Indigenous Insect Species Of Pakistan

Insects appeared on earth over 480 million years ago and have been evolving ever since into the largest, most diverse, and most successful group of organisms in the world.

The term entomology  is derived from the Greek  words “entomon,” which means an insect, and logos, which means to study. The term “insects” is derived from the Latin word “insectum,” which means “cut into.” The branch of science that deals with the study of species of insects is called entomology.

Insects appeared on earth over 480 million years ago and have been evolving ever since into the largest, most diverse, and most successful group of organisms in the world.

Arthropods comprise a phylum, or group of animals, with jointed legs and an exoskeleton covering soft internal organs. Insects are invertebrates, belongs to phylum Arthropoda, class Insecta, comprising small, air-breathing having the body divided into three parts head, thorax and abdomen having three pairs of legs and usually of two pairs of wings. Among 1.7 million living specie,0.95 million species are insects.

• Phylum-Arthropoda
• Class-Insecta

General Characteristics of Insects Species:

• Insects are invertebrates.
• Insects have a segmented body, and these segments are grouped into 3 regions: the head, thorax, and abdomen. This grouping of segments in insects is called tagmatosis.
• Insects have an exoskeleton made up of a material called chitin.
• Insects have three pairs of legs and are thus classified as hexapods.
• Insects grow into different stages of life by a process called moulting.
• One pair  of antennae functions as sensory organs in which the antennae are absent (order prestura).
• One pair of compound eyes and one to three pairs of ocelli (sometimes absent) may be present.
• Mouthparts are variously adapted depending on the mode of feeding.
• Breathing is done through the tracheal system.
• The circulatory system is open type and therefore contains hemoglobin, a blood like substance.
• They excrete uric acid through the Malpighian tubules.
• The nervous system includes a cricopharyngeal ring and a ventral nerve cord.
• Insects have bilateral symmetry.
• There is a tubular alimentary canal with the mouth and anus.
• The heart in insects, i.e., the pumping organ, is present dorsally.
• Insects have a dorsal brain with a ventral nerve cord.
• The muscles in insects are striated muscles.
• Insects do not have cilia.
• Insects have paired, segmented appendages.

Habitat

Insects are adaptable creatures that live in almost every habitat on earth. They live in hot deserts, freshwater streams, tropical rain forests, up snowy mountains, and, of course, in your own garden. While some insects do live in water, about 97% of insects’ habitats are on land.

Reproduction

Nearly all insects reproduce by sexual reproduction. This involves the formation and fusion of gametes. Sperm for tests and eggs from the ovaries. There are some insect species that can also reproduce asexually. They do this through a process called parthenogenesis. During parthenogenesis, a female’s egg can produce a new organism without being fertilized by sperm.

Metamorphism

Eventually, insects’ moult for the last time and emerge as adults. The changes in form that occur as an insect approaches adulthood. When the immature insects and the adults are similar in appearance, the process is called simple metamorphic change. The immature insects during their development are called nymphs.

After the last larva, the insect changes into a pupa. Insects that cannot undergo a metamorphic change during their development are called ametabolous insects, including members of the apterygote subclass and plecopteran infraclass. The only changes that these species undergo are an increase in size and the maturing of sexual organs. Among insects that experience metamorphosis, there are two types:

• Hemimetaboly(Superorder Exopterygota)
• Holometaboly  (Superorder Endopterygota)
• Hemimetabolous:

Insects such as cockroaches, grasshoppers, and dragonflies go through gradual changes as they slowly develop from juvenile forms called nymphs to adult forms. These changes often include the budding and growth of their wings.

• Holometabolous:

Holometabolous complete metamorphosis. With the characteristics of beetles, butterflies, moths, and flies and wasps, their life cycle includes four stages:

• Egg
• Larva
• Pupa
• Adult

Economic Importance of Insects:

Species of insects have tremendous economic importance. Some insects produce useful substances, such as honey, wax, liquor, and silk. Honeybees have been raised by humans for thousands of years for honey. The silkworm greatly affected human history.

