INSECTS AS POLLUTION INDICATOR

Submited ToDr. Amritpal Singh Kaleka

Presented by:Rahul Ranjan

Department of Zoology and Environmental Sciences

Punjabi University, Patiala

WHAT IS POLLUTION ? Pollution is addition of harmful substances (solid,

liquid, gaseous and even light) to the environment which has negative effects.

These effects are like degradation of natural resources and nature.

Effects of pollution are slow and gradual but last long.The major types of Pollution are as follows:

I. Water PollutionII. Terrestial Pollution III. Air PollutionIV. Noise Pollution andV. Light Pollution

WHAT IS BIOINDICATOR ?

Species of an ecosystem which can be used to study or assess ecological performance and sensitive against changes in their environment, called as bioindicator.

They indicate or show how changes are taking place and are used to monitor the overall health of an ecosystem.

Bio-indicators can tell us about the cumulative effects of different pollutants in the ecosystem.

INSECTS AS BIOLOGICAL INDICATOR Insect is an organism with three pair of legs,

body is divisible into three parts (head, thorax and abdomen) and presence of compound eyes.

Insects are used as bio indicators because they are the most abundant animals in almost all ecosystems and can be used to evaluate the impact of environmental changes.

o It respond quickly to environmental changes and show high sensitivity for detecting early changes in their geographical area.

HOW ARE THEY USED ?oDifferent bioindicators are sensitive to different types of changes, it is being used as following categories:

BIO-INDICATOR GROUPS OF INSECTS

1. Dragonflies and damselflies

2. Mayflies3. Caddisflies4. Bugs5. Stoneflies6. Honey bees7. Beetles

8. Collembolans9. Butterflies and

Moths 10.Ants 11.Syrphid fly

INSECTS AS WATER POLLUTION INDICATORo Insects which live completely or carry a

major part of their life cycle in water can tell directly about water pollution.

o Larvae of mosquitoes, odonates and neuropterans can only live in fresh water. Absence of these larvae indicate towards presence of Arsenic and Lead concentrations in water.

o Several aquatic insects groups can be used as aquatic environment bioindicators, which is as followes:

DRAGONFLIES AND DAMSELFLIES Dragonflies and damselflies

(known collectively as the “Odonata”) are an important group in biological water quality monitoring, as they are particularly sensitive to pollution.  

MAYFLIES

Mayflies (Ephemeroptera) larvae are recognized worldwide for their sensitivity to oxygen depletion in running waters, and are therefore commonly used as bioindicators in many monitoring programs.

CADDISFLIES Caddisflies (Trichoptera) are the

group of insects whose larvae occur in all types of fresh water. Particular species are sensitive to water pollution and that’s why they are used as bio indicators of water purity.

STONEFLIES

Stonefly (Plecoptera) larvae can only live in clean water, these flies indicate high oxygen water.

BUGS

Bugs belong to order Hemiptera, many families like Corixidae, Nepidae, Notonectidae, Pleidae, Belostomatidae, Gerridae, Veliidae and Mesoveliidae are also act as bioindicator to determine the quality of water.

oLand insects are good bioindicators in various types of environmental change.

oOccurrence of excess acidic or alkaline content, fertilizers or industrial waste kills larvae, nymphs and adults of these insects.

oPolluted land areas are not fit for insects to lay eggs.

oSeveral insects groups can be used as terrestrial environment bioindicator, which is as follows:

INSECTS AS TERRESTRIAL POLLUTION INDICATOR

BEETLES The Order Coleoptera is the largest

order of class insecta and plays roles in maintaining soil quality, and contributes to the physical and chemistry soil formation.

They also participate in biological control and biological monitoring of pollution from oil, Sulphur, Carbon dioxide and insecticides.

COLLEMBOLANS Collembolan are primitive insects that have

influence on soil fertility by microbial activity stimulation.

They are very sensitive to change in soil caused by pollutant such as heavy metals, pesticides and soil acidification in agricultural crops.

ANTS

Ants are very sensitive to human impact, and could be used as environmental indicators in different ecosystems depending on the degree on environmental change, and these changes reveals the extinction of many ant species.

INSECTS AS LIGHT POLLUTION INDICATOR

Excess exposure to light disturbs the developmental cycle of many insects. Their daily activity regime or biological clock is negatively effected.

Heavy flash lights at night have already disturbed life cycle of moths and may flies. Under effect of such light these insects have lost their orientation cues to search for host plants.

The monarch is the only butterfly known to make a two-way migration like birds. They use a sophisticated navigation system to guide them in their journey south for the winter. Research has shown that exposure to artificial light can disrupt their navigation system, disorienting them from their migration routes.

INSECTS AS SOUND POLLUTION INDICATOR Sounds are an important part of social

insects life history. Generally males produce advertisement calls to attract females or to drive out competitive males out of their territory.

Negative effect of vehicular horns, noise of moving vehicles and other sources suppress the advertisement call of male insects hence destroying their mating cycle and thus decreasing their numbers.

Sound pollution has extreme negative effect on cicadas, crickets, locusts and grasshoppers mainly.

INSECTS AS INDUSTRIAL POLLUTION INDICATOR

Industrial pollution pollutes the entire ecosystem as whole.

Unprocessed industrial output, when enters ecosystem leads to a phenomenon called biomagnification.

Biomagnification – When a carcinogenic or toxic substance is consumed by primary trophic unit and consequently reached every trophic level in a food chain with increased potency. Thus, hampering the complete system.

oFamous example of effect of Industrial Revolution on moths is British population of Biston betularia.

INSECTS AS AIR POLLUTION INDICATOR Air pollution blocks trachea/spiracle

openings of insects.

Orientation cues of insects to search host plant, mate or ovipositional sites are damaged.

Several insects groups can be used as air pollution indicators, which is as follows:

HONEY BEES The honeybees

(Hymenoptera) act as bioindicators of environment in two ways as it signals via high mortality rates due to the presence of toxic molecules or via residues in honey, pollen and larvae the presence of heavy metals.

Recent mass dying out of Honey Bee in United States of America because of fertilizers has brought Honey Bee to list of endangered species.

LEPIDOPTERANS Some lepidopteran groups are used as

environmental indicators by heavy metals and carbon dioxide concentration in locations close to industrial and even within urban areas.

Presence and consequences of copper, iron, nickel, cadmium, and other substances used in fertilizers were studied with pupae of different Geometridae and Noctuidae species, cycle duration and mortality rate of newly hatched butterflies larvae which feed on plants subjected to high CO2 concentrations.

SYRPHIDFLY These flies belong to family Syrphidae,

one of the largest family of Diptera has wide distribution and well known taxonomy and its larvae require different environmental conditions, which make these flies good bio indicator.

CONCLUSION The use of bioindicators is essential for

environmental monitoring.

The main characteristics of a bioindicator are: richness and diversity species, ecological faithfulness, fragility to small environmental changes and good organism responses.

Class Insecta has all of them. Therefore, this study concluded that the Class Insecta has many potential representatives that can be used as environmental bioindicators.