Isoptera: India
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Faunal Diversity in India: Isoptera
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
The order Isoptera popularly known as termites constitute a most fascinating group of social insects because of their polymorphic caste systems (soldier, worker, imagoes), supra-social organisation (division of labour among adults), ubiquity in the tropics, superb nest-building ability (mound, carton-nests, etc.), cryptobiotic mode of life in wood and in soil, and lastly, for their interference to human economy. These insects are easily recognised by their broad head with grinding-bitting type of mandibles (modified in soldiers), moniliform (beaded) antennae, broad thorax with two pairs of almost similar transparent wings (only in imagos), abdomen with transparent and whitish integument (hence known as white-ant), cerci short or long, tarsi with 3-5 segments, external genitalia wanting or rudimentary in both sexes, metamorphosis slight or absent.
Status Of The Taxon
Global and Indian Status
All the known nine families of Isoptera had been in existance since the period of late Mesozoic. But, they unlike their other insect relatives, failed to radiate into diversified climatic and food niches due to their imperfect structural, developmental and behavioural adaptation. As such, this order as a taxonomic group, is neither hyperdiverse containing numerous species, genera, families, etc., than expectation, except in certain groups nor biologi¬cally diverse in all the habitats or geographical areas in the world having numerous species (Table-I). There are four hypodiverse monogeneric families in the world.
These are Mastotermitidae with a single species Mastotermes darwinensis (Frogatt) in Australia, Serritermitidae with only Serritermes serrifer (Bates) in Brazil, Stylotermitidae with a single genus Stylotermes containing eight species from the Indian subregion and Indotermitidae with Indotermes containing seven species in the Orient. Rest of the families are fairly represented by genera and species, of which the most diverse family is the Termitidae with 145 genera under four subfamilies. Taxonomic diversity of Isoptera known from India and the world is shown in Table 1. Table -1 Taxonomic Diversity of Isoptera Taxonomic Categories India World
Distribution
The termite fauna of India is not as vast as the country itself. Out of about 2000 species (induding 60 fossil species) in the world, about 253 species and subspecies under 54 genera belonging to seven families, are so far known from India (Table-I). This vast landmass is characterised by a great variey of phYSiography, climate, soil, vegetation, etc., all of which have influenced termite distribution. Extreme climatic condition is probably the limiting factor. Since termites need a great deal of moisture, they avoid extreme arid as well as cold areas. As such, the species richness gradually decreases towards the temparate higher altitudes of the Himalaya, arid stretches of the Thar desert in the west, but it increases towards the north-eastern borderland.
Termites overcome the adverse environmental conditions by their superb ability of constructing runways and nests. The mound building termites of the genus Odon/otermes are predominently found in hot and humid plains of India. Only a single species O. dis/ans occurs in a temparate altitude of about 2250 m in the Kumaon Hills. Heterotermes inhabits as a house-hold species in the temparate altitudes of the Himalaya to have warmth of house, while two genera, Archotermopsis and Reticulitermes occur in the wild condition in the same area. Psammotermes and AnacantilOtermes are successfully adapted to the arid climate of the Thar desert. The presence of the Neotropical genera, Calcaritemles (only one species in the Great Nicobar) and Rllyllc1lOtermes (only one species in Manipur) in the faunal elemets of India, is of some Zoogeographical interest.
Biological Diversity And Its Special Features
Biological Diversity
Termite diversity refers to the varieties of types or taxa in the order Isoptera or in a given geographical region. Ar€Jion with a number of different taxonomic units (species, genus, etc.) is said to be biologically diverse (biodiversity) and a taxon if contains more species, genera, families, etc., is known as hyperdiverse (taxonomic diverse). A species,with interpopulation differences where each.population get genetically adapted to specific environmental condition is 19Iown to be genetically diverse i.e., genetic diversity of a species or variation of genes within a species. In termites, such studies are not at all done, although many a infra specific categories of population under many species can be discemable. To cite an example, Prorhinotermes flaiJus nygnion and Popoff) primarily a coastal species of the insular landmass df Sr; Lanka, Mangalore, Andaman and Nicobar, is represented by some distinct population in different islands, namely Nicobar, Little Andaman, Nancowry, etc., recognized by their morphological characters and is differing from the typical P. flauus. These population appear in the process of speciation in different islands being isolated by water gaps.
Species diversity which is more concerned to the taxonomists refer to the varieties of species within a region or in a taxon. Angulitermes, for example, is an endemic genus to the Indian subregion, consisting of about 16 species. Of these, 3 to 4 species restrict itself in each of the five physiographic regions in India. Three species, namely, Angulitermes acutus , A. fIetcheri and A. oblusus are closely related and occupy different ecological pockets within the peninsular India. Most of these species show close relationship with A. aculus which itself has a number of distinct population each of which indicates its potentiality to be a distinct species in the .course of future evolution.
