Diptera Chloropidae: India
Faunal Diversity in India: Chloropidae
This is an extract from FAUNAL DIVERSITY IN INDIA Edited by J. R. B. Alfred A. K. Das A. K. Sanyal. ENVIS Centre, Zoological Survey of India, Calcutta. 1998 ( J. R. B. Alfred was Director, Zoological Survey of India) |
Contents |
Introduction
The audit of biodiversity today is far short of reality. It is all the more so of a species rich group like the Dipterans represented in India which in all probability is home for 8-10% of the total number of species on the earth. The alpha taxonomy of hardly 10 of the 98 Dipteran families reported from India and the adjacent countries, is today somewhat adequate. This includes detailed information on hardly one or two of the Acalypterate families, in many of which a shift from predatory behaviour or scavanging to plant feeding has increased the rate of species formation and evolution. Because of their small size and delicate nature many families, especially the Acalypterate Diptera, are often not even represented in most collections. Among the least understood, though fairly large and economically important families is Chloropidae (Acalypterate : Diptera). The Chloropids, commonly called "grass flies" or "green-eyed flies", are small to medium-sized flies (0.5-7mm), rather smooth, predominantly black, but sometimes yellow with black to brown stripes or maculae. They occur almost anywhere in grasslands, moors, marshes, low vegetation in forests, graminous plants and even on window panes. Some frequent flowers and a few, such as, the eye-fly of the Orient (SipllltnCulilla) and eye-gnats (Hippelates) of the New World are attracted to body and eye secretions of man and animals and are important as vectors of certain eye diseases. Their food habits are varied. Many larvae of chloropids are saprophagous and feed especially on the grass from damage by other insects. Others like the destructive frit flies (OscilleIla) and wheat-stem maggots (Meromyza) are phytophagous. A few are gall formers, some devour the egg masses of spiders and mantids and some others are predacious on root aphids.
Status Of The Taxon
The genera and species of Chloropidae were earlier included under the genus Musca in family Muscidae (Sen. lat.), including the first Chloropid species Musca Jrit Fallen (1820) separated several genera and species and treated them under the family Oscinides. Later workers used the family narne Chloropidae. Through the years a little fewer than 300 genera were proposed. Through the contributions of Sabrosky (1941,1964) the number of genera and subgenera were reduced to 200. Chloropidae has traditionally been divided into two subfamilies, Chloropinae and Oscinellinae of which the first has long been accepted under its present name. The second has passed under several narnes and is now recognized under three subfamilies, Siphonellopsinae, Rhodesiellinae and Oscinellinae.
Global Status
Chloropidae has so far been reported from all the faunal realms of the world though they are more abundant in the Afrotropical, Oriental and Palaearctic Regions. About 2150 species under 157 genera have so far been reported from the world. Many of the earlier description are very inadequate. We know practically nothing about the biology and immature stages of more than 98% of the nominal species. Many of the continental and island forest ecosystems still remain unexplored, let alone the canopy fauna but for a few attempts being made in recent years in the Amazonian forests. Hence what is known today may presumably represent hardly 25 to 30% of the world's total.
Indian Status
So far 455 species under 75 genera of Chloropidae have been reported from the Oriental Region. Of these, 155 species under 57 genera have been recorded from India and adjacent countries. These include 44 new species and many new records reported in part'1 of a fauna volume on the group in press. About 60% of these species, including 40% comprising new taxa, were recorded by the author. Another approximately 250 species (including many new) from India and adjacent countries are under various stages of study by the author and are to be published in part 2 of the fauna series.
