Tephritidae: India
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Faunal Diversity in India Tephritidae
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) |
Introduction
Tephritidae, commonly known as fruitflies (although geneticists and some entomologists use the name fruitflies for Drosophilidae) are represented in all Zoogeographical Regions except Antarctica. Their common name is derived from the habit of many species breeding in fruits of different kinds. Barring very few species, almost all the fruitflies, of which biology is known, have phytophagous larval stages. The larvae complete their development while feeding in developing ovaries of fruits and seeds or while mining leaf, stem or root tissues and also forming galls in host plants. Pupation sometimes takes place within the plant, but usually the larvae leave the plant to pupate in soil. Many species of fruitflies are host specific. Members of the family Tephritidae are medium sized flies having the following characters: well developed inferior fronto-orbital bristles in most of the species; post-vertical (post-ocellar) bristles parallel or divergent and never cruciate; wings typically marked in patterns, with the subcostal vein bent sharply upward at nearly a right angle before apex and weakened or evanescent beyond the bend; costa with a break at apex of the sub costa and the cubital cell (anal cell) typically lobate at apex.
Status Of The Taxon
Three different names Tephritidae, Trypetidae and Trypaneidae have been used for the family by various authors; however, the first one is considered valid by recent workers. Tephritidae is placed under the superfamily Tephritoidea alongwith the families Pyrgotidae, Otitidae, Platystomatidae, Richardiidae and Tachiniscidae. Tephritidae is closely related to Platystomatidae and Otitidae.
Global and Indian status
About 4000 species arranged in 500 genera are included in the family Tephritidae of which about 839 species are known from the Oriental Region which include about 320 species from the Indian subcontinent. RADHAKRISHNAN : Tephrilidae: DipIero 305 So far 201 species of fruitflies are known (Kapoor, 1993; Radhakrishnan, 1993) from various parts of India. These are included based on White & Elron-Harris (1992) in 3 subfamilies, 11 tribes and 75 genera. The subfamily Dacinae (tribes : Dacini and Ceratitini) is known by 68 species under 14 genera the subfamily Trypetinae (tribes : Acanthonevrini, Adramini, Euphrantini and Trypetini) by 67 species under 32 genera and the sub-family Tephritinae (tribes: Myopitini, Tephrellini, Terellini and Tephritini) by 66 species under 29 genera.
Geographical Distribution Of The Taxon In India
Most fruitflies have a limited natural distribution probably due to physical, climatic, vegetational and host-specificity factors. However, species that infest a variety of vegetables and fruits (non-host specific) are usually widespread in distribution. About 40 species of Tephritidae are known from West Bengal, 35 form Uttar Pradesh, 30 from Tamil Nadu, 20 from Bihar, 19 from Arunachal Pradesh, 15 from Himachal Pradesh, 13 from Kamataka, 11 from Sikkim, 7 each from Kerala, Punjab, Meghalaya and Maharasthra, 6 each from Jammu and Kashmir, Orissa and Assam, 3 each from Madhya Pradesh and Andaman, 2 from Gujarat and 1 each from Haryana, Rajasthan, Andhra Pradesh, Nagaland and Lakshadweep. Some of the species overlap mdistribution over many of the states. The number of species known so far from each state is far from satisfactory as proper survey and documentation of the family has not been carried out in many of the states.
Biological Diversity And Its Special Features
One of the characteristic features of the fruitflies is the long extendible ovipositor of the females with which eggs are deposited within the plant part in which the larvae grow. Some Tephritids are known to use a pheromone to mark fruit in which they have oviposited which function as a signal to let the other members of the same species know that the fruit is already attacked. The production of such oviposition deterrent or host marking pheromones are suspected to be wide-spread in the family. Generally, there are three larval instars, although some flower associated species complete the first instar prior to emergence from the egg. Faunal Diversity in India About half of all species of fruitflies are associated with flowers including all species of the subfamily Tephritinae. Some of the Cucurbitaceae associated species of Bactrocera and Dacus are either exclusively or occassionally associated with flowers rather than fruit and in some cases specifically the male flowers. Many Tephritinae induce gall formation including root galls, stem galls and galls hidden within flower heads. The larvae of some Trypetinae develop in leaf mines and many ceratitini develop in bamboo shoots. Some species have unusual larval habits developing in deadwood, galls of sawfly and termite galleries. Most fruit infesters drop to the ground and pupariate in soil while most flower breeding Tephritinae pupariate within the host tissue. The number of eggs laid and duration of each life cycle vary from species to species. In fruit associated Tephritidae depending on the species, number of eggs laid can be from 50 to as many as 1500. The life-cycle stage for egg vary from 1 to 20 days, for larvae from 4 to 37 days (some over wintering), for pupae from 6 to 30 days (some over wintering) and for adults from 1 to 11 months. Soon after emergence, the adults of most species require a protein source to permit egg maturation and the plant surface bacteria serve as very important source of nutrients. Most fruit associated Tephritids get attracted to substances which give out ammonia. Many Tephritids exhibit a pattern of lek behaviour in which congregating males defend territories while waiting for receptive females. Mating displays involve the use of wing pattern and movement, sometimes acoustic signals and presentation of nuptial gift of dried secretion from the mouth parts. Temperate species with a narrow host range are usually univoltine while tropical pest species are typically multivoltine. About 35% of the world species attack soft fruits including many economically important commercial fruits. Besides, about 40% of species develop in the flowers of Asteraceae. Most of the remaining species are associated with the flowers of other families or mine in leaf, stem or root tissues during their development. Very few species are non-phytophagous, a typical example being that of TermitorioXJJ termitoxena (Bezzi) reared from the termite galleries in Australia.