However, certain taxa containing more species, genera, or higher taxa than normal expectation, are called hyperdiverse. Examples include• arthropods among animal phyla, insects among arthropods, Coleoptera and Hymenoptera among insects, ants among social insects, rodent among mammals, and so on. The order Isoptera does not fall under this category. Rather termites may be called as hypodiverse, both taxonomically and geographically due to their extrinsic and intrinsic characters, except in some taxonomic units and in some areas. Example include Termitidae among termite families, Termitinae and Nasutitermitinae among subfamilies, Odontotermes, Microcerolermes, Nasulilermes, etc., among the termite genera known from India (Table-I).
Hyperdiversity also occurs in certain habitats or geographical areas in India with respect to termite distribution. The richest concentration of species is found in the tropical rain forests of the Western Ghats in the peninsular and in the north-eastern borderland, as well as in the moist deciduous forest tracts in the foothills of the Himalaya (Table-2). The study of termite species richness in different forest ecosystems in India reveals that termites are found in abundance in the evergreen forest with hot and humid climate as evidenced in the Nilgiri and the Andamans, and less so in the deciduous forest with hot and dry climate as found in the Chhotanagpur (Table-2). But record of quite a number of species in the Thar desert is probably due to thorough collections made by the experts over the years in the area. The maximum number of genera in the Nilgiri show more potentiality for more richer diversity of termites in the area.
But, these findings remain merely tentative, in considering the collections are not made uniformly and without defining exact boundary of these ecosystems. Species and area relationship are not at all considered.
Table-2 Taxonomic Diversity of Termites in different Forest Ecosystems in India Species/Genus
1. Tropical wet Evergreen Forest (Nilgiri Hills) 23/14
2. Tropical moist Deciduous Forest (Nicobar) 22/10
3. Tropical Dry Deciduous Forest (Chhotanagpur) 17/9
4. Subtropical Pine Forest (Kumaon Hills) 20/13
5. Tropical Thorn Forest (Coimbatore) 23/11
6. Desert Vegetation (Thar Desert) 22/11
7. Swamp Forest (Sundarbans) 11/6
8. Insular Andaman Evergreen Forest 23/11
Special features of Termites
There is unique combination of intrinsic and extrinsic factors affecting the biodiversity of termites. These are (i) termites being soft bodied, fragile social insects with polymorphism and cryptic life, devoid of exoskeleton or metamorphosis, are not capable of radiating in all the climatic zones of the world; (ii) the large majority of termites thrive well under tropical climate and only few have invaded cold climatic zones; (iii) termites depend on such food as cellulose, keeping them away from the other food niches; (iv) termites live in closed nest and gallaries with controlled temperature and humidity which restrict their mobility; (v) being social, they virtually restrict themselves in their self made nests except at the time of swarming organized flying individuals and failing to cross even a narrow water gap of 50 km; (vi) they have developed extreme degree of control reproduction that all sterile except one or few reproductive females in the colony; and (vii) termites are most vulnerable to predators than any other animals. All these factors go against to make them taxonomically and biologically diverse.
Endemicity
A total of 170 species of termites is endemic to India which represents roughly two-thirds of the total to 253 species so far known from India (Table-3). Maximum concentration of 73 species occurs in the tropical rainforests in the Western Ghats in the Peninsular physiographic division which is considered as one of the 15 megadiversity provinces of the world.
Other physiographic divisions in India contain almost equal number of species to a total of 20 or so. Maximum number of endemic species belongs to the soil-inhabiting Termitidae (70%), followed by the wood-inhabiting Kaloterrnitidae and Rhinoterrnitidae (30%), of which the latter group is under threat due to human interaction with wood. Table-3 Endemic Species of Isoptera in different Physiographic divisions in India Taxonomic Group HG P NE I C Total Kalotermitidae 5 2 15 5 3 2 32 Termopsidae Hodotermitidae 1 1 Rhinotermitidae 1 1 3 2 4 1 12 Stylotermitidae 3 1 1 1 1 7 Indotermitidae Termltida~ Amitermitinae 5 5 16 1 1 4 32 Termitinae 4 419 1 2 2 32 Macrotermitinae 1 4 4 3 1 5 18 Nasutitermitinae 4 3 14 6 8 1 36 Total 23 207319 19 16 170 H = Himalayan; G = Gangetic; l' = Peninsular; NE = North-east borderland; I = Insular; C = Common to sl:veral divisions.
