Faunal Diversity in India: Apterygota
(Thysanura, Diplura, Protura, Collembola
This is an extract from
FAUNAL DIVERSITY IN INDIA
J. R. B. Alfred
A. K. Das
A. K. Sanyal.
Zoological Survey of India,
( J. R. B. Alfred was
Director, Zoological Survey of India)
The present day insects are grouped into two major sub-classes, namely, Apterygota and Pterygota. The Apterygota are primarily wingless insects which never developed wings during their process of evolution. The sub-class Apterygota comprises four insect orders, namely, Thysanura, Diplura, Protura and Collembola. Majority of these insects play an important role in enriching the soil fertility or in pollination and some of the collembolans are known as the veritable pests of cultivated vegetation. Our knowledge of the Apterygote insect fauna is extremely meagre owing to their difficulties in collection. All the four orders are represented in India.)n fact, they have escaped the attention of field collectors owing to their small size, concealed habits and also some of them being dull or unattractive in colouration. It is also necessary to know the special technique employed in collecting these insects from the field and for extracting them from the soil or leaf litter samples. The present state of our knowledge for each of these insect orders is dealt with separately.
1. Order: Thysanura
The order Thysanura comprise popularly known insects of 'Silver fish' and 'bristle tail' Thysanurans are small, soft bodied, fishlike, scaled, wingless insects. They are considerably larger insects than the other members belonging to the subclass Apterygota. They are easily distinguished by very long many segmented antennae and 2 anal cerci and single median telson projecting posteriorly from the terminal part of abdomen. They are blind as well as eyed and most species are heavily clothed with scales which give these insects a mottled black, brown, silvery or golden appearance. The free living forms are found in the forest floor, under bark of trees, under rocks, in the nests of ants and termites. The members of the family Machilidae occur mostly in the decomposing litter of the forest floor, and are capable of jumping by means of the apical ventral stylets. A few species, such as, Lepisma sacclzarina and Ctenolepisma longicalldata cause damage to books, photographs, bakery and other house hold articles. A fairly large work has been done from the various parts of the world on Thysanura, but in comparison to the world fauna a very little is known on these insects in India. The first record of Thysanura from India is that of Escherich (1903) who described the species Lepisma indica and L. gyrilliformis. Thereafter, Silvestri (1913, 1938, 1948), Janetschek (1964), Wygodzinsky (1941, 1963, 1972, 1994) contributed to our knowledge of Indian species. Since then, works on Indian Thysanuran fauna was neglected for a long time. After that Hazra (1980, 1993) described some Indian Thysanura from West Bengal and Mendes (1990) published on zoogeographic affinities of Indian Thysanura. Extensive and intensive faunistic surveys are required to explore the total Indian fauna of Thysanura.
Status Of The Taxon
Global and Indian Status
The world fauna of Thysanura approximately consists of 5 families, about 130 genera and over 1250 species.
The quite poorly known Indian fauna of Thysanura presently represented by 31 species belonging to 21 g~nera and 5 families and 2 subfamilies. Under suborder Microcoryphia the family Machilidae has 7 genera, 10 spp., and family Meinertellidae has 1 genus and 1 species. The suborder Zygentoma consists of families Lepismatidae with 8 genera and 13 spp., Nicoletiidae with 1 genus and 2 spp. and Ateluridae with 4 genera and 5 spp.
The known range of distribution of the taxa in India are as follows: West Bengal, Sikkim, Orissa, Assam, Uttar Pradesh, Himachal Pradesh, Jammu and Kashmir, Manipur, Meghalaya, Maharashtra, Kerala, Tamil Nadu, Kamataka and Delhi.
Biological Diversity And Its Special Features
The species belonging to the family Lepismatidae correspond to a quite less known assemblage of cryptic, free living, myrmecophilous or termitophilous thysanurans. Several genera are well represented along wide areas, although others are known exclusively by their type species only. Within Microcoryphia the genera like Allopsontlls, Has/undichilis, Hima/ayacllillis and Machi/anus have been reported only from the north eastern mountainous states, Graphitarsus from the southern India and Machi/ontlls from the north eastern India. Allopsontus is endemic to India. Machilanus has wider geographical range of distribution and includes more numerous species. Ctenolepisma has a very wide geographical distribution. Afrolepisma and Xenolepisma show a clear Afro-Indian distribution. The very primitive genus GastrotTteus shows a wide geographical distribution and it has remarkable ecological plasticity, with edaphic, myrmecophilous and termitophilous species. Lepidospora is the only genus, included within Nicoletiidae, from India with approximately 20 species distributed in two sub-genera.
