Download Chapter I INTRODUCTION AND OBJECTIVES

Chapter I
INTRODUCTION AND OBJECTIVES
1.1
INTRODUCTION
The Arthropoda, which includes insects, spiders, mites, and their relatives, is
without question the most successful group of organisms on the planet. Insects alone
account for nearly 55% of all species known to science (Barrowclough, 1992;
Schauff, 2004). Insects comprise the largest group of organisms and are involved in
various vital „ecosystem services‟ such as pollination, decomposition, herbivory and
biological control as well as contributing directly to human-based economies through
silk, lac and honey production (silkworm, lac insects and honey bee). India is one
among the twelve mega bio-diversity countries of the world and we also realize that
80% of the insects are endemic in India (Murugan, 2006).
In the class Insecta, the Lepidoptera fall within the division of endopterygota
(=Holometabola). The adult bears two pairs of membranous wings, usually clothed
on both surfaces with overlapping scales. The mouthparts of the adult are frequently
modified into a long coiled proboscis, which occurs in no other order. Lepidoptera
pass through a complex metamorphosis of egg, larva and pupa to adult.
The
Lepidoptera, in common with all other insects, have the soft parts of the body held
inside a hard exoskeleton composed of a substance known as chitin. This chitinous
exoskeleton, together with the spiracular system of respiration, imposes certain limits
on the development of the group. The respiratory system, depending as it does on the
flow of air through the spiracles and trachea throughout the body, has limited the
size to which insect can develop (Barlow, 1982).
The total number of known species of Lepidoptera makes up about 10% of
total animal kingdom and is roughly equivalent to the number of flowering plants
species known (Srivastava, 2002). Lepidoptera is the second largest order of class
insecta and most fascinating group. The present total number of Lepidopteran
species approaches near 2,00,000 most of which are moths (Heterocera) and only
about 15,000 are butterflies (Rhopolcera) (Hampson, 1891). Order Lepidoptera
comprises Butterflies, Moths and Skippers, which are well known to every observer
in nature, of which the butterflies have been thoroughly studied by many researchers
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and still more research is coming through. In spite of the fact that moths outnumber
butterflies, not much has been worked on them. Whatever information is available is
only on those, which affect crops, or those, which yield silk. On controversy among
all insects moths are mostly known for there diversity of shapes, size and colour
patterns. The word Lepidoptera means scaly winged. The most characteristic feature
is layer of short, flattened hairs or scales that covers both surface of wings and
partially on all other parts of body. Moths can be differentiated from Butterflies due
to there nocturnal activity, presence of pectinate, bipectinate, lamellate and filiform
antennae and possession of unique spine like structure supporting their hind wings.
Moth included over 55 different families (Hampson, 1891).
A larva of moth feeds upon the leaves, soft stem of plants. Although many
Lepidoptera are valued for their beauty and a few are useful in pollination,
commerce such as silkworm, as the sericulture industries which are totally depends
upon the products of moth (i.e. cocoon formed during pupal stage). But majority of
moths are probably more destructive to trees, crops, fruits and store grains in the
larval stage than other group of insects. However, many species of moth have turned
declining partially due to human activity and use of insecticides and pesticides by
farmers.
Biodiversity is one of the important cornerstones of sustainable development
and represents the biological wealth of a given Nation. The world is currently facing
its greatest ever biodiversity crisis. Insects and plants are becoming extinct because
of habitat loss, over-exploitation, pollution, overpopulation and the threat of global
climatic changes (Murugan, 2006).
1.2
MOTHS AS A STUDY GROUP
Lepidoptera is a group of insects that contains many large and showy species.
Among these, butterflies have received much attention from the average layperson
due to their diurnal activity and colourful wing patterns. Consequently the
conservation of butterflies is much better than any other group of insects (Wang &
Fang, 2007).
1.2.1
MOTHS – A DIVERSE FAUNA
Insects and other animals often live in more or less specialised niches.
Increased specialisation enables a species to adapt very efficient exploit, a small
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niche. On the other hand, the advantage of being a generalist is that a much larger
population may be maintained through the use of a wide variety of resources.
Specialists may be less vulnerable to predation and generalists less vulnerable to
extinction. So, in stable habitats many moths will become much specialised
(Zborowski & Edwards, 2007). Small animals can inhibit very small niches than
large ones; as the complexity of an ecosystem increases there will be more and more
different small niches form of those will be quite rare in occurrence. The larval
stages of moths successfully occupy a wide array of small niches (Kendrick, 2002).
Insects particularly the moths have taken advantage of vast number of rare small
niches and this is the reason for such huge diversity. Recent estimates reveal the
report of over 127,000 species of moths from the world, of which over 12,000
species are recorded from India (Chandra, 2007). 789 moth species have been
recorded from Maharashtra state, principally from Pune, Satara, Mumbai &
Khandala (Cotes & Swinhoe, 1887-89).
