Very little is known about 99% of all insects on Earth

Insects quietly run the world. They pollinate crops, recycle organic matter, and feed countless animals. Despite their importance, scientists know very little about how most insect species are doing.

There are about one million known insect species. Yet only 1% – roughly 12,100 species – have been assessed by the International Union for Conservation of Nature (IUCN). Among these, around 20% face threats of extinction.

Monitoring efforts have mostly focused on butterflies, dragonflies, and bumblebees in North America and Europe. Other regions, especially Africa, Asia, and South America, remain largely unstudied. The global picture of insect health is still blurry.

Urgent plan to track insect declines

To address this, scientists from the UK Centre for Ecology & Hydrology (UKCEH) and the Zoological Society of London (ZSL) propose a broader method. Their goal is to act quickly before climate change, pollution, land use shifts, and invasive species cause irreversible harm.

The new method integrates several ways of studying insects. It includes long-term tracking of diversity and abundance, comparisons across different habitats, structured expert input, and controlled experiments. The researchers believe this mix offers a more complete view than any single approach.

Dr. Rob Cooke is an ecological modeler at UKCEH and joint lead author of the study.

“We need to find out whether insect declines are widespread and what’s causing them. The challenge is like a giant jigsaw puzzle where there are thousands of missing pieces, but we do not have decades to wait to fill these gaps and then act,“ noted Dr. Cook.

“There is a lot of interest in monitoring charismatic species such as bees and butterflies, but few people care about the supposedly unpleasant insects, even though they too provide benefits for us.”

“For example, earwigs feed on aphids and other garden pests while cockroaches eat decaying material and keep soils healthy.”

An insect monitoring system that works

The framework combines time series trends, such as counting how butterfly populations shift over a decade. It also uses spatial comparisons to see how insects vary between forests, grasslands, or farms.

Researchers conduct experiments that test insect responses to threats, like removing pesticides or invasive species from certain areas. When hard data is missing, they gather expert judgments to predict how insects may react to different pressures.

This layered approach lets scientists make more informed decisions while still being open about gaps and uncertainties. It balances speed and precision in a way that single-method studies cannot match.

Case for insect inclusion

“Insects are an incredibly important part of our ecosystems, pollinating around 80% of flowering plant species and vital for 35% of global food production, yet they are undervalued and understudied,“ noted Dr. Charlotte Outhwaite of ZSL’s Institute of Zoology, joint lead author of the study.

“With a million described species it would take too long to figure what works best for each species. Instead we want to find large-scale actions that benefit the most insects. For this, we need to use all the available information we have.”

To meet this goal, the scientists propose using known responses from well-studied insects to estimate how lesser-known species might respond under similar conditions. This gives policymakers a usable way forward, even if some data is still missing.

Next phase of the GLiTRS project

The new framework will now guide the Global Insect Threat-Response Synthesis (GLiTRS) project. Researchers aim to model insect responses to major threats across many environments.

By combining all sources of data – field studies, expert insights, and experiments – they hope to build a reliable picture of insect health worldwide. This new framework doesn’t pretend to be perfect.

But it offers something we desperately need: a way to understand insect declines in real time, using every piece of information available. It also shows how science can adapt when faced with complex, global challenges.

Insects have been quietly supporting life on Earth for hundreds of millions of years. Now they need our attention. The question is not whether we care, but whether we will act before it’s too late.

The project is backed by the Natural Environment Research Council (NERC). It involves teams from the Natural History Museum, University College London, the University of Cambridge, and Imperial College London.

The study is published in the journal Science.

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