On an analysis of the available literature, it is evident that this group inhabits a wide range of ecological niche. Some members of the family Machilidae occur mostly in the decomposing litter of the forest floor and thus have some role in the process of humification, some are localised and adaptive in different evnironmental conditions like forest floor, under bark of trees, under rocks and in the nest of ants and termites.
Among the known taxa the follOWing 23 species are endemic to India : Allopsontus annandalei, Graphitarsus surindicus, Has/undichilis quadri, HimalayacTtilis muriensis, Maclti/anus insensilis, Machi/anus lapidicola, Machilanus schmidi, Machilis lefroyi, MacTti/oides lawrencei, Macltilontus sp., Afrolepisma nigrina, Ctenolepisma alticola, Ctenolepisma boettgerianllm, Tric1lOlepisma gravelyi, Xenolepisma sllbnigrina, Lepisma indica, Lepidospora notabilis, Assmutltia inermis, Assmuthia spinesissima, Ate/ura typhloponis, Gastrotheus indiCl/s, P/atystylea barbifer, Stylifera wygodzinskyi.
These insects, such as, Lepisma saccharina and Ctenolepisma longicaudata frequently commensals of man are found in houses. They feed upon the starchy matter, under wall paper, book, woolen and silk cloth and thus cause an immense damage of household article and books, for which they are as serious house hold and library pest in India. These insects have also some role in the process of humification.
2. Order: Diplura
Diplura still remains one of the least studied group of Indian fauna. They are soft bodied wingless insects. White or yellow in colour, body devoid of any scales, eyes absent, their length up to 50 mm, without median telson. They are easily distinguished by a paired long filiform or shorter and annular or forcep like cerci. In accordance with their concealed mode of life, all known species are entirely blind. They exhibit semi gregarious distribution. They are generally soil inhabitants and usually found in larger number in the humus soil or in the forest floor, and also under stones or logs in damp environment throughout India. A few are commonly found running about in the nests of ants but whether there is any direct association with the ant is unknown. The knowledge of Indian Diplura is extremely fragmentary, no one in India is actively engaged in studying this group and most part of the country remain unexplored. Whatever information is available about these insects till today is due to the contributions of Silvestri (1913,1937), Conde (1952, 1972), and Mitra and Rao (1977).
Status Of The Taxon
Global and Indian Status
The Diplura is still unexplored in various parts of the world. The world fauna of this group is represented by approximately about 355 species under 77 genera, of which the family Japygidae embodies the largest number of genera and species. Only 16 species under 7 genera are so far known from the Indian subregion. They belong to 3 families, namely, Japygidae, Projapygidae and Campodeidae. No one in India is acively engaged in studying this group and most parts of the country remain unexplored.
The distribution of this order is restricted to eastern and southern parts of India. Information is lacking from other parts of the country due to lack of proper survey in those areas.
Biological Diversity And Its Specieal Features
Diplura has two suborders, namely, Rhabdura and Dicellurata. Under Rhabdura there are two superfamilies, Projapygoidea and Campodeoidea. The former superfamily has two families Anjapygidae and projapygidae and the latter has two families, namely Procampodeidae and Campodeidae. The suborder Dicellurata has only one superfamily Japygoidea under which there are two families, namely, ]apygidae and Parajapygidae.
The members of Japygidae are rather more robust and predatery in habit. Campodeids are also predators and diet of both of these groups of Diplura consists of small soil arthropods. Ghaisas and Ranade (1981) reported about Japyx so/ifugus and mentioned that only 2 to 4 insects are found per square meter. Japyx is more widely distributed than Anajapyx, Campodea and Heterojapyx, where as Projapyx is very rare. Veeresh (1983) mentioned largest population (1200/Sqm) of diplurans in the forest soils of Western Ghats. He also reported small population size during summer which increases in the rainy season and reaches maximum in winter months. Singh and Mukherjee (1971) listed different species of Diplura. Ananthakrishnan (1979) also reported on Diplura.
Among the known taxa about 12 species of this group are apparently endemic to India.
In accordance with their concealed mode of life and rare occurrence they are of no importance economically. Yet as insect member of the soil fauna the diplurans possibly play an appreciable role in preserving the balance therein. These insects are good bioindicator of organic rich soil.
