STUDIES ON THE MOSQUITO FAUNA INHABITING SHORELINE HABITATS OF ORISSA COAST ( CULICIDAE : DIPTERA )

Mosquito fauna known from the world comprises 3,500 species that are tradionally classified in to three subfamilies viz. Anophelinae, Culicinae and Toxorhynchitinae under the family Culicidae of the Order Diptera. (Insecta). Taxanomic studies of the mosquito fauna of Indian subcontinent were extensively studied by Barraud (1934), Christophers (1933) and their monumental works led to Nagpal and Sharma (1995) updating 320 species of mosquitoes in 37 genera so far reported from India The mosquito fauna of Orissa state was studied by Fry (1912), Nagpal and Sharma (1983), Dash et al. (2000). However, Rajavel et al. (2005 a, b) has reported recently 74 species belonging to 12 genera and 20 subgenera from Jeypore Hill tracks of Orissa and 43 species belonging to 21 subgenera and 13 genera from mangroves of Bhiterkanika. Keeping in view of the prevalence of mosquito born diseases in Orissa, an attempt has been made here to document the diversity of mosquitoes inhabiting the shoreline habitats of south Orissa coast. The state of Orissa, the south eastern coastal state of India, is located between 17.49' Nand 22.34' Nand 81.27' E and 87.29' E (Fig. 1). It is bounded by the Bay of Bengal on the north east; Madhya Pradesh on the west and Andhra Pradesh on the south. The land area of the state covers 155,707 sq. kms. with a coast line of over 450 kms. On the basis of physiographical characteristics, the state has been divided into five major morphological regions viz. the Orissa Coastal Plain in the east, the Middle Mountainous and highlands, the Central plateaus, the Western rolling uplands and the major flood plains. The coastal belt of the state extends from the River S ubarnarekha near West Bengal border in the north to the River Rushikulya in the south near the border of Andhra Pradesh. Several deltas of varied sizes and shapes are formed by the major rivers of Orissa, such as the Subarnarekha, the Budhabalanga, the Baitarani, the Brahmani, the Mahanadi, and the Rushikulya. Therefore, the coastal plain of Orissa is also known as "Hexadeltaic Region" or the "Gift of Six Rivers". In addition, the largest brackish water lake of India, the Chilika is located between 85°20' E and 19°40' N, and is connected to the Bay of Bengal by a narrow channel 32 km long. These extensive river systems and the lakes are home of diverse faunal groups such as mosquitoes. that are adapted to survive in varied habitats like ponds, puddles, tree holes, swamps and salt marshes.


INTRODUCTION
Mosquito fauna known from the world comprises 3,500 species that are tradionally classified in to three subfamilies viz.Anophelinae, Culicinae and Toxorhynchitinae under the family Culicidae of the Order Diptera.(Insecta).Taxanomic studies of the mosquito fauna of Indian subcontinent were extensively studied by Barraud (1934), Christophers (1933) and their monumental works led to Nagpal and Sharma (1995) updating 320 species of mosquitoes in 37 genera so far reported from India The mosquito fauna of Orissa state was studied by Fry (1912), Nagpal and Sharma (1983), Dash et al. (2000).However, Rajavel et al. (2005 a, b) has reported recently 74 species belonging to 12 genera and 20 subgenera from Jeypore Hill tracks of Orissa and 43 species belonging to 21 subgenera and 13 genera from mangroves of Bhiterkanika.Keeping in view of the prevalence of mosquito born diseases in Orissa, an attempt has been made here to document the diversity of mosquitoes inhabiting the shoreline habitats of south Orissa coast.
The state of Orissa, the south eastern coastal state of India, is located between 17.49 ' Nand 22.34' Nand 81.27' E and 87.29' E (Fig. 1).It is bounded by the Bay of Bengal on the north east; Madhya Pradesh on the west and Andhra Pradesh on the south.The land area of the state covers 155,707 sq.kms.with a coast line of over 450 kms.On the basis of physiographical characteristics, the state has been divided into five major morphological regions viz. the Orissa Coastal Plain in the east, the Middle Mountainous and highlands, the Central plateaus, the Western rolling uplands and the major flood plains.The coastal belt of the state extends from the River S ubarnarekha near West Bengal border in the north to the River Rushikulya in the south near the border of Andhra Pradesh.
Several deltas of varied sizes and shapes are formed by the major rivers of Orissa, such as the Subarnarekha, the Budhabalanga, the Baitarani, the Brahmani, the Mahanadi, and the Rushikulya.Therefore, the coastal plain of Orissa is also known as "Hexadeltaic Region" or the "Gift of Six Rivers".In addition, the largest brackish water lake of India, the Chilika is located between 85°20' E and 19°40' N, and is connected to the Bay of Bengal by a narrow channel 32 km long.These extensive river systems and the lakes are home of diverse faunal groups such as mosquitoes.that are adapted to survive in varied habitats like ponds, puddles, tree holes, swamps and salt marshes.
A taxonomic account of 55 mosquito species under 12 genera, 17 subgenera and 3 tribes occurring in Puri and Khurda Districts of Orissa is presented in this study along with some observations on their ecology and distribution.The species of mosquitoes which are actually collected in the present survey marked with asterisk.