Distribution
A comprehensive analysis of the distribution of this family in India must await the completion of studies under way on the subfamilies Oscinellinae and Chloropinae. However, based on studies so far completed on the subfamilies Siphonellopsinae and Rhodesiellinae the general pattern of distribution can to a large extent be assessed. Of the 19 genera belonging to the last two subfamilies so far known from the world, 16 genera and 126 species are represented in the Oriental Region of which all the 16 genera and 81 species have been reported from India. As for the species rich subfamilies Oscinellinae and Chloropinae it can be presumed, on the basis of data available including unpublished records, that about 20% of the species so far reported from the world are found in india. But in the ultimate analysis this high percentage may be far removed from reality since concerted efforts through nearly three decades have been made to collect and study the Indian fauna whereas no comparable efforts were put in on a global basis. As for the distribution of the group in India, there is a great concentration of genera and species in the Indian part of the Eastern Himalaya, followed by the Western Ghats, Eastern Ghats and Plains of India in that order.
Biological Diversity And Its Special Features
Chloropidae is a specious family of small flies occupying varied habitats. Some of the species are rather wide-spread and occur in large numbers while many are rather rare. The larvae are mainly phytophagous or saprophagous, sometimes carnivorous and rarely exoparasitic. Some phytophagous species are known pests of cereals like rice, barley and wheat. Some carnivorous species are predators of root aphids and egg masses of poisonous spiders. The adult flies have functional mouth parts and feed also on honey dew. The 'eye flies' and 'eye gnats' annoy man and animals by feeding on wounds or external body openings and are of medicinal importance as vectors of certain eye diseases.
Endemicity
A high level of emdemicity is discemable in the family represented in India. While subfamily Siphonellopsinae is hitherto known by only one species endemic to India, subfamily Rhodesiellinae is represented by a large number of genera and species which are Indian endemics. All the three tribes and 9 of the 11 genera of this subfamily reported from the world are represented in India. This includes 3 genera, Pseudonomba, Bharathella and Amnonella and a new genus (in press) which have their range of distribution restricted to Indian limits. Besides, 55 of the 76 species known of the tribe Rhodesie1Iini from India, 3 of the 4 species of tribe Scoliophthalmini and 3 of the 4 species of tribe Stenoscini known from India are endemic to this country. Thus of a total of 126 species which include many new taxa (in press) belonging to the above 2 subfamilies recorded from the Oriental Region, 62 representing 49.2% of the species and 25% of the 16 genera are Indian endemics. On the basis of data so far available on the remaining 2 subfamilies, it is apparent that a comparably high level of endemicity is noticeable in India in these taxa also.
The extraordinarily high level of endemicity observed in this group in India calls for dilution with the remark that many of the new taxa studied from India in recent years may in all probability be available in the rest of the Oriental Region and the areas beyond, which may become evident on intensive exploration on a regional and global basis. Thus in the ultimate analysis the high percentage of endemicity observed in this family in India may come down to half or even less of what is estimated today. In spite of all these, it is evident that endemicity in this group is remarkably high in India.
Threatened And Introduced Species
Since the majority of species, especially those reported in recent years from India,. have been recorded only once and no attempts could be made in later years to make collections from the type localities of many species, it is not feasible at this stage to evaluate and assign the Indian taxa to the various IUCN categories. At least in a few instances attempts at collecting topotypes in later years have not been usually fruitful. This calls for concerted efforts at intensive explorations to assess the present day status of many of the known taxa.
There is no record of any purposeful and concerted effort for introducing any of the known species of this family into India, since none of the species is known to play any vital role in the biological control of pest species. There might have been accidental introductions of species of genera like Sipll1l11cuIina, which are associated with man, through ships visiting Indian ports or people crossing the Indian borders.
Value
As mentioned earlier, the larvae of some of the phytophagous species cause severe damage to crops like rice, wheat, barley, etc., especially in the far eastern countries and Europe. There is no major report of any damage these flies cause to the cereals in India. Though eyeflies are said to aid in the spread of eye diseases in the Orient, including India, yet the exact role they play and the extent of their impact on the spread of the diseases have not so far been assessed. A few of the species visiting flowers may aid in pollination.
