Mating

Corixidae can attract a mate using "stridulation", where they rub their front legs against their head, a strigil on their abdomen or by rubbing their front wings together. This created a high pitched squeaking or chirping sound. The appear to have two calls during the mating season, one for courtship and one for aggregation.

Photo Aquarius najas

Egg Laying

Female water bugs generally lay eggs in or on vegetation and also on hard surfaces like stones, both singular or in clusters. This can be in spring or autumn and for some both as they can have 2 generations a year. There are between 10 and 1000 eggs depending on species and also food availability. They generally take 1 to 2 weeks to hatch

Photo Hydrometra stagnorum nymph

Nymphs/Larvae

The nymphs come out after the eggs are hatched. Nymphs somewhat look similar to the adult but lack wings. Some look as though they have wings but they are not used. It goes through five intermediate stages to form instars by the process of molting. When the larvae/adult emerge they are in a teneral state which means they are often soft and pale until they fully develop and harden. The nymphs are difficult to identify to species as the full species have not been developed yet.

Photo by Calum McLennan

Nepa cinerea nymph

Hydrometridae

Eggs are laid singly and attached at right angles to stems (Sometimes stones) at or above water level. The eggs split vertically at eclosion - there is an egg burster - and the larvae emerge to walk, during the first instar at least, with the shortened abdomen carried erect. Old adults live on into July whilst new adults , after a larval life of at least 3 weeks, appear from early June onwards. (Swammerdam and De Geer)

Photo Hydrometra stagnorum nymph by Mike Averill

Gerridae

Overwintered adults appear and lay eggs from late March to May. They are laid at the water line but if above water and dry out then can fail to hatch. They take between 10 and 19 days to hatch. They can have 1 or two generations a year usually again in August to September. The second generation can be apterous or macropterus. The nymphs generally take between 20 and 30 days to mature to an adult. (Southwood and Leston)

Photo mating Gerris sp. by Graham Hunt

Nepidae

Mating takes place from early April to late May with the male lying obliquely across and above the female grasping her with his front legs. Ovipsition happens at dusk soon after and the eggs are inserted within masses of green filamentous algae or in the stems and leaves of water plants immeadiately beneath the water line. Egg development can take between 3 to 6 weeks and the larval stage between 6 and 8 weeks. Some adults may also overwinter but usually are infertile.

Photo Nepa cinerea eggs by Keara Giannotti

Notonectidae

Mating occurs between December and late may but the oviposition season is mainly from early February to early May. Oviposition is spread over some weeks and 8 batches of 8 eggs are laid. They are all oval, elongate and embedded lengthwise in plant stems. The five instars occupy at least 2 months but by early August larvae are outnumber by new adults. (Southwood and Leston)

Photo Notonecta nymph by Jim Logan

Corixini

Usually adults overwinter (as can eggs and larvae) and mating takes place from Late January to May. Two male strigilated calls are emainly emitted during the breeding season probably an aggregation song and a courtship song. Eggs and larvae take about 2 to 4 months for full development and the next generation lay eggs in Mid to late July and adult from September. Hesperocorixa are not known to strigilate. (Southwood and Leston)

Photo Corixid nymph by Jim Millard

Nepidae

Mating takes place from early April to late May with the male lying obliquely across and above the female grasping her with his front legs. Ovipsition happens at dusk soon after and the eggs are inserted within masses of green filamentous algae or in the stems and leaves of water plants immeadiately beneath the water line. Egg development can take between 3 to 6 weeks and the larval stage between 6 and 8 weeks. Some adults may also overwinter but usually are infertile. (Southwood and Leston)

Photo Nepa cinerea nymph by iain Perkins

Naucoridae

After overwintering as adults, the bugs mate from late February onwards. Oviposition mostly occurs between late April and the end of May, eggs being inserted in rows in stems of aquatic plants. Egg development takes about a month and the five larval instars a further 2 months. The old females live on for some time. (Southwood and Leston)

Photo Ilyocoris cimicoides nymphs by James Heal

Aphelocheiridae

They mostly overwinter as adults and mate and oviposit in late spring and through the summer. Eggs are fixed singly to stones and sometimes old mollusc shelss. Larvae are abundant in the later instars during August and September but the latter month are outnumbered by the new adults. (Southwood and Leston)

Photo Aphelocheirus aestivalis nymph by Nick Mott

Pleidae

This is a comparitively late bug. Overwintered adults mate in late June and July and oviposit mainly within the leaves of such plants as water milfoil and Water Crowfoot. Egg development may take up to 4 weeks and larval up to 7 weeks. By the beginning of September most of the years generation are adult. (Southwood and Leston)

Photo Plea minutissima

Veliidae

Eggs are laid loosely on moss in late May and early June. Old overwintered females outlive the males and can be found through most of june. Egg and larval development together take about 7 weeks and by late July some of the new generation are adult, the bulk being present by late august. Generally they have 1 generation a year but have been known to have 2. (Southwood and Leston)

Photo Velidae nymph