Introduced Species
About 50 introduced species of termites are so far known (42 indentified, 8 unidentified) in the globe. However, only two species have been introduced in India and one species from Indian subregion had been introduced in the neighbouring countries. Cryptotermes dudleyi Bank, a species originated from the Oriental region, has been introduced in Lower Bengal and Orissa and C. bengalensis Snyder, a native to Africa, is also known to be introduced in the Sundarbans. On the other hand, Coptotermes lleimi (Wasm.) predominently found in India and Pakistan, probably has been established in Java.
Value
The termites held a vital status as a primary consumer and contribute in many ways in the tropical ecosystems. They are involved in increasing soil fertility by disintegrating wood in its many forms and thereby enhance the plant growth. They affect the vegetation by consuming selected components of living and dead vegetation and, as such, incur enormous economic loss. Termites serve as ideal food to numerous animals like, ants, lizards, birds and ant-eaters including man. The mound building termites of the genus Odontotermes support rich fauna as inquilines and guests in their mound playing a co-evolutionary role to increase the biodiversity of the area.
Ecological indicator taxa are not uncommon among termites in India. The occurrence of Nasutitennes in an area, is an indicator of rich biodiversity in rain forest and grass-land. Likewise, presence of RetiCl/litermes indicates temparate climatic condition and Psammotermes general aridity of the area. By liberating methane, they pollute our environment to a considerable extent. The food of termites includes a wide range of plant material, such as, living and dead wood in various stages of decompostition, herbaceous plants and grasses, plant debris, fungi, dung and soil rich in organic matter (humus). As such, a large proportion of energy sources of the ecosystem is potentially shared by termites, causing economic loss. In this respect termites differ markedly from other soil animals, the majority of which are saprophagus, scavengers, feeding on micro-organisms (fungi, etc.), humus and decomposed plant debris. However, man has changed the status of termites from the role of scavenger to pest due to his persuit of extensive extension of agriculture, industries and urbanization.
Threats
The moderate diversity of recent termite fauna of India, is the product of different elements of diversified ecosystems which have maintained considerable degree of stability for long time. Both diversity and stability are now being destroyed at a faster rate by human action. In the process, large number of species are evidently becoming threatened. Particularly threatened are those of wood inhabiting kalotermitids (Neotennes, Glyptotermes) and rhinotermitids (Coptotermes, Reticulitermes) inhabiting fragile and temporary niches, like old dead and dying trees, felled logs and termitid species (Odontotermes and Microtermes) in dung, sand dunes, under stone, garbage and the like. The destruction of the local population of all these species inhabiting such temporary habitats is being caused regularly by rural people for their economic uses. Large majority of the soil inhabiting, mound¬building and humivore species are becoming impoverished from the indiscriminate use of insecticidal chemicals so widely used in agricultural practice in India. The replacement of wooden structure, frame, furniture, etc., in the modem buildings by metal works, is a genuine threat to the house-hold species of the genera Cryptotermes and Heterotermes. Lastly, the wide scale consumption of termite queens of particularly mound building species by the tribals results into peril of these species of agricultural importance.
Conservation Strategies And Future Studies
The moderate diversity of recent termite fauna of India is decreasing in rapid rate due to destruction of its habitats through human activities as has been referred to earlier. Unfortunately, there is no real estimation of species which are under threat or becoming rare. Obviously, they need conservation for our own survival, since some of them are architect of our landscape and others are harmful. As such, conservation of these insects is a very critical and sensitive problem.
However, our conservation strategies are directed to establish numerous fairly large 'Nature Reserves' to ensure in-situ conservation of the diversity and stability of our living resources in general. In reality, these are not adequate for vast magnitude of our insect fauna due to ill management, exploitation, insufficient in number, size, and unsuitable location.
Realizing all these difficulties conservation criteria of species on priority basis can be considered based on the importance of taxonomy, ecology, biology, co-evolution, etc. Primary creteria for conservation of a species should be relatively rare and unique in taxonomic classification in comparison to others. To cite an example. Archoptermopsis wroughtoni (Bugnion and Popoff) a sole living representative of Termopsidae occurring in the western Himalaya, is under threat due to ecodisaster in the area. Likewise, ecological role played by some of the mound-building species of Odontotermes and co-evolutionary role played by termitophilous beetles in the nests and flagellates in the gut of Coptotermes, are unique criteria for conservation. In fact, the species under threat as mentioned in the preceeding section need protection on their own status and merit.
However, there are two opinions, the species destined to extinction within matter of decades need to be saved. Other aim is to give prior attention to species under threat by the time before they are lost. Some may suggest that the most advanced genera, Naslltitermes and Hospitalitermes which are so plastic in adaptive changes in human dominated India, need no protection in comparison to other primitive and relict genera. The detailed study of the status and preparation inventory of the species occurring in abundance in the eastern borderland, the peninsular and the foothills of the Himalaya, is a profitable area of future investigation to get more insight into their strategy of effective conservation.