MATERIALS AND ME'IHODS
Two coastal districts of Orissa i.e., Khurda and Puri have been chosen for collection of mosquito samples.The Khurda and Puri districts are located 20° 40 'N and 85° 35'E and 19° 45'N and 85° 50'E respectively.Samples of adults and immature stages of mosquitos were collected from twelve villages around the Chilika Lake covering the two districts which represent diversified habitats.Random samplings were made during the period from January 2006 to September 2007 from different localities of Balugaon, Chhedapadar, Bidharpur, Pratap, Totapada villages in Khurda District and Alipara, Giqala, Sipakuda, Rambhartya Island, Ashram, Altunga, Beleswarpatna villages in Puri District (Fig. 1).
Mosquitoes were collected by employing simple standard techniques from indoor and outdoor habitats and from cattle sheds.Samples were also collected  during dawn and dusk while mosquitoes maximize their frequency of taking blood meal from the hosts.Mosquito repellant spray was used to paralyze the specimens.The knocked down specimens were collected by picking with the help of fine forceps and transfer them to the collection tubes to avoid breaking of legs.Suction tube was also used to collect the live mosquitoes.Resting adult mosquitoes were collected from the shrubs around the cattle sheds and human dwellings, paddy fields, and near by forest areas.Over 2000 examples of adults and immature stages of mosquitos have been collected by employing the above techniques during the survey period.Adults of male and female mosquitos and their immature stages were identified using standard literatures and the keys provided by Christopher, 1933;Barraud, 1934 andRao, 1984.In this study 22 species of mosquitoes belonging to 7 genera were identified from the south coastal Orissa.The diagnostic characters of all the species listed here are based on the key characters of adult females.Identified specimens were registered and deposited at the museum of Zoological Survey of India, Gopalpur, Orissa.

