Integrated Pest Management (IPM) is an effective and environmentally sensitive approach to pest management that relies on a combination of common-sense practices. IPM programs use current, comprehensive information on the life cycles of pests and their interaction with the environment
DEFINITION OF INSECT ECOLOGY AND INTRODUCTION TO ENVIRONMENT
AND ITS COMPONENTS
Ecology
The term ecology is derived from the Greek term “oikos” meaning “house” combined
with “logy” meaning “the science of” or “the study of”.
Definition of Ecology
Ecology is the science of inter-relations between living organism and their
environment including both the physical and the biotic environments and emphasizing inter
species and intra species relations. (Allee, 1949).
Eugene P.Odum (1953) defined ecology as „the study of the structure and functions of
nature (or Environmental biology)‟. He is the Father of Modern Ecology.
Andrewartha (1961) defined ecology as the scientific study of the distribution and
abundance of organisms.
Krebs (1972) modified the definition as: Ecology is the scientific study of interactions
that determine the distribution & abundance of an organism.
Ecology is divided mainly into „Autecology‟ and „Synecology‟. Autecology is the
study of individual organisms or an individual species in relation to the environment while
Synecology is the study of the group or groups of organisms associated in a community in the
same environment i.e., in relation to various other species living in the same environment.
Ecology related terminology
Habitat: Habitat is the place where the organism lives. Provides the kinds of food and
shelter.
Population: Population denotes groups of individuals of any kind of organism. A group of
individuals or a species occurring in a given area or locality at a specific time.
Community: Populations of different species live together and form a community, meaning
all population in the area at a specific time. The community is influenced by its physical
environment. It includes all the population of a given area.
Ecosystem: An ecosystem is a biological community of living organisms that live and
interact with each other in a specific environment.
,Biosphere: Biosphere is the term used for all of the earth‟s ecosystems functioning together
on the global scale.
Insect Ecology:
It can be defined as the understanding of physiology and behaviour of insects in
relation to their environment.
It is also defined as the scientific study of insects, individually or as a community
which interact with the surrounding environment or ecosystem.
Agro-ecosystem
It is a man created and maintained ecosystem to satisfy the nutritional needs of
humans. In Insect ecology, Agro-ecosystem is the basic unit of pest management. An agro-
ecosystem is composed or more or less uniform crop-plants population, weed communities,
animal communities (including insects), micro-biotic communities and various physical
environments like temperature, humidity, rainfall, microclimate that react with it. The
complex system of biotic and abiotic factors constitutes an Ecosystem. Whereas the crop,
insects, other animals and the physical abiotic factors together constitute an Agro-ecosystem.
Unique features of Agro-ecosystem
Dominated by plants selected by man
No species diversity and no intraspecific diversity. Genetically uniform
Phenological events like germination, flowering occur simultaneously
Lack of temporal continuity - due to various agricultural operations carried out by
man like ploughing, weeding, pesticide application etc.
Plants contain imported genetic material
Nutrients are added in the form of synthetic fertilizers
Outbreak of pests, weeds and diseases occur frequently, due to natural tendency called
Balance of nature.
Ecosystem processes:
Insects play important roles in ecosystem processes, as the list below indicates.
Insect herbivores convert plant and algal biomass into animal biomass
Insects then become important food sources for primary carnivores, including many
other insects and vertebrates such as reptiles, amphibians, birds and mammals. Insects
are vital components in moving energy up the food chain and food web
, Insects as herbivores and saprophages play a role in decomposition of plant biomass
and its recycling of energy and nutrients.
Insects have been used extensively as agents in the biological control of other insects.
Herbivorous insects also can have strong impacts on plant populations, either killing
plant individuals or weakening them, thereby altering plant community composition
and diversity.
Pollination by insects is another essential function, for many plant species depend
entirely on insects to transport pollen from one individual to another.
Decomposition is also accelerates in animal corpses by colonization by flies, burying
beetles and others. These kinds of insects contribute important to the hygiene of
natural landscape.
Insects are critical in vectoring diseases of plants and animals. Many plant diseases
are transmitted, especially by sucking insects. Serious diseases in animals, wild and
domestic, and humans are transmitted by insects like ticks, mite, mosquitoes, tabanid
flies, black flies, bedbugs, fleas and assasian bugs etc.,
Agro-ecology and insect pest management:
Indiscriminate uses of insecticides lead to a regular resurgence of pest due to the fact
that the natural enemies viz., insect parasitoids and predators are being killed. The increase in
pest population is also due to the interference of man by monoculture, use of high
nitrogenous fertilizers etc. Because of which the balance of life in nature gets upset and the
pest appears in severe form every year. The importance of ecology was then felt and
integrated approaches in pest management are now made to avoid the violent fluctuations in
pest populations.
Ecological studies assist pest control programmes by explaining pest problems and
suggesting alternate ways of combating insects. The outbreaks of the pests can also be
predicted. The ecological studies investigate the causes for the changes in population number
help to integrate the various methods of control, without disturbing the balance of nature. The
pest surveillance programmes form a part of ecology. Forecasting of the possible attack by
different pests can be done and accordingly the control measures can be initiated in time.
Suitable chemicals can be selected depending on the presence or absence of natural enemies.
As such ecological studies form a basic part of the approach to the integrated pest
management (IPM).
, As emphasized by Geier (1966), the pest management programme should include:
Study of factors determining the need to modify the life-system of a pest with
a view to reducing its numbers below the economic threshold
Study of applied ecology which involves application of biological knowledge
and the available technology for achieving the desired modification
Devising pest control procedures that suit the available technology and are
compatible with the economic and environment quality requirements.
Introduction to Environment:
For making a scientific approach to the study of ecology at all the levels viz.,
individual, population, community and ecosystem, it is essential to understand the various
factors of the environment. Climate constitutes the physical factors which exert their
influence on all the organisms. Food and other organisms of the same and other species are
the other important factors. The environment refers to the surroundings of an organism or
species or sum of everything that affects the organism.
Components of Environment
1. Biotic factors known as Density dependent factors
a. Food and b. Competition c. Predators d. Parasitoids and e. Host plants
2. Abiotic factors known as Density independent factors
a. Temperature
b. Humidity
c. Rainfall
d. Light
e. Air
f. Water
g. Soil etc.,
The various components of the environment exert their influence on the
population in different ways, leading to fluctuations in numbers within certain lower and
upper limits. In Some species, the upper limit corresponds to its status as a pest, i.e the level
at which it causes economically significant damage to a crop. The degree or the nature of
damage caused may however, vary according to the type of pest and its intensity (Atwal and
Singh, 1990). All the components act through the pathways of natality, mortality and
dispersal.
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