Notonecta glauca
In 3 days ~10% in a week ~20%
Notonecta glauca, also known as the greater water-boatman or common backswimmer, is a species of aquatic insect in the family Notonectidae. This species is found in large parts of Europe, North Africa, and east through Asia to Siberia and China. In much of its range it is the most common backswimmer species. It is also the most widespread and abundant of the four British water-boatmen. Notonecta glauca are Hemiptera (true bug) predators, that are approximately 13–16 mm in length. Females have a larger body size compared to males. These water insects swim and rest on their back (hence their common name "backswimmer" or "water boatman") and are found under the water surface. Notonecta glauca supports itself under the water surface by using their front legs and mid legs and the back end of its abdomen and rest them on the water surface; They are able to stay under the water surface by water tension, also known as the air-water interface (surface tension). They use the hind legs as oars; these legs are fringed with hair and, when at rest, are extended laterally like a pair of sculls in a boat. Notonecta glauca will either wait for its prey to pass by or will swim and actively hunt its prey. When the weather is warm, usually in the late summer and autumn, they will fly between ponds. Notonecta glauca reproduce in the spring. Wikipedia →
| # | Park | Country | Daily sighting probability |
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More parks will be added in future updates.
Rare
Under 5% of wildlife watchers report a Eurasian Greater Water Boatman sighting in London on a given day, based on 18 verified sightings from GBIF citizen-science data. It is the 873rd most-seen of the 1504 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 20%, if each day is a fresh chance.
February
In that month about 10% of wildlife watchers report a Eurasian Greater Water Boatman in London on a given day, against under 5% in March to January, the lowest months.
3rd of 5
Of the 5 cities where we can rate Eurasian Greater Water Boatman sightings, London ranks 3rd at under 5%. The best odds are in Kyiv (Ukraine, about 10%) and Munich (Germany, under 5%).
Same order: Hemiptera
The closest relatives of the Eurasian Greater Water Boatman that you can see in London (order Hemiptera, True Bugs, Hoppers, Aphids, and allies) are Green Shield Bug (about 30%), Trivial Plant Bug (about 30%) and Dock Bug (about 20%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Eurasian Greater Water Boatman is recorded against all the insects logged in London (18 verified sightings), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