Selected References
Bose, G. 1984. Termite fauna of Southern India.-oee. Pap, Ree. zool. Suro. India, No. 49; ix+I-270+1 pp. Chhotani, O. B. 1997. Fauna of India ([sop/era), 2 : xx+1-800. Eggleton, P. et al. 1994. Explaining Global termite diversity : Productivity and history.-Biodiver. & Cosero., 3 : 318-330.
Maiti, P. K. 1983. Termite fauna (Isoptera) of West Bengal, India. Their recognition, biology and ecology. Oee. Pap., Ree. zool. Suro. Indltl, No. 42 : iv+152, 4 figd. maps. Maiti, P. K. 1994. Termite fauna of the islands of Andaman and Nicobar, Indian Ocean.-Oce. Pap., Rec. zool. Sum India, 1-55. Maiti, P. K., Lahiri, A. R. ., Saha, N. and Roy, P. H. Insecta: Termites.-Fauna of Meghalaya, State Fauna Series 6, part 3. (in Press). Krishna, K. and Weesner, F. M. 1969 Biology of Termites. Vol. I : xii+598 pp. New York and London (Academic Press). Roonwal, M. L. and Chhotani, O. B. 1989. Fauna of India ([sop/era), 1 : vii+I-672.
Isoptera
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Introduction
Termites or white ants belong to a small onJer of insects, Isoptera. They are one of the most fascinating group of insects due to their primitiveness in orgin in the Cretaceous period, ubiquitous in distribution in the tropics, polymorphic ~aste system, cryptobiotic mode of life helping them pass unnoticed, superb architectural. ability in making nests, unique ecological adjustment, and for their immense economic importance. In search of food and shelter, termites cause considerable damage to wood in forest and agricultmal crops, to timbers in storage and in buildings, to books, clothes and other articles of cellulosic orgin. It is estimated that the amount of loss thus caused by termites in India alone runs to several millions of rupees per year and the loss allover the world must be something colossal.
India being a tropical country with varied physiography. climate and vegetaion, has more than 200 species of tennites, distributed from the plains to the high altitude of the Himalaya. Tennite distribution is generally limited by certain combination of factors, such as, tropical climate, restricted diet of cellulose, consequence of soft body forcing them to live in closed nests, vulnerability to predators and weak flight. The phylogeny of the termite genera is better known than many other groups of animals of comparable size. This is due to constellation of multiple characters available from imago, soldier and worker castes, availability of more than 60 fossil species, receprocal phylogeny of termitophiles, symbiotic flagellates, etc. Moreover, phylogeny in many instances is correlated with ecological, geographical and palaeontological parameters.
The study of termites has been used to illustrate various evolutionary principles, such as, homology, covergence, parallelism, divergence, progressive and regressive, and adaptive evolutionary concepts.
Large number of invertebrate (beetles, flieSl and others) including some fungi, have well adopted to living either in te~ite gut (flagellates) or in their nest from the very bigining of their evolution, leading to interesting relationships. Such intimate relationship with termitophiles and symbiotes has thrown light to understand the reciprocal evolution of both the host termites and their associates.
The cryPtobiotic mode of life in termites has made them unique subject of study. The main atttaction is due to their role in disintegration of wood and cellulose, their place in the food chain of many tropical animals, their close association with fungi, termitophiles and parasites, their unique symbiotic relationship with protozoans and .bacteria; their complex behaviour and nest constuction, their mechanism of caste differentiation, intricate social life, etc.
The 'recognition of the species it) termites is very difficult due to minor variations in morphological characters in all the castes, namely, imagos, soldiers and workers. However, the soldiers, primarily adapted for defence of the colony, exhibit comparatively significant characters for taxonomic identity. As such the museum collections represented by soldiers, are essential for taxonomic purpose. Imagoes and workers associated with the soldiers are identified indirecdy in most of of the cases. However, the generic identification is easy as compared to that of species.
Historical Resume
i) Pre-1900
India has the oldest citation of reference on termites in literature by the name as ghuna (wood destroyer) particularly in the ancient sanskrit text, the Rig Veda (ca. 1350 B.C.); and as kasthaharilca in the Ramayana and other sanskrit literature. The oldest scientific name of a termite species, Termes fatale "from Indiae" appeared in "Systema Naturae" 10th edition, which is considered as the starting point of animal taxonomy published by Linnaeus (1758). Linnaeus recognized three species of termites, and put them under .two different orders, namely, Neuroptera and Aptera. However, the species, Termesfatale is actually from Surinam, South America, and not from India.