3. Order : Protura
Proturans are one of the rarest, soil inhabiting Apterygotes. Their body is elongate, slender, antennae and eyes absent, their length usually below 2 mm, white or yellowish in dolour. They can be easily distinguished by a median telson which is reduced or absent, their anal cerci absent, the first leg used as a tactile organ; abdomen in adults with 12 segments.
Indian protura represented by three families of which four species under the family Eosentomidae, eight species under family Protentomidae and another eight species under family Acerentomidae have been reported so far. They are generally found in decaying moist organic matter (wooden logs, leaves, etc.), litter and humus layers in forest floors, grassland, foliage of herbs and shrubs and nest of ants under bark of trees. In general, they are found in such habitats where little organic matter and moisture are available. The study of Indian protura started with Schepoteiff (1909); but, there was a long gap after that till to date. Recent work on Indian Protura has been done by Prabhoo (1960-1988). At present no one has worked on the Indian protura and our knowledge about this group is practic~lly nil and whole of the country needs thorough exploration particularly in tropical rain forest areas.
Status Of The Taxon
Global and Indian Status
According to Tuxen (1978) about 260 species belonging to 27 genera under 4 families have been recorded from the world. From India only 20 species belonging to 8 genera and 3 families are known. Among the Indian species 15 species have been recorded from Kerala State alone and rest 5 from other State. Prabhoo (1986) reported that about 99% of Indian area is unexplored as far as the Protura fauna is concerned.
The distribution of this order restricted mostly in the southern part of India. Information is lacking from other parts of the country due to lack of proper survey, although they are supposed to occur in those areas also.
Biological Diversity And Its Special Features
The Proturans are often neglected by soil Zoologists because they are rarely collected and identified. Prabhoo (1986) reported 20 species of Protura belonging to 10 genera from India. These insects have been also recorded from natural habitats in many districts of West Bengal (Choudhuri and Roy, 1970), in certain cultivated and uncultivated fields at Varanasi (Singh and Pillai, 1975), forest and plantation crop (Prabhoo, 1976) and from cultivated and grass plots (Veeresh and Reddy, 1980). Eosentomon is very widely distributed genus and on the other hand, Protentomon, Condeellum and Bolivaridia are restricted in their distribution. Population of Protura is fairly large during monsoon and immediate post monsoon periods while they decline in number during the summer months. Singh and Pillai (1981) reported that Protura prefer humid soil rich in organic matter. Veeresh (1983) reported that Protura are least abundant in summer and maintain highest population in the monsoon. Highest populations of 4800/m2 in the soil of Western Ghats and lowest 3200/m2 from other adjoining tea fields were recorded from Kerala.
Among the known taxa 16 species of this order are endemic to India.
These are the only insects which occur in 20 ems of depth and are devoid of antenna and eyes. Therefore, they are ideal material in the study of insect evolution.
4. Order : Collembola
Collembolans popularly known as 'spring tails' (small and primarily Wingless insects) owing to the presence of spring-like forked jumping organ underneath the fourth abdominal segment. Collembolans are though a specialized offshoot from the main evolutionary line, remote from the main line of insect evolution, gave rise to present day insects (Imms, 1936).
Collembolans are small to minute in size with a range of 0.25 mm to 6 mm in length; antennae primarily with 4 segments; many species without springtails are also common, exhibiting only sluggish movement and with beautiful deep coral red or dark blue colour. No cerci and telson is present at the end of abdomen.
Status Of The Taxon
Global and Indian Status
World over this group of insects are known by a 5,500 species.under 452 genera, 11 families and 2 suborders. Collembolans are represented in India by approximately 210 species under 86 genera, 8 families and 2 suborders.
The collembolans have a very diverse distribution, occurring in all parts of the world, inhabiting a wide range of ecological niche and in any climatic region. They are generally found in the decaying moist organic matter like wooden logs, leaves, etc., litter and humus layers in forest floor, grassland, nest of termite and ant, caves, among moss, fungus, lichens, foliage of herbs and shrubs, snow at high altitude is also known to support certain collemolans. In general they occur everywhere where little organic matter and moisture are available.
The Collemboia have wide range of distribution occurring in all parts of India. These insects are so far reported from Uttar Pradesh, Himachal Pradesh, Kashmir, Sikkim, Nagaland, Meghalaya, West Bengal, Orissa, Kerala, Tamil Nadu and certain parts of Maharashtra.