EXTERNAL FEATURES OF A MOSQUITO
The body of the mosquito is divided in to head, thorax, and abdomen (Fig. 2).The head (Fig. 3) contains compound eyes and proboscis.The proboscis is the piercing mouthparts used to "suck" blood from the victim.The mosquito's head is mostly formed of the compound eye.Each eye (Fig. 3) is made up of many tiny lenses forming a compound eye which allows for a broad field of vision.The thorax (Fig. 4) has one pair of wings (Fig. 7) and halteres.The abdomen (Fig. 5) or gut is capable of expanding as it ingests the prey's blood.The markings present on the thorax and abdomen are useful for the identification of the species.The length of mosquitoes varies in species but is rarely greater than 16 mm and weighs up to 2.5 mg.Mosquitoes are able to continuously fly for 1 to 4 hours at a speed of 1-2 kmph and travel up to 10 km in a night.Most species are nocturnal or crepuscular (dawn or evening) feeders.During the heat of the day most mosquitoes rest in a cool place and wait for the evening.The pathogens are transmitted to victims while sucking the blood.Diagnostic characters: palpi equal to the proboscis, completely dark and scales small in size; costa and subcosta are completely dark including vein 1 (Rl); prescuttelar space of thorax without setae; pale ring absent at the termination of tarsi.
Remarks : Breeds in a variety of places such as small pools and seepages, in the jungle tea garden drains which are shaded by tea plants, swamps, marshes, channels, river, rock pools, streams heavily shaded with trees, wells etc. Recorded from Mayurbhanj, Keonjhar and Koraput of Orissa.Diagnostic characters : Four banded palpi (tip of the palpi pale); Pale area on costa and subcosta including vein 1 (Rl) is less than 4, pale scale on inner costa and fringe spot on vein 5.2 (Cu2), basal dark mark on wing vein 5 (Cu) long (0.4 multiplied by length of Cu stem).Diagnostic characters : Apical pale band of palpi nearly equal to the pre-apical dark band; area at the bifurcation of wing vein 5 (Cu) dark; more than 3 pale area on costa and subcosta including vein 1 (Rl); speckling in fore and hind legs absent; tarsomeres 5, 4 and 3 of hind leg completely pale.Remarks: Mixed dwellings during day.Also found at outdoor in small numbers.Reported from Singhbhum, Chilika lake area, Puri, Keonjhar, Koraput of Orissa.

Anopheles (Cellia) culicifacies Giles*
1901.Anopheles culicifacies Giles, Entomologist's mono Mag.,37 : 198.Diagnostic characters : Apical pale band nearly equal to the preapical dark band of palpi; more than 3 Pale area on costa and subcosta including vein 1 (Rl); Fringe spot on vein 3 (R4 + 5) absent; speckling in fore and hind legs absent; hind tarsomeres 5, 4 and 3 are dark; bands on fore tarsomeres absent;.Diagnostic characters : Apical pale band nearly equal to the pre-apical dark band of palpi; wing with 4 or more dark spots on costa, involving costa and vein R, wing vein 3 (R4 + 5) and inner costa mostly pale and inner costa dark: speckling in legs absent; bands on fore tarsomeres absent.

Materials
Distribution: In India, occurs in all main lands.
Remarks: More percentage of adults rest at human habitats than cattle sheds in day time.The species also rests outdoors.Reported from Jeypore, Koraput, Mayurbhanj of Orissa.
Diagnostic characters : Pre-apical dark band l;.:i or 1/5 of the apical pale band of palpi; Wing with 4 or more dark spots on costa, involving costa and vein R, distance of the anterior forked cell from the base of the costa compared to that of posterior forked cell is small; speckling in legs absent; hind tarsomeres 5, 4 and 3 are dark; small bands on fore tarsomeres.
Remarks : Adults found largely in cattle sheds as well as inside houses.Found at altitudes from 2000 to 6000m.Reported from Jeypore hills of Orissa after which the species has been named.

Diagnostic characters:
Palpi with 4 pale-scaled bands.Wing with 4 or more dark spots on costa, involving costa and vein R, wing never all dark; only hindtarsomeres 5 and part of 4 pale-scaled.
Remarks: Reported all over Orissa.Breeds mainly in seepage.Not regarded as vector of Malaria.Res., 16 : 169.
Diagnostic characters: Apical and sub-apical pale band equal and separated by a small or same sized dark band intervening dark band of palpi; more than 4 Pale area on costa and subcosta including vein 1 (R1); speckling in fore and hind legs are absent; Hind leg tarsomeres 5, 4, and 3 are dark; tip of hind tarsomere pale and bands present on legs.
Distribution : In India it is found in Arunachal Pradesh, Assam, Goa, Karnataka, Kerala, Meghalaya, Mizoram, Orissa, Tamil N adu, Tripura and West Bengal.
Remarks: Breeds in grassy slow-running streams, breeding also recorded from open drains in tea gardens and fallow rice fields.Reported from Koraput, Orissa.Diagnostic characters : Apical and sub-apical pale band equal and separated by a small or same sized dark band intervening dark band of palpi; wing with 4 or more dark spots on costa, involving costa and vein R, inner costa interrupted; speckling in legs absent; Hind leg tarsomeres 5, 4, and 3 are dark; tip of hind tarsomere black and bands on legs absent.Diagnostic characters : Apical pale band nearly equal to the preapical dark band; more than 3 pale area on costa and subcosta including vein 1 (R1); speckling in fore and hind legs are absent; Hind leg tarsomeres 5,4, and 3 are dark; Band on foreleg tarsomeres are broad.Remarks: Breeds in stagnant waters, clear or turbid waters, water with or without vegetation, shaded or slightly shaded places, wells, burrow pits, channels, lake margins, ponds, tanks, ground pools, fallow and freshly flooded rice fields, cement cisterns, tree-holes, fresh or brackish waters.Recorded all over Orissa.
Diagnostic characters : Apical pale band nearly equal to the pre-apical dark band of palpi; pre-apical dark band 14 or 1/5 of the apical pale band; wing with 4 or more dark spots on costa, presence of fringe spot on vein 3 (R4 + 5)nvolving costa and vein R; speckling in legs absent; hind tarsomeres 5, 4 and 3 are dark; bands on fore tarsomeres absent.