Work from• India was initiated in 1779 by Konig on a mound building termite ~south India. This was later on identified as Odontotermes redemanni (Wasmann) by Roonwal (1970) althougb others referred to it as Termes fatalis K6nig (H~gen, 1858; Green, 1913). The other three species dealt with by K6nig (1779) are now in Anacanthotermes Jacobson, Macrotermes Holmgren and Hospitalitermes Holmgren. After KOnig's publication, only 16 species were brought to light upto the end of 19th Century by Rambur (1842); Walker (1853); Hagen (1858, 1859); Brauer (198~); Was mann (1893, 1896) and others.
Classification : Since the time of Linnaeus, the termites were assigned to different Orders, Suborders and Tribes, until Brulle (1832) put them in the order 'Isopteres' The placement of termites in this order was not accepted by the then workers (Latereille, 1802; Walker, 1852 and Hagen 1858). However, after a lapse of many years, Comstock and Comstock (1895) revived the status of the order Isoptera. Credit goes to Hagen (1858) who recognised for the fust time four genera under the Order, namely, Kalotermes Hagen, Termopsis Desneux, Hodotermes Hagen and Termes Linnaeus, and to Froggatta (1896) for recognising four sub-families namely Calotermitinae, Rhinotermitinae, Glyptotermitinae and Termitinae under a single family Termitidae. Thus, the foundation of termite classification was laid during this period.
Catalogues, lists, etc. : The list of Neuropterous insects (including termites) were published by Walker (1853) and Hagen (1858). The latter author also published a synopsis of Neuroptera of Sri Lanka in successive years (1858 and 1859).
ii) 1901-1947
The resident zoologists in India, mainly attached to Imperial Agricultural Research Institute, Pusa; Forest Research Institute, Debra Dun; and Zoological Survey of India, Calcutta, realised the importance of studying these noxius insects and got them identified from foreign experts. Termites from some parts of India and Sri Lanka were worked out by Wasmann (1902) and Desneux (1904, 1906, 1908); those from Sri Lanka by Holmgren (1911), from south India by Holmgren (1912, 1913), from different areas of India by Holmgren and Holmgren (1917),' from Abor Hills by Silvestri (1914), from Barkuda Island by Silvestri (1923), from Sri Lanka by Bugnion•(1912, 1913, 1914), Bugnion and Ferrier (1911), Bugnion and Popoff (1910), John (1925), and Kemner (1926, 1932); from India by Snyder (1933, 1934), from India and Burma by Gardner (1944) and others. As a result, an addition of about 130 species was made during this period.
References to termites were made by different •workers in their books etc. Lefroy (1909) in 'Indian Insect Life' listed 20 species grouped in three genera. Fletcher (1914) listed only three species and Ayyar (1940) in his book on South Indian insects made some casual mention of termites. However, valuable biological informatipn on 50 species is available in the book 'The Ecology and Control ofForest Insects ofIndia and the neighbouring countries' by Beeson (1941).
Classification : At the begining of 20th century, Desneux (1904) compiled the available knowledge in the 'Genera Insectorum' under Isoptera, with inclusion of a single family Tennitidae containing three subfamilies, Calotermitinae, Mastotermitinae and Termitinae. However, Mastotermitinae gained the status of a family later on (Silvestri, 1909). Synder (1949) published a more sound classificatory catalogue, following the contributions of various workers including those from the Indian region (Holmgren, 1910, 1911; Green, 1913; Snyder, 1920, 1933; Light, 1921; Margabandhu, 1934, etc.).
Phylogeny : The phylogenetic aspects of termites were first discussed by Holmgren (1911, 1912) including some genera from the Indian region, who put emphasis on the characteris~c of imago-wodcer mandibles. This has been proved an ideal conservative character on which the present day phylogenetic study is based, supported by some other characters. On the other hand, Hare (1937) based his phylogenetic study on the basis of the development of soldier's mandible, which today seems to be less sound.
Catalogues, lists, etc.: The references of some 30 species of termites from the Indian subregion, could be found in a catalogue compiled by Desneux (1904),44 species from Sri Lanka by Green (1913) and of 119 species from India and Sri Lanka by Margabandhu (1934, 1935).
iii) 1948 -1990
This is the most productive period as far as the termite research is concerned in the entire world including the Indian region. The basic impetus came from two outstanding publications, namely World Catalogue by Snyder (1949) and Phylogeny of World Termite Genera by Ahmad (1950).
The taxonomic work in India gained its maximum momentum during this period under the initiative of Roonwal frrst at the FRI, Debra Dun and later at ZSI, Calcutta and ZSI, Jodhpur. He along with his collaborators namely Sen-Sarma, Kumar Krishna, Chhotani, Chatterjee, Thakur, Thapa, Bose, Maiti, Venna, Rathore, etc, worked on different aspects. The termite research at ZSI, Calcutta flourished from 1956 under Roonwal and his students, Chhotani, Bose and Maiti, with reference to taxonomy, morphology, phylogeny, zoogeography, biology and ecology. Numerous publications were mad~, including a 'Fauna of India' volume on the lower termites by Roonwal and Chhotani (1989). Another volume in this series is awaiting publication.