This group occur in different habitats from North the West Himalayan belt to North Eastern part of India and also in the Gangetic belt, Eastern Ghats and Western Ghat side.
Biological Diversity And Its Special Features
The order Collembola are divided into 2 suborders, each characterised by a distinct body form. The Collembola which have elongated body come under suborder Arthropleona In the Symphypleona, the body is compact and globular. Former represents majority of the collembolan species under families, such as, Isotomidae, Entomobryidae, Poduridae, Hypogasturide, Oncopoduridae, etc. Other suborder comprises of two major families, viz., Neelidae and Sminthuridae.
These insects are often immensely abundant at a specially suitable patch or strech of habitat. An acre of meadow has been estimated to support nearly 2,30,000,000 of these insects from the surface to a depth of nine inches (Imrns, 1959). Mitra et al. (1976, 1979) indicated the rhizospheric effects of various vegetation governing the distribution and diversity of Collembola. He (Mitra, 1993) also pointed out that Collembola can be used as an index of crop production in the Agroecosystem. These insects occur in the vicinity of both south and north poles (upto 80 South latitude in Antarctica); a few species are liVing permanently on glaciers or snow field. They also occur in the coastal areas as well as in the desert. The diversity as well as the greatest number are found in soil with rich organic matter content. Some species live freely on the surface of water (viz., Produra aquatica) and they are less abundant in dry habitat.
The diversity of the Collembola population varied from field to field. Mukherjee and Singh (1970) recorded maximum population of Collembola during March, August and January and minimum during May-June, building up their population during monsoon. Choudhuri and Ray (1967) recorded the highest population in July and August and lowest during February and April. Hazra and Choudhuri (1983) reported an irregular trend of fluctuation usually shOWing maximum in July and minimum in May. Singh and Pillai (1975) recorded 1077/m2 Collembola from banana field where as Prabhoo (1976) estimated 24000/m2 from forest and tea fields. Choudhuri and Roy (1976) reported 12 genera from uncultivated fields of West Bengal. Lepidocyrtus, Cyphoderus and Proisotoma were common to all habitats. Singh and Pillai (1981) reported Onychiurus, Subisotonza, Isotonlllrus, Folsomides as predominant genera found in all habitats. Prabhoo (1986) reported about collembolan community from a bamboo grove and grass plot and recorded 20 species. Prabhoo and Pai (1989) recorded 33 species of Collembola in control site and 13 species in a burnt site. These 13 species found in control site are considered as fire intolerent species. Hazra (1982) and Mitra (1990) recorded Idionzerus sp., Entonzobrya sp., Lepidocyrtus sp., Cyphoderus sp., and Folsomia sp. as most dominant collembola fauna in soil and litter of Silent Vally of Kerala. Hazra and Choudhuri (1983) reported 14 genera. Lepidocyrtu5, Cyphoderus, Isotomina, Xenylla were common both in cultivated and uncultivated sites of West Bengal. Reddy and Das (1983) recorded Isotomidae and Entomobryidae from Pine plantation ecosystem. Sharma et al. (1984) in the Himalayan region recorded that the richness and total abundance of litter microarthopods decreased with the increase in elevation as well the share of collembolans in the total microarthropod population increased with the elevation. Hazra and Choudhuri (1983) found nitrate, organic matter and moisture content of the soil shows significant effects on the distribution of Collembola.
Among the known taxa of Collembola 45 species are endemic to India.
Collembola playa significant role in the breakdown of leaf litter alongwith certain other microarthropods and consequently aiding in the process of humification. Thus they playa key role in enhancing soil fertility. They are also known to enrich the organic content of the soil in the form of faecal matter. Schaller (1950) has shown that a population of 1,00,000 collombola in 1 sq. m. area produces 103 cc of faeces annually. This is equavalent to 0.2 mm deep layer. Collembolans are also being increasingly recognised as bioindicator of soil conditions. These insects are extremely suscaptible to changes in conditions. It is also known that certain collembolan species exhibit sustained tolerance against varied strength of pesticides including most toxic DDT. It has also been reported (Mitra, 1993) that Collembola can be used as an index of crop production in the Agro-ecosystem. Some of them are minor pests in agriculture. For example, Achon/tes annatlls is found destructive to mushroom in India. Sine/la curviseta was reported to infest potato crop at Srinagar, India.
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