Though some species are known to be predators of root aphids, the role they play in controlling them still needs assessment. Since the biology and information on the immature stages of hardly 1% of the nominal species reported from India is hitherto known, their role in nature have not been evaluated or quantified. But the potential involved in such a large quantum of germplasm represented by a species group of insects can neither be evaluated or estimated on the basis of our limited understanding of the values of biodiversity today.
Threats
The loss of biodiversity of the group the world over, and especially in India, is ecologically and socially excessive. The exact rate of loss is rather unknown. Though the family is widely distributed in India, yet the majority of the species and genera are found in the forest ecosystems. Habitat loss has been and is resulting in a contraction of species distribution and many species are accordingly suffering from genetic erosion i. e. the loss of considerable part of the genetic variation and variability within their populations. Developmental pressure and the resultant habitat loss, as happens today all over India, is causing serious threat to many of the insect groups, including this family of flies. Atleast 50% of the species of the group in India remain unnamed. Many are travelling the road to extinction even before their existence is known. Indiscriminate use of pesticides, deforestation, innundation of forest land by the coming up of hydel and irrigation reservoirs, conversion of forest land into monoculture plantations and other developmental processes are all depleting the distribution and abundance of many of the species of this group.
Conservation Strategies And Future Studies
'Save the whale' has a convincing ring, but 'save the snail'? Attempts to argue the case for the conservation of invertebrates are often met with derision. Yet we ignore them at our peril. For every species of higher form of life disappearing, there are thousands of invertebrates that travel the road to extinction.
The needs of insects do not always coincide with those of vertebrates. Since the requirements of most of the insect species are rather limited and many of them inhabit small ecological niches, it is not safe to assume that protection of large areas for the conservation of vertebrates will automatically safeguard the diversity of lower forms of life also. Because of their diversity and germplasm potential besides the role they play in the maintenance of any viable ecosystem, conservation of this group, as other insect groups, should receive the importance it deserves.
Since the alpha taxonomy of more than 50% of the Indian taxa of this family is yet to be revealed, concerted efforts at intensive exploration of various ecosystems is the need of the hour. Besides, no attempt has been made in India in the past to study the canopy fauna which may represent more than 30% of our species. The biology of 99% of the species so far named remains unattended and this is an area having a busy future. Inter and intraspecies interactions of many of the species of this family and their roles in nature still remain areas of relative darkness.
Selective References
Anderson, H. 1977. Taxonomic and phylogenetic studies on Chloropidae (Diptera) with special reference to old world genera. Ent. 5cand. 511ppl., 8 : 1-200. Becker, T. 1911. Chloropidae. Eine monographische studie. iii. Teil Die Indo-Australische region. Ann. MilS. Nalt. Hlmgarici, 9: 35-170. Cherian, P. T. 1989. Some new genera of Oriental Chloropidae (Diptera). Oriental Ins., 23 : 219-229. Cherian, P. T. 1995. Fauna of India and adjacent countries. Diptera IX. Chloropidae part 1. Siphonellopsinae and Rhodesiellinae. pp. 1-558, 405 figs. (In press). Kanmiya. K. 1983. A systematic study of the Japanese Chloropide (Diptera). Mem. Ent. Soc. WI/sltington, 11: 1-370. Nartshuk, E. P. 1977. Comparative morphological studies on the abdomen and genitalic organs of the grass-flies (Diptera : Chloropide).Tmdy Vsesoy Ent. Obslt., 58 : 87-118. Nartshuk, E. P. 1987. Zlakovie Mukhi (Diptera : Chloropidae) IK Systema, Evolusia i Suvazi s rastennymi. Tmd. Zool. Inst. Acad. Nallk USSR, 136 : 1-280. Sabrosky,C.W.1977. Acatalog ofDipteraoftheOriental Region.FamilyChloropidae. 3 : 277-319. Sabrosky, C. W. 1980. New genera and new combinations in Nearctic Chloropidae (Diptera). Proc. Ent. Soc. Wasltington, 82 (3) : 412-429.