Endemicity
About 91.5% of the Indian fruitflies are Oriental in distribution. The Palaearctic eleme{lt is represented by 5.5%, the Ethiopian by 1%, Nearctic RADHAKRISHNAN : Tephritidae: Dip/era and Neotropical by 0.5%. The remaining 1.5% is cosmopolitan in Zoogeographical distribution. Out of the 201 species reported from India, 93 species are endemic which means that about 46.2% of the known Indian species are restricted to the limits of India in distribution. However, out of the 75 genera reported from India, only the genus, Indopllranta is so far known to be endemic to the country.
Threatened And Introduced Species In India
None of the species of Tephritidae are threatened in India. Procecidoc1lares "tiUs, a species of the subfamily Tephritinae belonging to the Neotropical Region was released in the Darjeeling district of West Bengal, Assam, Tamil Nadu and Uttar Pradesh in India in 1963 for the control of the obnoxious weed Eupatorium trapezoidellm. The larvae of the fly form galls on the stems particularly destroying the terminal portion of the weed thereby preventing the weed from growing and spreading further. Though introduction of the fly in Hawaii has resulted in a grand success in eradication of the crofton weed, in India the fly inspite of establishing itself sufficiently well has not been effective in the control of the weed.
Value
The value of the family Tephritidae lies in the habit of its phytophagous larvae that causes some kind of damage or the other while developing in the host plants. Of the approximately more than 130 families of Diptera, Tephritidae cause by far the most extensive damage to plants. Many of the fruitflies (Bactrocera and Ceratitis) are serious pests of economic fruits and vegetables while some of the cecidogenous members (Procecidocltares, Uropltora, Eutreta and Tepltritis) are beneficial in the biocontrol of weeds. The fruitflies have long been considered primarily as pests of many commercial fruits and vegetable crops. Only rather recently have the beneficial members of the family received recognition as agents in the biocontrol of weeds. The cecidogenous members of the family form the majority of such beneficial or potentially beneficial species and most of the tephritids involved are members of the subfamily Tephritinae. About 200 species have been recorded over the world as gall formers, thus ranking the Tephritidae as the second most important cecidogenous family of Diptera after cecidomyiidae. Faunal Diversity in India Based on taxonomic considerations it is estimated that eventually 300-400 species will be found to be cecidogenous. About 20 species of Tephritidae have been used as biocontrol agents of adventive weeds over the world. Out of the 201 species known from India, a few have become a matter of concern as pests of fruits and vegetables. They are Bactrocera (Zeugodacus) cllcurbitae, B. (2.) tau, B. (B.) zonata, B. (B.) dorsalis, B. (Hemigymnodacus) diversa, DaclIs (Didacus) ciliatlls, Olrpomyia vesllviana and AcantilOphillls helianthi. Species under the genera Bactrocera and Dacus are pests of Cucurbitaceous plants (melon, gourd, cucumber, pumpkin, etc.), tomato, chilly, brinjal, pepper, papaya, ber, pear, peach, custard apple, jackfruit, apple, guava, mango and several citrus fruits. Carpomyia vesuviana causes considerable damage to the fruit of ber and Acantlrophillls helianthi to the seed bearing flower head of Safflower, Sunflower and Cornflower crops. Most of the beneficial species belong to the genera Acinia, Ceratitella, Chaelorellia, Euaresta, XantllOchaeta, Procecidoc1zares, Tephritis, Tetreuaresta, Uroplrora and Xanthaciura. Some of the species considered for use in weed control and in the natural regulation of some weeds are of the genera Eurosta, Oxyna, Dioxyna, Ensina, Splzenella, Elltreta, Ellptlrranta, Terellia, Toxotrypana, Trupanea, Zonosemata and Orellia. In India, the fruitfly, Ensina sonchi is found to attack the sow-thistle weed, Sonchus arvensis and the Canada thistle, Cirsillm arvense. Dioxyna sororcula considered a pest of ornamental plants has been found to attack the cobblers peg weed, Bidens biternata. Similarly, Tephritis cardl/alis is reported to breed in the flower heads of the thistle Cardllus edelbergi in Pakistan and possibly Northern India. Tephritis heiseri, Terralia serratulae and Uroplrora stylata are also known to attack the flower heads of various thistles. Extracts of the tephritid galls produced by Paratephrilis transitoria on CacaUa hastala are widely used for tannery in the former U.S.S.R.
