In the UK we have traditionally used the names ‘Lesser’ and ‘Greater’ water boatmen to describe many of our swimming water bugs.
To make life simpler, many biologists now call greater water boatmen ‘backswimmers’ because this is the most obvious difference between the two groups, and saves confusion. Lesser water boatmen swim on their fronts, and greater water boatmen – backswimmers – swim on their backs. Added to this the tiny Lesser Backswimmer Plea leachii is smaller than virtually all other ‘lesser’ water boatmen. Lesser Water Boatmen, which all look rather like each other, are technically members of just one family of animals, the Corixidae. The backswimmers comprise two families in Britain, the Notonectidae and, for the Lesser Backswimmers, the Pleidae.
Although approximately half of the species of water bug recorded from ponds are different kinds of Lesser Water Boatmen, their sheer variety is sometimes not appreciated because they do all look quite similar. For those interested in developing their wildlife identification skills, Lesser Water Boatmen are good place to start – once you get your microscope or hand lens eye in they have some nice easy characters to distinguish them. Water bugs aren’t just pond animals – rivers and streams may have backswimmers in the stiller, well-vegetated areas, and saucer bugs, water scorpions and occasionally water stick insects too.
Encouraging water bugs to your pond
Bugs are often very good fliers – so they’re usually some of the first creatures to arrive at new garden ponds. Watch your pond on a warm day and you will often see backswimmers taking off.
It is not difficult to attract Lesser Water boatmen and backswimmers to garden ponds: both the species of alkaline, base-rich water will turn up quickly. Whether the species typical of acid water, or the species of dense vegetation or bigger ponds can be attracted to garden ponds is less clear.
Water bugs of one kind or another should always be present in a good quality wildlife pond. They’re not particularly sensitive to pollution: some can live in the most apparently inhospitable ponds including those with lots of bare polluted sediments and with no water plants.
Please note: you must be careful if you catch a Greater Water boatman when pond dipping as they can give a nasty nip, which is painful but not poisonous