Environmental Engineering Reference
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attracted to lights and swarm around them. Their
life cycle takes about 6 weeks from egg to adult.
4. Family: Gerridae, Leach, 1815
These are popularly known as “water striders”
or “pond skaters”. They are semiaquatic long-
legged hemipterans. These insects are found
skating or leaping about on the surface fi lm of
wetlands. When disturbed, they scatter widely in
all directions. They feed upon a number of micro-
crustaceans and insects that are caught just below
the water surface. The family is represented by
about 450 species in the world. The body is oval
shaped and covered with a velvety hydrofuge hair
pile. Both winged and nonwinged forms occur,
but the latter are more common (Thirumalai
1986). Adults are between 5/16 and 5/8 in. long,
dull to greyish or reddish brown above and sil-
very grey on the underside of the body. Many
have long slender bodies with long slender legs
and antennae. The front legs are short and modi-
fi ed for grasping, while the middle and hind legs
are long, like stilts with claws. These insects
creep on the surface of running water or pools in
a slow deliberate gait where they feed on live and
dead insects, crustacea and other organisms.
They overwinter as adults. Long, cylindrical eggs
are laid during spring and summer in parallel
rows glued to objects at the water's edge.
5. Family: Notonectidae
Notonectidae is a cosmopolitan family of
aquatic insects in the order Hemiptera, com-
monly called backswimmers because they swim
upside down. They are all predators, up to nearly
2 cm in size. They are similar in appearance to
Corixidae (water boatmen) but can be separated
by differences in their dorsal-ventral coloura-
tion, front legs and predatory behaviour. Their
dorsum is convex and lightly coloured without
cross striations. Their front tarsi are not scoop
shaped and their hind legs are fringed for swim-
ming. There are two subfamilies, Notonectidae
and Anisopinae, each containing four genera.
The most common genus of backswimmers is
Notonecta
- streamlined, deep-bodied bugs up to
16 mm long and green, brown or yellowish in
colour. As the common name indicates, these
aquatic insects swim on their backs, vigorously
paddling with their long, hair-fringed hind legs.
They inhabit still freshwater, e.g. lakes, pools
and marshes, and are sometimes found in garden
ponds. Although primarily aquatic, they can fl y
well and so can disperse easily to new habitats.
Adults are about 1/2 in. long and black and white
coloured, swim upside down on their backs and
have triangular-like (boat-shaped) bodies and
large eyes. They are kidney shaped, with a four-
segmented beak and antennae of three to four
segments concealed between the head and tho-
rax. There is an irregular brown and blackish
band across the wings at the base of the membra-
nous portion. The front and middle legs are fi tted
for grasping, while the hind legs are fl attened,
fringed and fi tted for swimming. They are often
seen on the water surface with their long hind
legs held straight out and pointed forward,
poised for a fast start. They live in all kinds of
water (fresh to scum-covered stagnant) and over-
winter as adults. They fl y long distances, often in
swarms, and are attracted to lights. The life cycle
requires about 40 days. They feed on insects,
tadpoles and small fi sh. They can bite, causing
pain much like a bee sting when handled
carelessly.
Order: Hemiptera
Suborder : Heteroptera
Infraorder: Nepomorpha, Popov, 1968
1. Family: Nepidae, Latreille, 1802
Subfamily: Ranatrinae, Latreille, 1802
Tribe: Ranatrini, Latreille, 1802
Genus:
Ranatra
, Fabricius, 1790
1 .
Ranatra elongata
, Fabricius, 1790
2 .
Ranatra fi liformis
, Fabricius, 1790
3 .
Ranatra digitata
, Hafi z & Pradhan, 1947
Subfamily: Nepinae,
Latreille, 1802
Tribe: Nepini, Latreille, 1802
Genus:
Laccotrephes
, Stal, 1866
4 .
Laccotrephes griseus
, Guerin-Meneville, 1844
5 .
Laccotrephes ruber
, Linnaeus, 1764
6 .
Laccotrephes elongatus
, Montandon, 1907
2. Family: Belostomatidae, Leach, 1815
Subfamily: Belostomatinae, Leach, 1833
Genus:
Diplonychus
, Laporte, 1833
7 .
Diplonychus rusticus
, Fabricius, 1781
8 .
Diplonychus annulatus
, Fabricius, 1781
Subfamily: Lethocerinaea, Lauck & Menke,
1961
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