Phasmida: India
Contents |
Faunal Diversity in India: Phasmida
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
Walking-sticks, or stick-insects, together with some leaf-insects and a few other related neopteous insects are included in Phasmida. Phasmids arose from Protorthoptera, which persisted only in the Upper Carboniferous Period. The position of Phasmida, oWing to the poor fossil records, occupy the ordinal rank among Orthopteroid insects.
Phasmids are moderate to large sized, and vary from 3.0 cm to 33.0 em in length. The body-fonn usually elongate and cylindrical, depressed and leaf-like; the prothorax is short, the meso and metathorax usually are elongate, and the tergum of the latter is closely associated with that of the first abdominal segment except in Timematodea; the hind pair of legs not modified for jumping; the coxae are small and, except in Timemalodea, wide apart; the tarsi are five segmented, except in Timematodea (3 segmented). The wings often are greatly reduced or absent; the fore-wings (when present) usually are short, leather-like tegmina; the hind-wings (when present) are fan-like and surpassing tegmina. The abdomen has distinct, short, symmetrical, unsegmented cerci (sometimes expanded in female). The male external genitalia are very variable, but asymmetrical. The ovipositor of the female is short and complex. Metamorphosis is gradual and slight. These insects are arboreal or arbusticolous, but a few live on the ground or among grasses and herbs. All phasmids are phytophagous and most of them are nocturnal.
Status Of The Taxon
Global Status
Global phasmids are estimated at about 2,500 species (Kevan, 1982). The majority of species occur in the humid tropics, and a large portions of these are from the Oriental-Australian Region. However, they do occur in drier and in temperate regions. Handlirsch (1930) divided Phasmida into 3 families, i.e., Bacteriidae, Phyllidae and Phasmidae, but Beier (1968) classified it into two families only i.e., Phyllidae and Phasmatidae. This is also followed by Clark (1975), who divided the family Phyllidae into 8 and Phasmatidae into 11 subfamilies. Kevan (1982) called Phasmida as Phasmatoptera and divided it into 2 suborders : Timematodea and Phasmatodea. The suborder Timematodea contains single family, while Phasmatodea contains 10 families. He raised most of the subfamilies of Clark to family rank. The author has followed Kevan (1982) here.
Indian Status
Indian phasmids, as per records, comprise nearly 146 species. This number is very less in comparison to Global phasmid species (Table 1). The main reason for this may be due to less exploration of forest area where these insects are found and non-availability of experts of the group. Though earlier worker like Westwood (1838-40, 1859, 1864), Wood-Mason (1873, 1875, 1876, 1877), Rehn (1904) and Kirby (1896, 1904) have studied Indian Phasmida but major works on Indian Phasmida were done by Redtenbachar (1908), Carl (1913), Karny (1923) and Guenther (1938). After these works nobody has, studied Indian Phasmida. The total number of species and families of Global and Indian phasmids is shown in (Table 1).
Distribution
Family-wise distribution of number of phasmid species in India is shown in Table 2. Table -2 Families No. of species in N.E. Bihar Orissa South North West Anda-India India India India India man with + West Is. unkn- Bengal own locality
Total 8 822 338 2 4 15 Thus it is clear from this table that most of the species are recorded from North-east India, followed by South India. It is worth mentioning here that no phasmid has been recorded earlier from West India.
Biological Diversity And Its Special Features
As mentioned earlier, the body-form of Phasmids is generally elongated and twig-like, occasionally shorter, depressed and leaf-like, or rarely of other form. These insects are unusual for the capability possessed by many (if not all) to regenerate to a considerable degree damaged or lost appendages in the instar following an injury or autotomy. Adults can not regenerate since they do not moult, but they retain the facility for autotomy as an escape mechanism. Phasmids are remarkable for the powers of camouflage that result from extraordinary mimicry of plant stems of many kinds and occassionally of foliage and so forth. These have the habit of entering a state of catalepsis, whereby they become rigid and often feign death. Most of the species can change their colour from instar to instar in order to match their background; some can even change colour without moulting. Various colour¬fonns varing from brown to green and in all except the green variety a change in the intensity of the colour can be produced quite rapidly by migration of pigment granules under the influence of a honnone. High humidity, low temperature and low light intensities cause darkening, while pallor is induced by the opposite conditions, Under normal influences a rhytlunical colour change occurs diurnally (dark at night, light in the day).
The thoracic glands are well developed in the family Bacunculidae. AnisomorpJw and related genera of this family are remarkable that they can squirt out a protective irritant secretions from these thoracic glands for a distance of 30 cm or so. The members of the family phyllidae are recognisable from other members of the order by the striking resemblance, particularly of females, to green (less commonly brownish), broad-leaved foliage. They are strongly dimorphic sexually, and are broadly expanded and dorse-ventrally flattened. The femora and often the tibiae are very short, shorter than head in females, much longer and hairy in males. The tegmina are leaf-like, broad and relatively long in females, covering much of the abdomen, and smaller in males, leaving much longer hind-wings exposed. The hind-wings of females are reduced or even absent. The eggs are laid singly in seed-like oothecea, usually scattered randomly. Many species are parthenogenetic, often continuously so, though occasional males occur in such cases. There are about 5 to 8 nymphal stages.
Phasmids are usually not stridulate, but female leaf-insects have stridulatory teeth an the inner surfaces of the bases of the antennae, and some species of other families strike hind and fore-wings together when alarmed.