Revisionary Works : At the begining, emphasis was laid to revise common genera containing disputed species, for example Neotermes Holmg. and Glyptotermes Frogg. were revised by Roonwal and Sen-Sarma (1960), Coptotermes Wasmann by Roonwal and Chhotani (1962), Cryptotermes Banks by Chhotani (1970), Glyptotermes by Chhotani (1975), Stylotermes Hol~g. and Holmg. by Mathur and Chhotani (1959), Mierocerotermes Silvestri by Prashad, Sen-Sarma and Thapa (1967), Microtermes Wasmann by Chatterjee and Thakur (1964), Hypotermes Holmg. by Chatterjee .and Thakur (1963); Eurytermes Wasmann by Roonwal and Chhotani (1966), Nasutit~rmes Dudley by Prashad and Sen-Sarma (1966), Odontotermes Holmg. by Thakur (1981) and Heterotermes Frogg. by Thakur and Sen-Sanna (1979).
State Fauna: Considering the vastness of the Indian subcontinent, State-wise study of termite fauna gained importance. The fauna of Assam region (N.E. India) was published by Roonwal and Chhotani (1962), Rajasthan by Roonwal and Bose (1964), Tripura by Sen-Sarma and Thakur (1979), West Bengal by Maiti (1983), Orissa by Chhotani and Das (1983), and South India by Bose (1984). The fauna of some neighbouring countries were also studied, for instance, the fauna of Paksitan by Ahmad (1955), Indonesia by Roonwal and Maiti (1966), Bangladesh by Akhtar (1975), Bhutan by Roonwal and Chhotani (1977), and Sabah, West Malaysia by Thapa (1982).
Many important discoveries were made during this period. The most significant is the discovery of a family Indotermitidae (Roonwal and Sen-Sarma, 1960), with type genus Indotermes. The validity of this family however, has been questioned (Krishna, 1979). A number of genera, namely, Posteleetrotermes Krishna, Epicalotermes Silvestri, Calearitermes Snyder, Psammotermes Desn., Speeulilermes Wasmann, Anoplotermes Muller, etc., were recorded for the first time from Indian region indicating zoogeographical significance. A total of 157 species were added to the known fauna, to make a total of about 300 species altogether known from the region.
Classification : The foundation of present day Isoptera classification was laid by Synder (1949) and Grasse •(1949) in two separate contributions, which have been generally accepted with some minor modifications. Both the classifications recognized six families, but Mastotermitidae was divided into two families in one (Synder, 1949) and Hodotermitidae into two families in another (Grasse, 1949). This system was further substantiated by phylogenetic study based mainly on the character of imago-worker mandibles.
Out of nine families recognised so far, except two families, Mastotermitidae (confined to Australia) and Serritermitidae (Brazil), all other families, namely Kalotermitidae, Termopsidae, Hodotermitidae, Rhinotermitidae, Stylotermitidae, lndotermitidae and Termitidae occur in the Indian region. The largest family, Termitidae, often referred to as higher termites, contains three¬fourth of the known species. The subfamilies, Termopsinae and Stylotermitinae were raised to family level by Grasse (1949) and by Chatterjee and Thakur (1964) respectively.
Phylogenetic Studies: The first phylogenetic account was proposed by Ahmad (1950) mainly based on the characteristic feature of the imago-worker mandibles. This pattern remained almost unchanged except some additional works done subsequently, e.g. by the study of entiric valve of digestive tract and wing-micro-sculpturing (Roonwal and co-workers 1974-1988).The phylogeny of Kalotermitidae was revised by Krishna (1961), Nasutitermitidae by Sands (1957), Capritermes complex by Krishna (1968), Stylotermitidae and Indotermitidae by Roonwal (1975), Nasutitermitinae by Sen-Sarm~ (1968), Anoplotermes -Speculitermes -complex by Roonwal and Chhotani (1966), and Grallatotermes -complex by ~en-~arma (1966).
Catalogues. lists. bibliographies. reviews etc. : The frrst ever world Catalogue was published by Snyder (1949), which stimulated research around the world. Catalogue of the Indian Isoptera was published by Rattan Lal and Menon (1953), and that of Isoptera collection present in F.R.I., by Roonwal and Pant (1953), which was revised by Mathur and Thapa (1962). Roonwal (1962) gave an excellent review of the systematic work done on world termites (1949-'60), appended with a catalogue and a bibliography. More recently, Chhotani (1972,1977) reviewed the taxonomic work done on termites of the Indian region appended with a catalogue and a bibliography.