Faunal Diversity in India: Tephritidae (Diptera) C. RADHAKRISHNAN ZoologiclIl Survey ofII/dia, Western Gllats Field Research Station ea/icllt -673002
Diptera Chloropidae
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Introduction
Chloropids are small flies belonging to Section Acalypteratae of the order Diptera. They are smooth, bristless flies, usually predominantly black or basically yellow with black to brown stripes and maculae. They are recognised by the presence of large. plate-like frontal triangle, parallel or convergent postvertical bristIes, sharply margined ridge on propleuron, often peculiar flexure of vein M3 + 4 at the middle of the discal cell and absence of anal cell.
Flies of the family may be observed almost anywhere in grasslands, marshes, moors, and low vegetation in forests, and are frequently collected in great numbers in fields of graminous plants. The larvae are mainly phytophagous or saprophagous, sometimes carnivorous, and rarely exoparasitic. The saprophagous forms feed especially on the grass from damages by other insects. Some of the phytophagous species are known pests of cereals, like rice and barley, and grasses in many regions, and some of the carnivorous species are important as predators of root aphids or eggmasses of poisonous spiders. The adult flies have functional mouthparts and feed on honey dew. Members of this family are frequently captured on flowers. Some, such as the 'eye fly' of the Orient (Siphunculina/unicola) and the 'eyegnats' or Hippelates flies of the New world, annoy man and other animals by feeding at wounds or external body openings and are of medical importance as vectors of certain eye diseases.
Historical Resume
The genera and species of Chloropidae were usually included under the genus Musea in family Muscidae (sens, lat) including the fust chloropid species Musca frit Linnaeus, 1758, in earlier works. In 1803 Chlorops Meigen was erected as the first separate Chloropid genus.'Pallen (1810) included the genera and species in family Micromyzides, but in 1820 he separated several as a new family Oscinides. This family grouping was generally not accepted, as we fmd Newman (1834) and Macquart (1835) placing various genera under different acalypterate families. But most of the earlier workers used the family name Oscinidae, following Pallen (1820), whereas later workers used the name Chloropidae, on the ground that Oscinis was a synonym of Chlorops.
Historical review and revision of the taxonomic work on Chloropidae were made with detailed explanations by Anderson (1963, 1977). The classification of the family in the early part of the present century was principally established by Becker (1910, 1911); Enderlein (1911), and Duda (1930, 1933) for the world; Duda (1934) and deMeijere (1916) for the Oriental Region; and Malloch for the Australian Region. Consequently, a little fewer than 300 genera were proposed. After the significant contributions by Sabrosky (1941, 1964 and 1980), with revisional work on many confused generic classification, the number of genera was reduced to nearly 200. As a result of the works of Nartshuk and Pedoseeva, especially their stress on post-abdominal structures, the objective recognition of the species in the Palaearctic Region has progressed rapidly. Phylogenetic considerations on the family, subfamilies, tribes and generic groups were recently presented by Andersson (1977) and Nartshuk (1977, 1987). Andersson (1977) reviewed 98 old world genera and subgenera from a phylogenetic angle, examined pleisomorphic and apomorphic characters, discussed phylogenetic relationships and proposed new subdivisions of tribes and genera. Nartshuk (1977, 1987) on the basis of 54 genera and 300 species of the family, in the Palaearctic Region elucidated the direction and tendency of evolutionary development of the genital organs.
Chloropidae has been traditionally and conveniently been divided into two subfamilies, Chloropinae and Oscinellinae, of which the frrst has long been accepted under its present name and scope. The second has passed under several names Oscinellinae and Palaeoscinellinae (Duda, 1930), and Oscinellinae, Siphonellopsinae and Heringinnae (Enderleio, 1934). Nartshuk (1987) proposed the superfamily name Chloropidea, separated members of Siphomellopsinae with 8 genera and treated them under family Siphonellopsidae (Duda, 1932) and treated the rest of the genera under four subfamilies Rhodesiellinae, Oscinellinae, Hippelatinae and Chloropinae, under family Chloropidae. She recognized 21 tribes and 141 genera under these groups, besides 2 genera AragarQ and Merochlorops. Of these, all the four subfamilies, 19 tribes and 70 genera are recorded from the Oriental Region, in addition of some genera of Nartshuk's family Siphonellopsidae.
