The Role of Insects in Sustainable Agriculture: A Complete Guide

Harnessing the Power of “Insignificant” Bugs for Sustainable Agriculture – A Comprehensive Guide

Composed and edited by Dr. Nagraani Mahaajan, Publication Director, Advanced Training in Plant Breeding, Maharashtra, India

Fig. 1.: An important pollinator: solitary native digger bee Amegilla violacea, foraging on Calotropis, Photo credit: Dr Amala U, ICAR-NBAIR, Bangalore 

Insects: The Unsung Heroes of Our Ecosystem

Insects, often overlooked, play a critical and underappreciated role in sustaining life on Earth. With over 1 million identified species and an estimated population of 10 quintillion individuals, insects have existed for 400 million years, contributing significantly to biodiversity and ecosystem health. Inspired by Dr. Edward O. Wilson, known as the father of biodiversity, this article explores insects’ essential roles in our ecosystems.

Fig. 2: Relative sizes of the representative organism of each group relate to number of species in that group (Source Link: CHAPTER 9 BIODIVERSITY NATURE’S MEDICINE CABINET )

Dr. Edward O. Wilson’s 1987 paper: “The Little Things that Run the World..” emphasizes the vital role of invertebrates, especially insects, in maintaining Earth’s balance. Invertebrates comprise the majority of biodiversity, with beetles alone accounting for around 290,000 of the nearly 990,000 identified species (fig. 2). Insects provide essential ecosystem services for the survival of many life forms, including humans.

The Importance of Insects in Agriculture and Beyond

Insects are vital for agriculture and ecosystem health, providing numerous benefits to farmers and the environment:

1. Pollination: Bees, butterflies, and beetles are essential for pollination, boosting crop yields and improving fruit quality. About 35% of global food production relies on insect pollination, making them crucial for food security.
2. Pest Control: Beneficial insects like ladybugs and predatory wasps help control pests naturally, reducing the need for chemical pesticides, which leads to healthier crops and lower costs. Some of the beneficial insects are reared in insectaries and released into the field for pest management.
3. Soil Health: Insects like dung beetles break down organic matter, aerating the soil and promoting nutrient cycling, thus essential for sustainable farming.

Ecosystem Services Provided by Insects

Insects contribute to various ecosystem services:

• Provisioning: A service wherein insects provide food and other resources to other living organisms. Insects provide resources such as honey, and in some regions, they are consumed as food, offering a sustainable protein source.
• Regulating: A service that regulates the environment. Insects help control pest populations, reducing the need for harmful pesticides and regulate food web stability (Fig. 3 & Fig. 4).

Fig. 3: A parasitoid Telenomus remus parasitizing Tobacco caterpillar Spodoptera litura eggs

Fig. 4: An anthocorid bug predating on a Mealybug

• Supporting: Service that contributes to pollination, seed dispersal, decomposition, and soil formation. Dung beetles and termites aid in decomposition and nutrient recycling, while pollinators ensure the reproduction of most flowering plants, supporting biodiversity and increasing yield.
• Cultural: Insects add cultural and aesthetic value, from the role of butterflies in inspiring art to the role of some insects in mythology and as religious symbols.

Are We Losing These Bugs? – Are The Insects Disappearing?

Fig. 5: The rate of insect extinction is eight times faster than that of mammals, birds, and reptiles. Photograph: Courtesy of Entomologisher Verein Krefeld. (Source: https://www.theguardian.com/environment/2019/feb/10/plummeting-insect-numbers-threaten-collapse-of-nature)

Despite their crucial contributions, insects are increasingly threatened by habitat degradation, pollution, pesticide overuse, and climate change. This alarming decline, especially in areas of intensive agriculture, raises concerns about the sustainability of the ecosystem services they provide. The extinction of insects could lead to the collapse of many ecosystems reliant on them for pollination, pest control, and decomposition.

Innovative Strategies for Insect Conservation

Farmers can adopt various strategies to encourage beneficial insect populations on their farms:

• Trap Nests for Beneficial Insects

Fig. 6: Trap nests to attract and conserve megachilid bees, which are efficient pollinators (Source: Dr Amala U, ICAR-NBAIR, Bangalore)

Creating trap nests can provide habitats for solitary bees and predatory wasps. These nests attract pollinators and provide homes for natural pest control agents, too, thus increasing crop yields and reducing pest damage (Fig. 6).

• The Push-Pull Strategy

Developed by the International Centre of Insect Physiology and Ecology (ICIPE), this strategy effectively manages pests like the Fall Armyworm in maize crops. Surrounding maize fields with Brachiaria grass attracts pests, while planting Desmodium between maize rows repels pests and attracts their natural enemies. This approach reduces pest infestation on the main crop and enhances yields while maintaining ecological balance.