Anopheles (Cellia) tessellates Theobald
Remarks : Reported all over Orissa, Occurring in mixed dwellings, cattle sheds and outdoors, rest particularly on the lower part of the walls.

Anopheles (Cellia) theobaldi Giles *
1901.Anopheles theobaldi Giles, Entomologist's.Mon. mag.,37 : 198.Diagnostic characters : More than 4 pale area on costa and subcosta including vein 1 (R1); speckling in fore and hind legs are present; Apical pale band of palpi nearly equal to the sub apical pale band; Hind tarsomeres only 5 and part of 4 pale; The dark band at 4th tarsomere of hind leg is absent.Distribution: Found all over India but concentrated mainly in central and western part of peninsula.
Remarks : Forest species and basically a stream breeder, also breeds in ponds, tanks, rice fields and riverbed pools.Reporeted all over Orissa.Diagnostic characters : Proboscis generally dark, sometime half of it is yellow; apical and sub-apical pale band equal and separated by same sized dark band intervening dark band of palpi; more than 4 Pale area on costa and subcosta including vein 1 (R1); inner costa of wing is dark; fringe spot absent on vein 6 (Anal); vein 5.1 (Cu 1) with two dark areas;speckling in fore and hind legs are absent; Hind tarsomeres 5, 4, and 3 are dark; Tip of hind tars om ere and bands on legs are black.Diagnostic characters : Black species, with snowwhite markings and white basal bands on tarsi, palpi, a narrow silvery-white median line running nearly whole length of mesonotum, scutellar scales flat and snowwhite on all lobes, wide white tarsal bands on 4th hind tarsal segment, line of flat silvery scales on border of mesonotum in front of wing root, white scales on pleurae in irregular patches, white transverse bands on abdomen at bases of segment.Remarks: It breeds in tree holes, bamboo, leafaxils.Only rarely in artificial receptacles or rock-pools.Recorded widely from all parts of Orissa.
Diagnostic characters : Palpi slender, upturned, without distinct hair-tufts; black species, with conspicuous snow-white ornamentation.mesonotum with several white patches; mid-femur with a median white spot on anterior surface.Distribution : Found throughout India.
Remarks : It breeds in tree hole, bamboo, forest floor etc. Recorded widely throughout the country.
Distribution : Found throughout India.
Remarks : It breeds in tree holes, bamboo, human landing.Reported from almost all states of India.Diagnostic characters: Black species, with snowwhite markings; proboscis with scattered yellow scaling ;mesonotum marked with 4-6 small white spots; femora with preapical white rings, and white basal bands on tarsi, all tibiae with white rings.
Distribution : Found throughout India.
Remarks: It breeds in tree hole, bamboo, leafaxils.Rock pools etc. Recorded through out the coastal belt of Orissa.