Zoogeography: The first analysis of origin, dispersal and zoogeography of the world termites was made by Emerson (1955). Zoogeography of the regional fauna has been discussed by many authors, e.g. of Assam region by Roonwal and Chhotani (1965), Bhutan by Roonwal and Chhotani (1977), Rajasthan by Roonwal and Bose (1964), Andaman and Nicobar Islands by Roonwal and Bose (1965,1970), West Bengal by Maiti (1983), Bangladesh and Pakistan by Akhtar (1974,1975). Zoogeography of some genera, namely, Cryptotermes (Chhotani, 1970), Glyptotermes (Chhotani, 1975) and Odontotermes (Thakur, 1976), were also analysed. The origin, dispersal and evolution of termites in the islands of Andaman and Nicobar have been discussed by Maiti (1977,1979).
Biology: The progress on biological research of Indian species, however, does not commensurate with that of taxonomic research. Some biological notes were incorporated in the faunistic reports. Specific studies on different termites are limited to the nature of infestation in wood and wood products, nest structure, gallery pattern, swarming period, colony development,fungus comb, nest population, etc. The data on these aspects are available in the contributions of Beeson (1941), Mukherjee and Mitra (1949), Roonwal (1970,1979), Sen-Sarma et ale (1975) and Maiti (1983).
The nest structure of Coptotermes (Roonwal, 1954,1959; Roonwal and Chhotani, 1962,1967), Microcerotermes (Roonwal, 1979), Odontotermes (Roonwal, 1973) and arborial carton nests of Nasutitermes (Chhotani and Bose 1979) have been described in detail. The general biology of local termite fauna of Dehra Dun (Mathur and Sen-Sarma, 1959, 1960,1962; Chatterjee and Sen-Sarma 1962; Sen-Sarma, 1962), West Bengal (Maiti, 1983), Rajasthan (Roonwal and Verma, 1973; Roonwal and Rathore, 1974, 1975, 1976, 1978; Roonwal 1975) and penisular India (Roonwal, 1978) are studied.
Ecology: The ecological investigations on Indian termites gained less attention than it deserves. Only a few species have be.cn studied with reference to temparature and humidity responses (Sen¬Sarma, 1969, 1974, Sen-Sarma and Gupta.1968; Sen-Sarma and Misra, 1969, 1971, 1976), termite and fungus interactions (Bakshi, 1962, Mukherjee and Mitra, 1949), termite and symbiotic flagellate association (De Mello 1919,1928,1937,1941; Chakraborty and Banerjee, 1956; Das, 1972, 1974, 1983; Uttangi, 1959, 1962; Mukherjee and Maiti, 1988,1989) and swarming period (Mathur, 1962; Maiti, 1983).
Studies from Different Environs
During the post Independence period, some preliminary work on the composition and faunal strength of termite fauna of different environs has been available. The arid zone fauna of Rajasthan was studied by Roonwal and Bose (1964); that of humid zone of North -east India by Roonwal and Chhotani (1962); of temperate and montane areas of the north-west Himalaya by Chatterjee and Thakur (1967); the deltaic and the sub-Himalayan West Bengal by Maiti (1983); of Bhutan Himalaya by Roonwal and Chhotani (1977); of the peninsular tract by Bose (1984); and the insular areas of the Andaman and Nicobar by Roonwal and Bose (1965, 1970) and Maiti (1977, 1979). Studies on termites of Meghalaya and Tripura are in progress at ZSI, Calcutta.
Estimation of Taxa
Out of nine families recognised so far, seven families are represented so far in the Indian region. The scrutiny of literature shows that about 300 species under 45 genera occur as shown below :
Classified Treatment
Family Tennopsidae
Members of this family inhabit primarily wood. They are divided into three genera allover the world. In India, the family is represented by species, Archotermopsis wroughtoni (Desneux), described in 1904 from the Himalaya. This species has undergone several nomenclatural changes and its biology is worked out better than any other species.
Family Hodotennitidae
Out of five living genera known so far from the world with a total of 12 species only, one genus Anacanthotermes occurs in this region, represented by four species, of which A. baluchistanicus Akhtar is described recently from Pakistan (Akhtar, 1972). The taxonomy and distribution of all the species have been dealt recently by Roonwal and Chhotani (1989).
Family Kalotermitidae
The members of this family strictly inhabit wood in its many forms, including dead portion of live trees. Out of 24 genera known so far, nine genera represented by 56 species occur in this region, which have been extensively studied by Indian workers (Roonwal and Chhotani, 1989). Of these genera, Postelectrotermes Krishna, Calcaritermes Snyder and Epicalotermes Silvestri are recent addition to the Indian fauna (Roonwal and Maiti, 1966; Roonwal and Chhotani, 1983; Chaudhury and Ahmad, 1972). Altogether 33 species are described recently.
