Role of Insects in Agriculture

Sufficient food production for a growing human population has become an issue of global concern. Almost all of the world’s fertile land is currently in use and arable land areas cannot be expanded significantly. The global challenge is to secure high and quality yields and to make agricultural production environmentally compatible. Insects have been hugely successful in terms of both species richness and abundance. Insects make up the most numerous group of organisms on earth, around 66% of all animal species, and being good dispersers and exploiters of virtually all types of organic matter, can be found almost everywhere, forming an important part of every ecosystem and are vital within our food supply chains performing valuable ecosystem services.
Insects have been predominantly perceived as competitors in the race for survival. Herbivorous insects damage 18% of world agricultural production. Despite this damage less than 0.5 percentage of the total number of the known insect species are considered pests. Insect pests are created through the manipulation of habitats by humans, where crops are selected for larger size, higher yields, nutritious value, and are cultivated in monocultures for maximum production. This provides a highly favourable environment for the population increase of herbivorous insects. To ensure stable crop yields we need to change the management strategies of agro ecosystems. We need to manage these systems in such a way that insects performing valuable ecosystem services are also incorporated into the system. This will ensure stable, resilient and sustainable systems in a constantly changing environment and will go a long way to ensure future food security.
In homogeneous habitats such as fields, insect communities can be fully recorded more quickly than in diverse, near-natural habitats. Agriculture’s impact on insect diversity is more severe than previously thought, according to a new study. It has long been known that agriculture contributes to the decline in insect biodiversity. The loss of host plants, frequent mowing, and pesticide use all deprive many species of their habitats. Insects play a multifaceted and vital role in agriculture, contributing to both crop production and overall ecosystem health. They are essential for pollination, pest control, soil health, and nutrient cycling, making them crucial for sustainable and productive farming practices. Over three quarters of wild flowering plant species in temperate regions need insects for pollination and about two thirds of all plant species rely on insects for pollination. The most important pollinators are bees, beetles, butterflies and flies. Insects therefore contribute to plant diversity and affects animal biodiversity through pollination indirectly.
Now, a research team has discovered—using innovative analytical methods—that the impact of agricultural land use on insect diversity is even more dramatic than previously assumed. The findings are based on an analysis of insect species from 400 families collected across a wide range of habitats One surprising outcome is that a higher proportion of the actual species present in agricultural areas was detected, compared to the more diverse, near-natural habitats. In other words, sampling in farmland was more complete. After adjusting for these differences, the researchers identified a decline of up to 44% in total insect species diversity in agricultural landscapes. But that’s not all; for the first time, the new methods also revealed a loss of nearly 30% in evolutionary diversity—that is, the range of evolutionary relationships among species. This suggests that previous studies have likely underestimated the impact of agriculture on insect diversity—due to two key reasons. First, because the completeness of insect community sampling in farmed landscapes is much higher, making differences appear smaller than they actually are. And second, because little data has been available on phylogenetic—or evolutionary—diversity at this scale until now. The new method allows researchers to systematically capture this often-overlooked dimension of biodiversity—and it too shows losses. “This study underscores the urgent need for biodiversity-sensitive land use. A continued decline in insect diversity could have far-reaching consequences for the health and stability of ecosystems.
Biotic communities are vital for providing ecological functions and ecosystem services. As a 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 abundant in all terrestrial ecosystems and display a wide variation among species in almost any aspect of their biology. Because of the large numbers of insects and great intra and inter-specific variety the functional significance of insects is enormous and the ecosystem services provided by insects vital. Insects are the key components in diverse ecosystems as major role players in functioning of ecosystem processes. Since insects are mostly perceived as pests or potential pests, this ecological importance of insects often goes unnoticed. The main ecological functions of insects in ecosystems are ecosystem cycling, pollination, predation/parasitism, and decomposition:
For as long as humans practiced 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. Aside from anthropocentric perception and societal prejudice, insects are not pests in an ecological or evolutionary context. Insects are 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 stabilize 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 includes hundreds of species of solitary bees, bumblebees, flies, beetles and butterflies, and in several crops, wild bee species are more important for pollination than the honeybee, Apis mellifera. Globally pollination services by insects are estimated to contribute 9.5% to yield of crop production.
Pest control is inevitability in agriculture. Predatory insects contribute significant ecosystem functions by controlling pest insects in cultivated crops. It was indicated in 75% of field studies that generalist predators reduce pest populations in arable farmland significantly, with ground beetles being dominant generalist predators in arable crops and effectively reducing population sizes of economically significant agricultural pests such as aphids, slugs, root feeding flies and phytophagous beetles. Insects are also important in improving agricultural soil. Through their activity in the soil, dung beetles increase nitrogen, phosphorous, potassium, calcium and magnesium or total proteins content which significantly elevate the yield of wheat plants relative to chemical fertilizers.
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