Aedes (Stegomyia) w-albus (Theobald)
1905.Stegomyia w-albus (Theobald) Annl.hist.nat.Mus.natn.hung., 3 : 74.Diagnostic characters : Palpi slender, upturned, without distinct hair-tufts; black species, with conspicuous snow-white ornamentation ; mesonotum with several white patches; mid-tarsi with a median white spot on anterior surface;.Distribution : Found throughout India.Diagnostic characters : The material has been identified only till genus level.It is a small mosquito with comparatively short legs, ornamented with a dense covering of white, black and yellow scales, tufts of suberect scales at tip and hind femora.Diagnostic characters : Proboscis and tarsi with pale rings (tarsal rings sometimes faint); no lower mesepimeral bristle; wings speckled with scales, which are usually numerous.
Distribution : Found throughout India.
Remarks: Breeds in Irrigation canal, ponds, ground pool, paddy field, slow-moving stream with algae.Recorded from all over Orissa especially from Bhitarkanika and Jeypore Hills.Diagnostic characters : Proboscis and tarsi with pale rings (tarsal rings sometimes faint); no lower mesepimeral bristle; abdominal tergites with distinct apical pale markings.

Culex (Culex) whitei Barraud
1923.Culex whitei Barraud,Indian. 1. med. Res.,11 : 508.Diagnostic characters: Very common small brown mosquito, with a pale band on the proboscis.Mesonotum with light and dark scales mixed in varying proportions, sometimes forming an indefinite pattern, but at least with light scales round front margin.
Distribution: It is mainly found in the north-eastern region of India though it is cosmopolitan in habit.
Remarks: It breeds in ground pools.Recorded From shorelines of Orissa.
Diagnostic characters : Proboscis and tarsi with pale rings (tarsal rings sometimes faint); no lower mesepimeral bristle; wings with broad scales on veins 1.3, and 5; mid an hind tibiae with pale lines.
Distribution: In India, occurs in all main lands.
Remarks : It breeds in ground pool, cement tank.Adults rested in vegetation.Recorded mainly from hilly areas of Orissa.
Genus Ficalbia Theobald Subgenus Ficalbia 46.Ficalbia (Ficalbia) minima (Theobald)   1901.Uranotaenia minima Theobald, Monogr.CuI., 2 : 262.Diagnostic characters : Mesonotum marked with distinct round spots of white scales, Yellowish brown; mesonotum marked with 4 (or more) distinct round white spots; rather broad white scales on mid-lobe of scutellum; Abdomen: lateral chitinous hooks on tergite VIII widely and evenly spaced, much as in indiana, but less curved.Diagnostic characters : Mesonotum not having so much distinct spots, Brownish-black; mesonotum marked with 2 (or 3) round white spots; scales on midlobe of scutellum narrow.Abdomen: Chitinous hooks on tergite VIII much as in M. uniformis, bur there is a more pronounced gap between the lateral and median series.Diagnostic characters : Mesonotum not having so much distinct spots; Mesonotum dark brown, not marked with greenish stripes; some white scales, tending to form indistinct spots or patches, in some specimens; Abdomen: Chitinous hooks on tergite VIII of female widely spaced and curved, without a definite gap between these and the median teeth.
Material examined : 10 exs (F) collected from Sipakuda, Puri Dist., I1.vi.2007, ColI. : S. Dash;Totapada, Khurda Dist., OS.vi.2007Diagnostic characters : Mesonotum not having so much distinct spots; Mesonotum marked with a pair of sub lateral greenish stripes on a brown ground; markings on tarsi as in annulifera but with yellowish tinge not snow-white; Abdomen : Lateral chitinous hooks on tergite VIII curved and slightly separated from median series.

DISCUSSION
The present study deals with 55 species of mosquitoes under 12 genera reported from coastal Orissa.Out of which over 2000 specimens belonging to 22 species under 6 genera were actually collected and studied from twelve villages of Puri and Khurda Districts of Orissa.The study proved the dominance of Culicine mosquito species (65.59%). in the coastal districts of Orissa Rao (19S4) remarked that among the Indian Anopheline fauna, Anopheles subpictus Grassi complex is predominant along the coast.The present studies also proved the dominance of Anopheles subpictus, comprising 22.73% of all mosquito population studied and about 65.6% of the over all Anophelines fauna.The second species Anopheles vagus is dominated by 10.03%.To measure the species diversity of the mosquito species of the two districts, Shanon diversity index has been used.The shanon diversity index (H) is the index that is commonly used to characterize species diversity in a community (Stiling, 2002).
Hs= Pi In Pi.