Family Rhinotermitidae
The members of this family feed on dead and decaying wood and live in cracks and crevices of the trees, with or without soil connection~ Some species are capable of transporation through floating logs like that of coconuts, and thus got introduced in the coastal areas of different continents. Eight genera represented by 28 species occur in this region. Out of a total of 13 genera known from the world, 12 species have been described as new to science by recent workers, vide Roonwal and Chhotani (1987).
Family S tylotermitidae
This small family contains a single living genus Stylotermes distributed in the Oriental region. It has three segmented tarsi as also in Indotermitidae and also. share some characters of Kalotermitidae and Rhinotermitidae. All the members inhabit the dead and decaying portions of standing trees. Since its establishment by Holmgren and Holmgren, 1913, the family was represented by only species Stylotermes Jletcheri Holmgren and Holmgren, until seven more species have been added by the recent workers.
Family Indotermitidae
This small family is represented by single genus Indotermes Roonwal and Sen-Sarma, (1958). Sinotermes erected by He and Xia (1981) from China has recently been merged under it (Roonwal and Chhotani, 1989). As Such, genus Indotermes contains seven species from South and South¬East Asia. All its members are subterranean in habit.
Current Studies
Active research on termites is being conducted in ZSI, and its Desert Regional Station, Jodhpur, and in FRI, Debra Dun. Recently biological investigations are also being taJcen up in the Department of Zoologyt Vishwa Bharati, Santiriiketan. Some research activities are also in progress in certain Universities in South India.
Expertise India
In ZSI
P. K. Maiti, A. R. Lahiri, N. Saha & P. H. Roy, all of ZSI, M-Block, New Alipur, Calcutta 700053. O. B. Chhotani &O. Chhotani (nee Bose), ZSI, Nizam Palace, 13th floor, 234/4, AJ.C. Bose Road, Calcutta 700 020. N. S. Rathore, ZSI, Desert Regional Station, Paota B Road, Jodhpur (Rajasthan).
Elsewhere
M. L. Thakur &R. S. Thapa, Forest Research Institute, Dehradun (U.P.). P. K. Sen Sarma, Birsa Agricultural University, Kunke, Ranchi (Bihar).
Abroad
W. A. Sand &R. M. C. Williams, British Museum (Nat. Hist.), London. IItJl*m 307 Ie. Krishna, Howard University. Barbar L. Thome American Museum of Natural History, New York. W. G. H. Coaton, J. E. Ruelle and J. L. Sheasby, Plant Protection Research Institute, Pretoria (S. Africa). M. Ahmad and M. S. Akhtar, Punjab University, Lahore (pakistan).
Selected References
Akhtar, M. S. 1975. Taxonomy and Zoogeography of the termites (Isoptera) of Bangladesh. Bull. Dept. Zoo. Univ. Panjab, Art. 7 : 1-199.
Bose, G. 1984. Termite fauna of Southern India. Occ. Pap. Rec. zool. Surv. India, No. 44 : ix + 270 pp.
Chhotani, O. B. 1980. Termite pest of agriculture in the Indian Region and their control. Tech. Monogr. 2001. Surv. India, No.4: 94 pp.
Maiti, P. K. 1983. Termite fauna (Isoptera) of West Bengal, India. Their recognition, biology and ecology. Dcc. pap. Rec. 2001. Surv. India, No. 42 : 152 pp.
Roonwal, M. L. 1970. Termites of the Oriental Region. In : Biology o/Termites (Ed. K. Krishna and F. M. Weesner), Vol. 2: 315-391.
Roonwal, M. L. & Chhotani, O. B. 1962. Termite fauna of Assam Region,.Eastem India. Proc. Natn.lnst. Sci. India, (B) 28 (4) : 281-406.
Roonwal, M. L. &Chhotani, o. B. 1989. The Fauna ofIndia and the adjacent countries, Isoptera (Termites), Vol. 1 : viii + 672 pp., 315 figs. Zoological Survey of India, Calcutta.
Roonwal, M. L. &Sen Sarma, P. K. 1960. Contributions to the systematics of Oriental Termites ICAR Ent. Monogr. No.1: xiv + 407 pp. Snyder, T. E. 1949. Catalogue of the Termites (Isoptera) of the World. Smiths. Misc. Coli., 112 : 490 pp.
Sen-Sarma, P. K., 'a a1. 1975. Wood destroying termites 0/ India (Final Tech. Rep. PL 480 Project A 7 -FS-S8) ; 198 pp.