1.2.2
ECOLOGY OF MOTH
Moths are an integral part of most of the ecosystem (Srivastava, 2002). They
are also monitored to indicate climatic changes and environmental degradation. Thus
like other animals, moths are now studied as living ecological components. Most
species of moths consume plant material, both living and decaying, in all manner of
ways – (Stem borer) eating inside stem, eating flowers, fruit, roots, bark, leaves
(Friedrich, 1986; Porter, 1997; Robinson, et al. 2001; Kendrick, 2002; Sharma, &
Ramamurthy, 2010). Some species known to feed on forms of keratin such as animal
fur (Robinson, 1990; Gerard, 2002), and a few species are parasitic or predatory
(Kato, 1940; Montgomery, 1982). This ability to utilize a wide variety of food
sources has allowed moths to survive in virtually every habitat on Earth (Kendrick,
2002). As many species of moths known to be pest of forest, agricultural crops and
grass fields reasonably detailed studies of pest species are necessary if they are to be
controlled efficiently. The more that is known about the diversity, ecology and
biology of a pest then more options available for their control methods that do not
involve synthetic chemical, can be more precisely targeted to a particular pest, and
are more eco-friendly. Such studies require biological research on the pest and also
require research enabling a particular pest to be distinguished reliably from other
pests and innocuous species. The most serious moth pests of crops are two very
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similar species of Helicoverpa (Noctuidae); methods found in the 1950s to
distinguish these and similar species still underpin all research into the control of
these moths (Zborowski & Edwards, 2007). Even where insecticides are used that
may be effective against two very similar pests, insecticidal resistance will develop
independently in each and there will also be differences in biology.
1.2.3
ROLE OF TAXONOMY IN CONSERVATION OF MOTH
In conservation it is also important to accurately distinguish species. An
endangered or threatened species can only be listed if it is clearly distinguished from
other very similar species. Knowing what moths contributes and what they do is
important in understanding the natural functions of moths in ecosystems, for
example, pollination, nutrient recycling, food for other organisms, and control of leaf
litter and plants (Zborowski & Edwards, 2007). Night-blooming flowers usually
depend on moths or bats for pollination, and artificial lighting can draw moths away
from the flowers, affecting the plant‟s ability to reproduce. Taxonomic study on
moths is essential to have a single internationally agreed name for each moth. The
system that we use is the closest thing to an international language. A name is
essential without it no knowledge can be accumulated or communicated about
moths.
1.2.4
PHOTO-TACTIC BEHAVIOR
The attraction of many insects to light is a well-known phenomenon. The
physiological reasons for this is still not fully understood, but traditionally various
theories involving the dazzle effect of light were proposed. Accordingly, most of the
moths are attracted to light at night in the near ultraviolet range of wavelength 360
nanometres, which is just beyond the range of human vision. According to
astronomers there is very little ultraviolet light available at night, yet moths can still
detect this (Zborowski & Edwards, 2007). It has been shown that moths are strongly
attracted to a point source of light than to a panel of same luminosity. Possibly moths
may also orient on the horizon when in flight, at least in open situations except for
the face of moon, the brightest part of the night sky is said to be just above the
horizon and if this is true in ultraviolet then moths could orient themselves by
viewing the ultraviolet light just above the horizon.
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Though light trapping does not attract all the nocturnal moth species but this
method frequently used to sample data of relative abundance and distribution of
moths using UV emitting light sources such as mercury vapour and actinic lamps
(Waring, 1994, Young, 1997; Leverton, 2001). The method has drawbacks that many
species are not consistently attracted to UV light (Hsiao, 1972; Mikkola, 1972;
Waring, 1994). The more powerful mercury vapour lamps catch a much larger and
richer sample, while the actinic lights have a more effective catch in a small area,
especially for Geometridae (Walker & Galbraith, 1979). Lunar cycles also have
significant effect on attraction of moth towards light as there is less number of moth
catches in bright moon light as compare to moonless nights gives good number of
catch (Siddorn & Brown, 1971; Bowden, 1973; Bowden & Church, 1973; Persson,
1976; Frank, 1988; Waring 1990, 1994).
1.3
SEASONALITY
Occurance and population of any living organism has greatly influenced by
environment that includes biotic and abiotic factors; i.e composition of flora and
fauna determined by climatic conditions (Beeson, 1941). Climate and weather
conditons directctly or indirectly affect the abundance of insect species in particular
area. Climatic factors such as rainfall, snowfall, temperature, humidity; wind flow
and sun light are influences flora of that area which determines insect seasonality
and abundance. Although all these factors work together; it may show primary
effects on insect seasonality individually. The action of temperature is persistently
modified by the relative atmospheric humidity at the instant and changes in these
two factors often occur in opposite directions. As air temperature rises, its humidity
increases. Very high air-temperatures may be accompanied by extreme dryness or by
saturation, but air at low temperature to which insects are ordinarily exposed is
moist. Rainfall is responsible for decreasing atmospheric temperature and raising
humidity. Moth species richness in India is related to high rainfall that has enormous
diversity; while low rainfall and dry areas comparatively has low diversity with less
species number (Scott, 1983). According to Bell & Scott (1937), the abundance or
rarity of individuals is very variable. Individuals of some species are always
common, of others always rare. A usually uncommon species may appear in great
numbers in certain seasons, or may be locally abundant in a part of its range.