In-Log in
The value of Shanons index has been depicted in the table-3.The value of Shanon diversity index for real communities is often found to fall between 1.5 and 3.5 (Stiling, 2002).From the present investigation it is clear that the mosquito species diversity (H) in the Khurda District was significantly higher than the diversity in the mosquito community of Puri District (Fig. 10).
The TMHD (Per Ten men hour Density) for both the districts, mosquito species has been calculated and is summarized in Table-3.The present findings show highest value for Anopheles subpictus (46.87) followed by the Armigeres (A) subalbatus (36.25) (Fig. ll).
The well recognized malaria vectors Anopheles culcifacies, An. annularis are represented by less than 1 %.The Anopheles culcifacies and An.annularis represent 0.15% and 0.3% respectively in the total sample.The species of Man.indiana and Man.longipalpis have not been reported earlier but are now recorded from the areas of Chilika Lake.
Filarial vector diversity of the coastal districts is very low than that of the diversity of culicine mosquitoes (Hazra and Dash, 1998) but the recent study shows the increase in diversity of filarial vector in the same districts.The low rate of diversity has been shown by Shanons index in Puri District.Seven Anopheles species e.g.An. barbirostris, An. fluviatilis, An. jamesii, An. jeyporiensis, An. karwari, An. philippinensis, An. sundaicus found in the previous studies (Covell and  Singh, 1942) are not found during the present study.
The disappearance of the species An. sundaicus also detected during the Chilika fauna study by Dash et a1. (2000).
The changes in mosquito fauna observed from the Orissa coastal area and Chilika lake may be associated with the major ecological changes, extensive use of insecticides and development in agricultural practices, industrial development, natural calamities like severe cyclones, after effects of tsunami etc.

ACKNO~DGE~
The author is grateful to the Director, Zoological Survey of India, Kolkata and officer-in-charge, EBRC, Gopalpur-on-sea (GM) for providing facilities.I am also thankful to Director, RMRC, ICMR, Bhubaneswar for providing library facilities.
Diagnostic characters: Tarsi with narrow pale rings, most distinct on hind legs; dorsum of abdomen with transverse pale bands.Distribution : In India recorded from West Bengal, Orissa, Assam, North-eastern states and Kerala.Remarks : Breeds in irrigation canal, pond with floating vegetation.Resting in pond bank, vegetation.Recorded from the coastal parts of Orissa.Genus Coquilletidia Dyar Subgenus Coquilletidia Dyar* 1905.Coquilletidia Dyar, Proc.ent.Soc.Wash., 7 : 47.Diagnostic characters: These are yellowish brown mosquitoes of moderate size.The general structure is very much as in Aedes but there are no post spiracular bristles.Distinct from Culex in absence of pulvilli, wingscales narrow and lanceolate, pleurae with only a few small patches of scales.Materials examined: 3 exs.(F), Pratap, Totapada Distt.Khurda, 08.vi.2007,ColI.: S. Dash.Distribution : Found throughout India.Remarks: Rests on the floating vegetation in pond.

Fig. 11 .
Fig. 11.Per Ten Men Hour Density of the mosquitoes collected from the surroundings of Chilika Lake (2006-07).
(Hazra and Dash, 1998)quefasciatus Say and the C. vishnui Theobald group are the common Culicines comprising 17.55% and 10.03% respectively.The species of Armegeres group are also equally prevalent as the Genus Culex.The district wise species composition of Mansonioides shows that it (which species) is dominant in coastal areas like Puri district(Hazra and Dash, 1998).Although M. uniformis, M. annulifera and M. indiana have been found through out the districts but M. longipalpis is exclusively found in coastal belts.Diversity of mosquito fauna of Puri and Khurda Districts of Orissa are shown in Table-l and 2 respectively.

Table - 3
: Per ten men hour density (TMHD) of the mosquitoes collected from the surroundings of Chilika Lake during 2006-07.