Insects need our help in a warming world

By Netherlands Institute of Ecology

Netherlands Institute of Ecology – “If no action is taken to better understand and reduce the impact of climate change on insects, we will drastically limit our chances of a sustainable future with healthy ecosystems.” That warning in a very topical paper in Ecological Monographs came from 70 scientists from 19 countries around the world. The scientists also provided ways to help insects in a warming world complete with management strategies.

While we’ve heard about insect decline before, we haven’t done much to stop it on a worldwide scale. Climate change is at the top of the world’s to-do list. Something that coincides very well with the COP27 climate change conference in Egypt from Nov. 6 to 18.

Gradual change plus extremes

“Climate change aggravates other human-mediated environmental problems,” said Jeffrey Harvey from the Netherlands Institute of Ecology (NIOO-KNAW) and Vrije Universiteit Amsterdam. “Including habitat loss and fragmentation, various forms of pollution, overharvesting and invasive species.”

Harvey led the major paper by an international team of scientists and together they provided a convincing overview of the role of climate change and climatic extremes in driving insect decline.

The paper is part of the Scientists’ Warning series. “Insects play critical roles in so many ecosystems, but we are rapidly losing at least part of them,” Harvey stressed the urgency. And this seems the case especially in temperate regions. The authors emphasise that both longer-term events and short-term extremes are harming insects in several ways.

“The gradual increase in global surface temperature impacts insects in their physiology, behaviour, phenology, distribution and species interactions.” Harvey added. “But also, more and longer lasting extreme events leave their traces,” such as hot and cold spells, fires, droughts, floods.

Piling up

Evidence of the effects has continued to pile up, and it’s all presented in this review. For instance, fruit flies, butterflies and flour beetles can survive heat waves, but males or females become sterilised and thus unable to reproduce. They become ‘living dead’. Bumblebees in particular prove very sensitive to heat, and climate change is now considered the main factor in the decline of several North American species.

“Cold-blooded insects are among the groups of organisms most seriously affected by climate change, because their body temperature and metabolism are strongly linked with the temperature of the surrounding air,” said Harvey.

One major concern with insect decline in a warming world is that plants – on which insects depend for food and shelter – are similarly affected by climate change. And as insect numbers dwindle, it in turn works its way higher up the food chain. This has happened to many birds, for instance, over the past decades.

Supporting the global economy

Think pollination, pest control, nutrient cycling, and decomposition of waste. Insects represent the overwhelming bulk of biodiversity, and perform vitally important services that sustain human civilization, all worth billions of dollars annually to the global economy.

“The late renowned ant ecologist Edward O. Wilson once argued that ‘it is the little things that run the world.’ And they do!” stated Harvey.

“Over time, insects must adjust their seasonal life-cycles and distributions as the world warms. However, their ability to do this is hindered by other human-caused threats such as habitat destruction and fragmentation, and pesticides,” he continued.

Furthermore, heatwaves and droughts can drastically harm insect populations in the short term, making insects less able to adapt to more gradual warming.

What to do

Importantly, individual people can help by caring for lots of different wild plants, providing food and areas where insects can shelter to ride out climate extremes. And by reducing the use of pesticides and other chemicals.

“Rewilding programs also need to consider micro-scale ecosystems which focus on the conservation of small animals like insects,” Harvey said.

“Insects are tough little critters, and we should be relieved that there is still room to correct our mistakes. We really need to enact policies to stabilize the global climate. In the meantime, at both government and individual levels, we can all pitch in and make urban and rural landscapes more insect-friendly,” he continued.