Endemicity
The genus Carausius is predominant in South India, specially in Tamil Nadu. The well-known 'laboratory' stick-insects, Carausius morosus, originating in southern India, belongs to the family Lonchodidae. The species of the genera Clilumus and CUl1iculina are generally abundant in N. E. India. The Table 3 shows the position of endemic species family-wise in India.
Value
Relatively a few species are economically important and some may suddenly become abundant and seriously defoliate trees. There is keen interest, specially in the species of Phyllium among amateur naturalist in rearing these insects, and fairly large international exchange occurs. One or two species have become favourite experimental animals to physiologists.
Threats, Conservation And Future Studies
The habitats and ecological niches for insects, specially phasmids, which are shy in nature, are becoming less and less due to considerable deforestation and cutting of trees for meeting human need. Besides, some amateur naturalists and school/college students are collecting these insects for their hobbies or educational purposes. During the faunistic survey by the Zoological Survey of India, parties, it has been observed that phasmids are rarely available. The specimens of some genus like Phyllium are occasionally seen in their natural habitat.
The need to conserve the rare or threatened species of the genera like Phyllium must be popularised. A list of rare or endangered species of phasmids together with their distributional map should be prepared for the common people for their awareness. Collections of these species from their natural habitats should be stopped. There is no active taxomonic expert of the group in India at present. It is, therefore, obvious that expertise on this group is to be developed for explorations, study and inventorisation of this unique insect order.
Selected References
Beier, M. 1968. Phammida (Stab-order Gespenstheuschrecken), In J.G. Melmcke et. al. (eds.), Kllkent/ral's Handbllch der Zoologie, 2d wd., Walter der Gruyter, Berlin, 4 pI. 2 (2/10) ; 1-56. Brunner von Wattenwyl, K. and Redtenbacher, J. 1908. Die Inecklen familie der PII/Ismiden, Leipzig; 1-589, pIs. 1-27. Clark, J. T. 1975. A key to the subfamilies of Phasmida. Ent. Rec. 87: 104-107. Guenther, K. 1938. Neue und wenig bekannte Phasmoiden from the Indian Museum, Calcutta. Rec. Indian MilS., 40: 123-141. Kevan, D. K. McE. 1982. Contribution on "Orthoptera" and "Phasmatoptera" to "Synopsis and classification of living organisms (Ed. S. P. Parker), McGraw Hill, New York et. al. 2 : 379-383.
Kirby, W. F. 1904. A Synomic Catalogue of Orthoptere. London, 1 ; 1-501 Rehn, J. A. G. 1904. Studies in the Orthopterous family Phasmidae Proc. Acad. Nat. Sci. Philad., 56; 38-107.
Phasmida
This is an extract from |
Note: This article is likely to have several spelling mistakes that occurred during scanning. If these errors are reported as messages to the Facebook page, Indpaedia.com your help will be gratefully acknowledged.
Introduction
The order Phasmida includes stick and leaf insects, some of which represent curious examples of mimicry. It is a group of large tropical insects with well developed sclerotised bodies (Gunther, 1953).The stick insects possess elongate and cylindrical body and are often apterous. They resemble twigs in colour and appearance. The leaf insects are flattened and leaf-like, with lamellate expansions of the legs.
Historical Resume
The Phasmid fauna of India was not studied until 1859. Westwood (1859) was the pioneer worker, who had rearranged the Phasmida of the British M~seum and published a monograph, under the title of 'Catalogue of Orthopterous insects' Other works are those of Westwood (1859), Bates, (1865), Woodmason (1875), Brunner vonWattenwyl, (1906-08), Kirby (1910) and Gunther (1938, 1953) who have dealt with the Indian fauna.
Estimation of Taxa
About 2,500 species are known from various parts of the world, out of which 60 species are recorded from India. The Indian species belong to 25 genera under 8 subfamilies. Most of the Indian Phasmida are recorded from North Eas~em Region. However, more surveys are required in mountain regions and forests of the country to better understand the group.
Classification
Gunther (1953) has divided the Order Phasmida into two families, viz., Phylliidae and Phasmatidae; each possesses a number of subfamilies.
Expertise Abroad
Herbert Klante, Zoologist, Linzer Str. 31, D -5000 Koeln 42 Bundesrepublik Deutschland (Germany). D.R. Ragge, British Museum ( Nat. Hist.), Crom\vell Road, London (U.K.).
Selected References
Beier, M. 1968. Phasmida (Sub -Order Gespensthen Schrecken). Handbuch der Zoologie (Helmeke, J. -G, Starck, Dand Wermuth, H. eds), 4 (2) Lief. 6. Bradley, J.e &Galil, B.S. 1977. The taxonomic arrangement of the Phasmatodea with Keys to the subfamilies and tribes, Proc. ent. Soc. Wash., 79 (2) : 176-208. Brunner, V. Wattenwyl, K. and Redtenbacher, J. 1906-08. Die lnsektenfamilie der Phasmiden: 589 pp. Leipzig.
Chopard, L. 1945. OFde des Cheleutopteres, Lechevalier, Paris: 541. Gunther, K. 1953, Uber die taxomomische Gliederung Und die geographiche Verbreitung der Insekten ordnung Phasmatodea, Beitr. Ent. 3 : 54-563. Kirby, W.F. 1904. A synonymic Catalogue ojOrthoptera. Phasmidae, part I, London: 317-423. Ragge, D.R. 1955. The wing venation of the Order Phasmida, Trans. R. ent. Soc. London, 106: 375-392.
