Environmental Engineering Reference
In-Depth Information
Genus:
Lethocerus
, Mayr, 1853
9 .
Lethocerus indicus
, Lepeletier & Serville,
1852
3. Family: Notonectidae, Latreille, 1802
Subfamily: Anisopinae, Hutchinson, 1929
Genus:
Anisops
, Spinola, 1837
10. Anisops bouvieri, Kirkaldy, 1904
11. Anisops sardeus sardeus, Herrich-Schaffer,
1850
4. Family: Corixidae, Leach, 1815
Subfamily: Micronectinae, Leach, 1815
Genus:
Micronecta
, Kirkaldy, 1897
12.
Micronecta scutellaris scutellaris
, Stal, 1858
Infraorder: Gerromorpha, Popov, 1971
5. Family: Gerridae, Leach, 1815
Subfamily: Gerrinae, Bianchi, 1896
Genus:
Limnogonus
, Stal, 1868
13.
Limnogonus (Limnogonus) nitidus
,
the least explored families (Jach and Balke
(
2008
)).
Of the more than one million described spe-
cies of insects, at least one-third is beetles, mak-
ing the Coleoptera the most diverse order of
living organisms. The order Coleoptera (beetles)
is the largest order of insects. It belongs to the
infraclass Neoptera and division Endopterygota.
Members of this order have an anterior pair of
wings (the
elytra
) that are hard and leathery and
not used in fl ight; the membranous hindwings,
which are used for fl ight, are concealed under the
elytra when the animals are at rest. Only 10 % of
the 350,000 described species of beetles are
aquatic. Aquatic species occur in two major sub-
orders: the Adephaga and the Polyphaga. Both
larvae and adults of six beetle families are
aquatic: Dytiscidae (predaceous diving beetles),
Elmidae (riffl e beetles), Gyrinidae (whirligig
beetles), Haliplidae (crawling water beetles),
Hydrophilidae (water scavenger beetles) and
Noteridae (burrowing water beetles). Five fami-
lies, Chrysomelidae (leaf beetles), Limnichidae
(marsh-loving beetles), Psephenidae (water pen-
nies), Ptilodactylidae (toe-winged beetles) and
Scirtidae (marsh beetles), have aquatic larvae and
terrestrial adults, as do most of the other orders of
aquatic insects; adult limnichids, however, read-
ily submerge when disturbed. Three families
have species that are terrestrial as larvae and
aquatic as adults, Curculionidae (weevils),
Dryopidae (long-toed water beetles) and
Hydraenidae (moss beetles), a highly unusual
combination among insects.
Beetles are holometabolous. Eggs of aquatic
coleopterans hatch in 1 or 2 weeks, with diapause
occurring rarely. Larvae undergo from 3 to 8
moults. The pupal phase of all coleopterans is
technically terrestrial, making this life stage of
beetles the only one that has not successfully
invaded the aquatic habitat. A few species have
diapausing prepupae, but the most complete
transformation to adults ensues in 2 to 3 weeks.
Terrestrial adults of aquatic beetles are typically
short-lived and sometimes nonfeeding, like those
of the other orders of aquatic insects.
Unlike the Hemiptera, the larvae of Coleoptera
are morphologically and behaviourally different
Mayr,
1865
Genus:
Limnometra
, Mayr, 1865
14.
Limnometra fl uviorum
, Fabricius, 1798
More than 275 species of Hemiptera are
known from India, but only 14 species of
Hemiptera belonging to 5 families are reported
from the lakes of Hyderabad.
Coleoptera
The order Coleoptera, or beetles, is represented
by some 3,50,000 known species (Lawrence
1982
), but recent estimates suggest there are
hundreds of thousands or even millions of
undescribed species. Although the vast major-
ity of beetles are terrestrial, it is estimated that
about 18,000 species of aquatic Coleoptera are
present on the earth at present. About 12,600
(70 %) of these are already described. About
30 beetle families have aquatic representatives,
and in 25 of these families, at least 50 % of the
species are to be considered as aquatic. Six
families are supposed to include 1,000 or more
aquatic species: Dytiscidae (3,908 described
species/5,000 estimated), Hydraenidae
(1,380/2,500), Hydrophilidae (1,800/2,320),
Elmidae (1,330/1,850), Scirtidae (900/1,700)
and Gyrinidae (750/1,000). Scirtidae and
Hydraenidae and Haliplidae are regarded as
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