Collaborative Efforts in Insect Conservation and Community Engagement

Farmers can benefit from participating in community science initiatives that promote insect conservation:

1. Painted Lady Butterflies in California: Community efforts have identified nectaring plants that support pollinators, such as the painted lady butterfly. Planting these nectaring plants can create pollinator-friendly environments, enhancing crop pollination and biodiversity.
2. Urban Pollinator Gardens: Inspired by projects in cities like Melbourne, farmers can create urban gardens that attract insects, support pollinators, and educate local communities about insect conservation.
3. India’s Nature Beetle Mania: Events like “Nature Beetle Mania” engage nature enthusiasts and students in monitoring beetle populations. Observing and identifying beetles can help farmers learn about beneficial species and how to support them.

Successful Restoration and Conservation Efforts

1. Large Blue Butterfly Recovery: The reintroduction of the Large Blue Butterfly in Europe highlights the potential for insect conservation initiatives. Restoring habitats fosters diverse ecosystems that benefit both wildlife and agricultural productivity.
2. Community-Funded Wildflower Corridors: In Sussex, community projects have established wildflower corridors to support pollinators. Farmers can create similar corridors, providing essential habitats for beneficial insects and enhancing crop pollination.

Advocacy for Insect Conservation

Organizations like the Centre for Biological Diversity in the USA advocate for insect conservation through policies that limit pesticide use and promote sustainable farming practices. Farmers can support such policies, enhancing agricultural sustainability and creating a broader impact.

The Role of Scientists in Insect Conservation

Scientists can significantly contribute to the general understanding of insect ecosystems and their interactions with agricultural practices by:

1. Contributing to Policy Development: Informing policymakers about the ecological importance of insects.
2. Innovating Sustainable Practices: Researching and developing integrated pest management modules to support agroecology.
3. Educating the Public: Raising awareness about the roles of insects through outreach programs.
4. Collaborating with Farmers: Applying research findings to on-farm practical conservation strategies.
5. Monitoring Ecosystem Health: Tracking insect populations and ecosystem health to guide conservation efforts.

Take Home Messages for Farmers

1. Insects as Allies: You are advised to protect and use insects for pollination, pest control, maintaining soil health, and thus boosting crop yields.
2. Integrated Pest Management: You can focus on utilizing and preserving beneficial insects to reduce chemical pesticide use.
3. Conservation Strategies: You should implement innovative habitat manipulation methods like the push-pull strategy and encourage growth of non – crop pollinator friendly crops and create pollinator gardens.
4. Community Engagement: Participation in local citizen science initiatives is beneficial.
5. Support Policies: You must advocate for sustainable practices and policies that protect beneficial insects and conserve insect diversity.

References

1. Ballal, C. R. et al. (2021) Chapter : 5: Biological Control for Fall Armyworm Management in Asia, Case study: India, pp. 114-130 In: M. Prasanna, Joseph E. Huesing, Virginia M. Peschke, Regina Eddy (eds). Fall Armyworm in Asia: A Guide for Integrated Pest Management. Mexico, CDMX: CIMMYT.
2. Ballal, C. R. (2022). Success stories in biological control: Lessons learnt.  Vantage: Journal of Thematic Analysis, 3(1): 7-20. ISSN: 2582-7391, DOI: 10.52253/vjta.2022.v03i01.02.
3. Ballal, C. R. and Amala, U. (2022). “Accounting for” and “saving” the ecosystem services provided by insects. pp. 61-77 In: Biodiversity, Ecosystem Services and Climate change (Eds: O.K. Remadevi, K.H. Vinaya Kumar, R.K. Singh) ISBN: 978-93-91355-55-9, EMPRI, Bangalore, 200pp.
4. Ballal, C.R., Sreedevi, K., Salini, S., Gupta, A., Amala, U., Varshney, R. (2022). Biodiversity of Agriculturally Important Insects: Status, Issues, and Challenges. In: Kaur, S., Batish, D., Singh, H., Kohli, R. (eds) Biodiversity in India: Status, Issues and Challenges. Springer, Singapore, https://doi.org/10.1007/978-981-16-9777-7_12
5. Ballal, C. R. and Verghese, A. (2015) Role of parasitoids and predators in the management of insect pests. pp. 307-326, Chapter 29 -In New Horizons in Insect Science: Towards Sustainable Pest Management, K. Chakravarthy (ed.) DOI 10.1007/978-81-322-2089-3_28, © Springer India.
6. Wilson, E. O. (1987) The little things that run the world (The importance and conservation of invertebrates). Conservation Biology 1(4): 344-346.

Further reading

Important Beneficial Insects as Natural Enemies of Crop Pests

Natural Pollination in greenhouse crops using bumblebees and other beneficial insects

Integrated Pest & Disease Management in Greenhouses: A Comprehensive Guide

The Push-Pull Strategy: Controlling Stemborers and Striga to Increase Corn Yields