balkans (Albania, Bulgaria, Croatia, Greece, FYROM, Montenegro, Romania, Serbia, Turkey) and perhaps Hungary (doubtful) (Polhemus 1995; Protić 1998; Perez Goodwyn 2006; Fent et al. 2011). It has only recently been recorded in Italy (Bacchi & Rizzotti Vlach 2005). It is said to have a "chorotype" restricted to the Indo-Mediterranean, with exclusion of North Africa and the W-Mediterranean (see Vigna Taglianti et al. 1999). (I guess chorotype refers to its natural biogeographical range....anyway...).

However, although I am not an expert - little is known about the bug in Greece.If anyone has any sightings of this species from Greece especially the south or the islands we would be interested.

My personal experience, as a bird and fish enthousiast (not an entomologist) is that they are commoner in the North of Greece (using ricefields, lowland wetland areas). I have seen them in Dadia, Evros (see photos below), Lyra (Evros) and once in the Kefallonia (a museum specimen in fact). I have friends who have seen them as far south as the Sperchios - where they may be common. Whatever the case, I think they are not abundant or even common in the southern half of the country. For many years for example in the Amvrakikos I did not see one (although I think it has been mentioned to exist there). Also I have never seen or know of anyone how has seen the species in small wetlands. It could be vulnerable to dessication of wetlands - who knows...

Anyway we should start treating bugs, fascinating bugs like this, as important biodiversity indicators - and people can participate.

As the cyberworld grows there are interesting citizen-support tools for identification and dissemination from amateurs see this:

Also as I was recently informed by Bulgarian scientists:

An article published in the open access journal Zookeys provides detailed information on karyotype, the chromosome behavior, and the male reproductive system of the largest European water insect Lethocerus patruelis. Interesting insights into the life habits and the distribution of the species on the Balkans are also presented. During the last ten years, there are many new records of this species in Southern Bulgaria, perhaps providing evidence that the giant water bug is expanding its territory northwards. Such a wide and abundant distribution of the species in these regions would be a further sign of the recent changes of European bug fauna caused by climate change and an important clue for the effects of global warming. For more information see: Grozeva, S. et al. (2013) Sex chromosome pre-reduction in male meiosis of Lethocerus patruelis (Stål, 1854) (Heteroptera, Belostomatidae) with some notes on the distribution of the species. ZooKeys 319 (Special issue: Advances in Hemipterology): 119-135 (doi: 10.3897/zookeys.319.4384)

One last thing: 
The East Asian closely related species is well known as an edible species in a number of different Southeast Asian cuisines. Internet sources say the insect tastes like scallops or shrimp.

Lethocerus patruelis in the village of Dadia, Evros (Northeastern Greece, Summer 2009).

Lethocerus patruelis as found by me under a streat light in the village of Dadia (Summer 2009).