Till 1970, only 23 species under 15 genera were known to occur in India. But within the last two decades all the Indian States except for Himachal Pradesh, Haryana, Bihar and Assam and Union Territory of Lakshadweep and Minicoy islands, have been surveyed, species were collected and studies have been carried out.
Studies from Different Environs
Faunistic surveys, were made in 21 Indian States and all Union territories, except Lakshadweep and Minicoy Islands. Most of the different ecosystems, starting with the Alpine zones of the Himalaya and ending with the shores of Kanyakumari, have been covered during the various surveys by parties and collection of the group has been made from various ecological niches.
Estimation or Taxa
Of the more than 2100 species of Chloropidae, spread under 4 subfamilies, 21 tribes and 141 genera from the whole world, all the subfamilies, 19 tribes and 70 genera are known from the Oriental Region. Of these, all the four subfamilies, 10 tribes, 15 genera and 23 species were known to be represented in India, 6111970. Since then 9 more tribes, 70 genera and more than 270 species have been collected from India. •This includes 5 genera and 82 species new to science. Studies on 45 genera and approximately 150 species are in progress. The studies 'when completed are expected to more than double the number of species known from the Oriental Region so far.
But for some stray references, practically not much work on the taxonomy of Chloropidae of the Oriental Region was done during the period from 1940 to 197Q, and almost nothing on species of the Indian subcontinent. In recent years Kanmya (1983) has been working on some Oriental species available in its eastern belt. Cherian (1976, 1977, 1984, 1989, 1990) •has been studying the family from India and adjacent countries.
Expertise India
In ZSI
P. T. Cherian, Southern Regional Station, Zoological Survey of India, 100, Santhome .High Road, Madras-600 028.
Abroad
C. W. Sabrosky, Emeritus Scientist, Smithsonian Institution, Washington D.C. 20560 (U.S.A.).
K. Kanmiya, Biological Laboratory, Dept. of General Education, School of Medicine, Kurume University, Kurume, Fukuoka 830, (Japan). E. P. Nartshuk, Zoological Institute, Academy of Sciences of the USSR, Leningrad, (USSR). H. Andersson, Swedish Museum of Natural History, C/o Dept of Zoology, Helgonavagen 3, S-22362, Lund (Sweden).
C. H. Paganetta, Museum De Zoologia, Universidade De Sao Panto, Avenida Nazareth, 481, Caixa Postal, 7172, 01000 -Sao Paulo (Brazil).
Selected References
Andersson, H. 1977. Taxonomic and phylogenetic studies on Chloropidae (Diptera) with special referepce to old world genera. Ent.Scand. Suppl., 8: 1-200.
Becker, T. 1911. Chloropidae. Eine monographische studie. iii Tell Die Indo-Australische Region. Ann. Mus. Natt. Hungarici,9 : 35-170.
Cherian, P. T. 1989. Some new genera of Oriental Chloropidae (Diptera). Oriental Ins., 23: 219¬ 229.
Kanmiya, K. 1983. A systematic study of the Japanese Chloropidae (Diptera). Mem. Ent. Soc., Washington, 11 : 1-370.
Nartshuk, E. P. 1977. Comparative morphological studies on the abdomen and genitalic organs of the grass-flies (Diptera: Chloropidae). Trudy Vsesoy Ent. Obsh., 58 : 87-118".
Sabrosky, C. W. 1977. A catalog ofDiptera of the Oriental Region. Family Chloropidae, 3: 277¬ 319.
Sabrosky, C. W. 1980. New genera and new combinations in Nearctic Chloropidae.(Diptera). Proc. Ent. Soc. Washington, 82 (3): 412-429.
