The decline of insect populations and the role of conservation globally

Abstract

Insect populations worldwide are experiencing alarming declines due to habitat

destruction, pesticide use and climate change. While bees are commonly cited as

primary pollinators, recent research highlights that beetles play a more significant

role in pollination, particularly in Australia. Studies indicate that insect populations

have declined by up to 75% over the past few decades, with profound consequences

for global biodiversity and ecosystems (Hallmann et al., 2017; Gaume & Desquilbet,

2024).

This article examines the factors contributing to insect decline, the ecological importance of insects—especially beetles in pollination—and practical conservation strategies that individuals and families can implement. Drawing from recent studies from the Museum of Victoria, CSIRO and conservation biology research, this piece provides a comprehensive guide to protecting insect biodiversity.

Introduction

Insects form the foundation of ecosystems, contributing to pollination, decomposition and food web dynamics. However, global insect populations are declining at unprecedented rates, with some studies estimating up to 75% reduction in insect species (Hallmann et al., 2017; Gaume & Desquilbet, 2024). In Australia, habitat loss, climate change and pesticide use have significantly impacted native insect populations (Samways et al., 2020). This decline threatens insect biodiversity and their ecosystems and agricultural systems that rely on them performing key tasks (e.g. beetles have a key task of pollinating plants).

The role of insects in ecosystems

Pollination: More than just bees

Although bees are widely recognised as crucial pollinators, the Museum of Victoria's research shows that beetles dominate many ecosystems (Museum Victoria, 2023). Beetle pollination, or cantharophily, is considered one of the oldest forms of pollination. Many Australian plant species, including native flowering trees and shrubs, rely on beetles for pollination.

Unlike bees, which collect nectar and pollen efficiently, beetles often feed on pollen as a food source and then transfer it as they move between flowers. Plants such as tea trees (Leptospermum species) and some native lilies depend on beetles for pollination (Museum Victoria, 2023). Recognising the role of beetles broadens our understanding of pollination and highlights the need for diverse insect conservation strategies.

Other roles of insects

·         Decomposition. Many insects, such as dung beetles and termites, break down organic matter, recycling nutrients back into the soil (Halcroft et al., 2013).

·         Pest Control. Predatory insects, including ladybirds and lacewings, help regulate pest populations naturally (Goulson, Nicholls, Botías, & Rotheray, 2015).

·         Food Source. Insects are a critical food source for birds, reptiles and mammals, supporting broader biodiversity (Samways et al., 2020).

Drivers of insect decline

A growing body of research identifies multiple interacting factors behind the widespread decline in insect populations. Some of the most significant include:

1.      Habitat loss and fragmentation. Urban expansion and agricultural intensification have dramatically reduced the availability of suitable insect habitats (Goulson et al., 2015; Grevé et al., 2024).

2.      Pesticide use. Chemical pesticides, including neonicotinoids, are directly linked to insect population declines (Forister et al., 2019).

3.      Climate change. Changes in temperature and rain patterns disrupt insect lifecycles and migration routes (Samways et al., 2020).

4.      Land-use changes. The shift toward bioenergy and monoculture agriculture reduces floral diversity and insect nesting habitats (Grevé et al., 2024).

5.      Light pollution. Artificial lights interfere with nocturnal insect behaviours, disrupting feeding and mating patterns (Owens & Lewis, 2018).

Conservation strategies for individuals and families

While large-scale conservation efforts are necessary, individuals and families can take these steps to preserve essential insect species:

1. Create insect-friendly gardens

·         Plant native flora. Incorporate diverse native flowering plants to support various insects (Haaland, Naisbit, & Bersier, 2011).

·         Provide year-round blooming plants. Ensure a continuous nectar supply for pollinators (Tallamy, 2013).

·         Reduce lawn areas. Replace grass with wildflower gardens and native shrubs to create habitats.

2. Provide shelter and nesting sites

·         Install insect hotels. Wooden bee hotels, rock piles and bark shelters offer nesting spaces for solitary bees, beetles, and other insects (University of Melbourne, 2022).

·         Leave leaf Litter and logs. Many insects rely on natural debris for shelter and breeding sites.

3. Reduce chemical use

·         Avoid pesticides and herbicides. Use organic gardening practices to minimise harm to beneficial insects (Goulson et al., 2015).

·         Encourage natural pest control. Introduce predator-friendly plants that attract ladybirds and lacewings.

4. Support Biodiversity Beyond Gardens

·         Create microhabitats. Retain fallen logs, compost heaps and small water sources to support diverse insect life.

·         Participate in citizen science: Programs like Wild Pollinator Count and iNaturalist help track insect populations and provide valuable data for conservation research (Samways et al., 2020).

5. Reduce light pollution

·         Use warm-coloured outdoor lighting. Cooler lights attract fewer insects, reducing disruptions to nocturnal species (Owens & Lewis, 2018).

·         Turn off unnecessary outdoor lights. This simple step can help preserve the natural behaviours of nocturnal insects.

 Conclusion

The decline of insect populations poses a significant threat to global biodiversity and

ecosystem stability. While habitat loss, climate change, and pesticide use continue to

contribute to insect decline, conservation efforts at individual and community levels

can make a meaningful difference. Recognising the vital role of beetles as pollinators

and expanding conservation efforts beyond bee-centric approaches ensures a more

holistic approach to insect protection. By taking practical actions, such as creating

insect-friendly gardens, reducing chemical use, and participating in citizen science,

individuals and families can contribute to the preservation of essential insect species.

References

Forister, M. L., Pelton, E. M., & Black, S. H. (2019). Declines in insect abundance

and diversity: We know enough to act now. Conservation Science and Practice, 1(8),

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Gaume, L., & Desquilbet, M. (2024). InsectChange: Comment. Peer Community

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Goulson, D., Nicholls, E., Botías, C., & Rotheray, E. L. (2015). Bee declines driven

by combined stress from parasites, pesticides, and lack of flowers. Science,

347(6229), 1255957. https://doi.org/10.1126/science.1255957

Hallmann, C. A., et al. (2017). More than 75 percent decline over 27 years in total

flying insect biomass in protected areas. PLOS ONE, 12(10), e0185809.

Museum Victoria. (2023). The role of beetles in pollination. Museum Victoria

Research Reports. Retrieved from https://museumsvictoria.com.au

Samways, M. J., et al. (2020). Solutions for humanity on how to conserve insects.

Biological Conservation, 242, 108427.