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1.4
REVIEW OF LITERATURE
The moth fauna of India is poorly known. Prior to this study there has been
only few survey have carried out before 20th century in British administration
especially in Maharashtra state. Fabricius and Cramer initiated studies on Indian
Lepidoptera in 1775 (Hampson, 1892). Frederick Moore brought out a magnificent
publication Lepidoptera of Ceylon in 1890-92, covering both the Moths and
Butterflies of Sri Lanka and the first volume of Lepidoptera Indica was published in
1890. Both these publication are till date among the finest and most comprehensive
works on Lepidoptera. The moths of Bombay, Poona and other localities in western
India have been largely worked by Col. C. Swinhoe in 1885 that has made very large
Indian collection. The moth fauna of Nilgiris was studied by G. F. Hampson in 1891
who contributes his work to the fauna of British India and recorded about 611
species of moths particularly from Maharashtra. Moore in 1867 published the
lepidopteron insects of Bengal in the proceeding of Zoological Society of London.
Leech J. H. in 1937 also made the large collection of moths from Kashmir; he also
contributes to Japanese and Chinese collection (Hampson, 1892). The moths of
North West Himalaya were collected by the Rev. J. H. Hocking in 1890 which is
now in the British museum (Hampson, 1892).
In Assam and Burma region the fine collections made by W. Doherty in 1969
upper Assam; the Naga hills and they presented their collection to British museum
(Hampson, 1892). The moths of Dharmashala and Meean meer, Punjab, Nilgiris are
reported by Hampson in 1895. The moths found in Raipur and Bombay is reported
by Swinch. Gardner in 1941 reported immature stages of Indian lepidopteron
Noctuidae, Hyspiridae to Indian forest research entomology.
South-East Asia is one of the rich biodiversity areas on the earth; more than
6000 Micro-Lepidoptera species are known (Robinson, et al. 1994). Moths of Borneo
series in 18 parts published by Holloway, J.D., includes 3629 species covering the
area of 743,330 sq. km. Srivastava, in 2002 studied Noctuid moths from Himachal
Pradesh and published a book „Taxonomy of moths in India‟. The moths from sanjay
Gandhi National park, Boriwali, Mumbai were studied by Vaylure Subhalaxmi in
2003. Ghosh in 2003 studied the Geometrid moths of Sikkim and reported 525
species, wherein record of 460 and 260 species of Geometrid moth from Meghalaya
and West Bengal respectively was mentioned. Mathew et al. in 2004 catalogued 202
species of butterflies and moths from shendurny wildlife sanctuary, Kerala.
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Rose & Pooni (2004, 2005) recorded 18 species belonging superfamily
Pterophoroidea and 16 species belongs to superfamily Tortricoidea from North
western part of India. Chandra in 2007 studied moth diversity of Madhya Pradesh &
Chhattisgarh 142 species of moths from 90 genera and 16 families. Gurule et al. in
2010 cataloged 70 species of moths of family Noctuidae from Nashik district of
Maharashtra. Sidhu et al. in 2010 documented 109 species micro lepidopteran moths
from family Pterophoridae in online version of Zoological Survey of India.
1.5
OBJECTIVES
Review of literature reveals that study on diversity of moths from North
Maharashtra is not yet done so far. Whatever work carried out on diversity of moth
in Maharashtra was done before 1950 so; it is need of time to carry out such kind of
research work for this area. Present work is undertaken to know the taxonomic status
of moths from North Maharashtra. Site survey (North Maharashtra) undertaken as
need for Environmental Impact Assessment (EIA) or to prevent the destruction of
sites threatened by smaller developments.
Aims and Objectives:
1. Find out the patterns of biodiversity of moths for study area by extensive survey
and taxonomic study; it will form catalogue of moths for the first time.
2. Seasonal patterns with the abundance and species richness is studied using
diversity indices by statistical application.
3. To establish a foundation for research on moths and provide a scientific data to
forest dept. & wildlife for evaluating the threatened and endangered species
values for their conservation in future.
To reach at aim the study was conducted during the more than three years
period from February 2009 to January 2012. More efforts have been taken for
precise identification of the collected voucher moth specimens. No attempt was
made to describe the seasonality of individual species, as the objective was to
evaluate the general seasonality of moths in the area.
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