Threats
As such no problems or threats can be attributed to the survival of the Taxon. The larvae and pupae of the fruit associated Tephritidae are prone to the attack of a variety of parasitic Hymenoptera particularly of the superfamilies Ichneumeonoidea and Chalcidoidea. The adults of some species of Bactrocera are parasitised by Stylops and tephritid puparia in soil are subject to attack by a variety of predators. Though rates of parasitism in some of the cases are as high as 90%, 0-30% levels of parasitism are more typical. However, birds and rodents eat sufficient attacked fruits to account RADHAKRISHNAN : Tephri/idae : Dip/era for a far higher level of larval mortality. Puparia in soil are highly vulnerable to predators and parasitoids. 38% of mortality has been due to ants. Ground dwelling Coleoptera (Carabidae, Staphylinidae), Neuroptera (Chrysopidae) and Hemiptera (Pentatomidae) are also predators.
Conservation Strategies And Future Studies
Since no major problems or threats are posed on the survival of the taxon, no conservation strategies are suggested. However, future studies are required particularly in view of the economic importance of the taxon being both of harmful and beneficial nature. Much more information that what is available is required on the taxonomy and biology of the pest species occurring in India for formulating proper control measures especially while considering further expansion of National land area for horticulture. KnowleCige of host plants and detailed information on Zoogeography is essential no.t only for the control of pest species but also for quarantine purposes. No serious study has been conducted in assessing the beneficial aspects of many of the Cecidogenous species in India. A proper study in this direction is likely to yield very valuable information on potential species that can be employed in the biocontrol of weeds. It is generally accepted that about 8-12 percent of the world species of most of the Acalyptrate Diptera are represented in lndia. Judging from this, approximately 400 species of Tephritidae can be expected in lndia where as only 201 species are recorded so far which indicates that as yet the information available on the fruitfly fauna occurring in India is far from complete.
Selected References
Bezzi, M. 1913. Indian Trypaneids (Fruitflies) in the collection of the Indian Museum, Calcutta. Mem. Indian MilS., 3 (3) : 53-175, pis. 8-10. Drew, R.AJ. 1989a. Tropical fruitflies (Diptera : Tephritidae : Dacinae) of the Australasian and Oceanian regions. Mem. Queensland MilS., 26 : 1-521. Drew, R.AJ. 1989b. Taxonomy and Zoogeography. In. Frrtitflies (Robinson, A.5. and Hooper, G.H.5., eds.). Elesevier Sci. Pub\., pp. 1-7. Netherlands. Hancock, D.L. 1986a. New genera and species of African Tephritinae (Diptera : Tephritidae) with comments on some currently unplaced or misplaced taxa and on classification. Trans. Zimbabwe scient. Ass., 63 (3) : 16-34. Hancock, D.L. 1986b. Classification of the Trypetinae (Diptera : Tephritidae), with a discussion of the Afrotropical fauna. J. ent. soc. 5th. Afr., 49 (2) : 275•305. Faunal Diversity in India Hancock, D.L. 1990. Notes on the Tephrellini -Aciurini (Diptera : Tephritidae), with a checklist of the Zimbabwe species. Trans. Zimbabwe scient. Ass., 64 (5) :41¬ 48. Hardy, D.E. 1977. Family Tephritidae. A catalogue of Diptera of the Oriental Region. (M.D. Delfinado and D.E. hardy, eds.). 3 : 44-134. Hendel, F. 1927. Trypetidae (Fam.) : In Lindner Die fliegen palaearkt. Reg. 49 : 1-221. Herring, E. M. 1947. Neue Gattungen and Arten der Fruchtfljegen. Sinma seva., 6: 1¬ 16. Kapoor, V. C. 1993. Indian fruitfiies (Insecta: Diptera : Tephritidae). Oxford & IBH publishing Co. Pvt. Ltd., New Delhi. Munro, H. K. 1984. A taxonomic treatise on the Dacidae (Tephritoidea, Diptera) of Africa. Ent. Mem. Dept. Agric. Rep/lb. S. Afr., 61 : 1-313. Radhakrishnan, C. 1993. New record of Dietheria fasciata Hardy (Tephritidae : Diptera : Insecta) from India and its biogeographical affinities. Hexapoda, 5 (1) : 67-70. White, I. M. and Elson-Harris, M.M. 1992. fruitflies of economic significance: tlreir identification and bionomics. CAB international, London.