When the Chinese used worms to develop silk, the silk trade connected China to the rest of the world. Adult insects, such as crickets, as well as insect larvae, are also commonly used as fishing bait. Insects are important for pollinating crops.

We use insects for food, as a food source themselves in some countries, and to recycle nutrients by decomposing dead material to recycle nutrients. Insects are also important because of the damage they can cause to humans. Some insects spread diseases; others can decimate our food supply.

In terrestrial ecosystems, insects play key ecological roles in diverse ecological processes such as nutrient cycling, seed dispersal, bioturbation, pollination, and pest control. As the dominant form of animal biomass and life on earth, insects represent many different trophic niches and a wide range of ecological functions in their natural ecosystems, including herbivory, carnivory, and detritus feeding.

Insects are the key components in diverse ecosystems and major players in the functioning of ecosystem processes. Since insects are perceived as potential pests, this ecological importance includes ecosystem cycling, pollination, predation/parasitism, and decomposition.

Pakistan Topography

They may fly to different places, but they still primarily live on land. Pakistan is located between longitudes 60 degrees and 77 degrees east and latitudes 23 degrees and 37 degree North stretches for 1600 kilometres from north to south and 885 kilometres from east to west, for a total area of 796,096 kilometers2.

The annual rainfall in the plains is 125mm, while in the mountains it ranges from 500 to 900mm. The country has a semiarid, tropical, and subtropical climate, with summer temperatures reaching 40 degrees Celsius and winter temperatures falling close to freezing.

Pakistan has fauna in abundance such as Ethiopian, Oriental, and Palearctic, which represent coastal areas of Sindh, Rajasthan (India), China, Afghanistan, and Russia. Agriculture is the backbone of this country, but unfortunately all-important crops, plants, and stored products are infested by known and unknown pests, resulting in a valuable economic loss every year.

This sector plays a key role in the economic development of the country as well as providing food to people and contributing a considerable share of foreign exchange. The topography and climatic conditions of this country are favourable for insects’ biodiversity.

Insects of Agricultural Importance

For as long as humans have practised crop agriculture, pests have occurred on their crops, and insects have been predominantly perceived as competitors in the race for survival. The insect-plant relationship is the dominant biotic interaction, and approximately 50% of insect species are herbivorous, with most herbivorous species feeding on plants in one or a few related plant families.

Herbivorous insects damage 18% of world agricultural production, and this is mainly controlled by chemical methods. Despite these damages, less than 0.5% of the total number of known insects species are considered vital for human survival because crops cannot be produced without the ecosystem functions provided by insects.

Around 72% of the world’s crops are dependent on insects for pollination. Pollinating insects improve or stabilise the yield of three-quarters of all crop types globally—one third of global crop production by volume.

A variety of insect taxa have been linked with increasing seed set. Insect pollinators include hundreds of species of solitary bees, bumble bee flies, beetles, and butterflies, and in several crops, some species will be more important for pollination than the honeybee, Apis mellifera. Global pollination by insects is estimated to contribute 9.5% to the yield of crop production. Pest control is an evitability in agriculture.

Predatory insects contribute  significant ecosystem functions by controlling pest insects in cultivated crops. In 75% of field studies, it was indicated that generalist predators reduce pest populations in arable farmlands significantly, with ground beetles among the dominant generalist predators in arable crops and effectively reducing the population size of economically significant agricultural pests such as aphids, slugs, and not feeding flies but phytophagous beetles.

Species of insects are also important in improving agricultural soil. Through their activity in the soil, dung beetles increase the nitrogen, phosphorous, potassium, calcium, magnesium, or total protein content of the soil, which significantly elevates the yield of wheat plants relative to chemical fertilisers.

This article is jointly authored by Ayesha Fatima, Komal Arshad, Hammad Ur Rehman Bajwa and Muhammad Kasib Khan