Beneficial and Harmful Insects and Economics Importance Of Insects.

 BENEFICIAL AND HARMFULL INSECTS

• Beneficial  insects

Plant pollinators (Bees, wasps, butterflies, moths, hoverflies, beetles)

Many plants rely on insects to spread pollen while they are foraging. Insects are drawn to plants in a variety of ways, including by providing pollen or nectar as food and by employing scent and visual cues to direct them to the flower. As a result, plants and insects have close interactions. In the US alone, the value of crop production caused by native insect pollination is estimated to be around $3 billion.

Honey bees and butterflies are the first insects that come to mind when we talk of pollinators, but many other insects also carry out this function for flowering plants. There are flies, wasps, beetles, and even certain other insects, such Hemiptera and thrips, that most people are unaware of. The orders Hymenoptera (bees, wasps, and ants), Lepidoptera (butterflies and moths), Diptera (flies), and Coleoptera all have numerous significant pollinating insect species (beetles).

These insects consume floral nectar and pollen as adults. By moving pollen from an anther to a stigma, they can start pollination as they forage from plant to plant. Female bees and pollen wasps actively collect pollen and nectar onto their bodies to supply their nests with. The pollen and nectar are then consumed by their larvae. Yucca moth larvae consume the seeds of yucca plants rather than pollen or nectar. To ensure good seed germination for their children, the adults pollinate the yucca plant by aggressively gathering pollen onto their palps and then applying the pollen to a receptive stigma.

Worldwide, insect pollination is estimated to be worth $217 billion in economic terms.

(2008) (Science Daily, September 15). German researchers discovered that the pollination services given by insect pollinators, primarily bees, were worth USD 153 billion to the world's primary food crops in 2005. This figure represented 9.5% of the value of all food produced through agriculture worldwide. The study also found that the elimination of pollinators would result in consumer food losses between $190 and $310 billion.

Predator's of pest

(Dragonflies, beetles, bugs, wasps, and lacewings)

Beetles, true bugs, lacewings, flies, midges, spiders, wasps, and predatory mites are some of the arthropods that prey on insects and mites. Predators of insects are present in all parts of plants, including those that are underground, as well as in surrounding shrubs and trees. Others are generalists, while some predators are specialists in the prey they choose. Some are incredibly helpful natural pest bug enemy. Unfortunately, some prey not just on pests but also on other helpful insects.

Major Characters of arthropods predator's 

• Generalists rather than specialists are frequently found in adults and immature stages.
• Typically, they are larger than their prey.
• They kill or eat a lot of prey.
• Predators can include adults, immature stages, males, and females.
• They attack both adult and immature prey.

Lady beetles, ground beetles, rove beetles, flower bugs and other predatory true bugs, lacewings, and hover flies are among the significant insect predators. Insect and mite pest predators include spiders and some mite groups. Natural enemies are crucial in controlling possible pest populations. We've seen what happens when insecticides annihilate a pest's natural adversaries. Surveys of agricultural systems provide a hint as to the kind and probable quantity of predators that may attack a crop.

For instance, among 45 insect groups and 23 families of spiders and mites, there are almost 600 species of predators that have been identified in cotton. In potatoes in the northeastern United States, 18 species of predatory insects have been identified (excluding spiders and mites).

Parasites of pest (Diptera and Hymenoptera)

Insects called parasitoids have an immature stage that grows on or inside an insect host and eventually kills the host. Adults tend to live on their own and can be predators. Additionally, they might consume pollen, honeydew, or plant nectar as food sources. Many parasitoids are restricted to one or a small number of closely related host species because they need to adapt to the life cycle, physiology, and defences of their hosts. An estimated $4.5 billion in crop losses are prevented by helpful insects that are either predators or parasites of agricultural pests. The following categories contain the most valuable insect parasites:

• Fly Tachinids (Diptera)

• Wasps with ichneumons (Hymenoptera)

• Brucid Wasps (Hymenoptera)

• Wasps, Chalcid (Hymenoptera)

When the parasite has finished developing, the host insect pest that the parasite lives in or on is killed. The immature stage lives on or inside a host and kills the host before the host has finished developing. Parasite (also known as parasitoid) adults are free-living. The eggs are either inserted inside the host or one or more are laid outside the body of the host. The developing parasite feeds on the host and needs just one piece of prey to develop fully.

Adults that live independently may consume plant nectar or draw nourishment from host insects by piercing their bodies and sucking out their fluids (host-feeding). Because many parasites have a smaller host range, only need one host to finish developing, have a strong capacity to find and kill their host, and can react quickly to changes in host numbers, parasites are frequently thought of as more effective natural enemies than predators.

Economic Importance Of Insects 

Greater investment in the conservation of these services is warranted given that the estimated yearly value of the ecological services provided by insects in the United States alone is at least $57 billion. Human life on Earth would eventually become extinct if insects weren't active. Although more than a lakh species of insects are known to exist today, there are undoubtedly a million or more.

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