The scientific paper was published last week in Ecological Monographics and was led by ecologist Jeffrey Harvey of VU Amsterdam and the Netherlands Institute of Ecology (NIOO-KNAW). VU ecologists Jacintha Ellers and Matty Berg are also involved in this study.
A crucial role in ecosystems
Insects are highly important in keeping our ecosystems healthy and running. This is because they provide pollination, are used as pest control, they break down waste and provide new nutrients. These services are crucial for human society. In addition, they provide biodiversity. If the number of insects decreases, you will eventually see that reflected higher up the food chain. You can already notice this in all kinds of bird species over the past decades, where insects are used as food. Harvey: ‘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.’
The gradual increase in global surface temperature impacts insects in their physiology, behaviour, phenology, distribution and species interactions. Also extreme weather events, such as heat waves and floods, lead to problems. For instance, fruit flies, butterflies and flour beetles can survive heat waves, but they become sterilised and thus unable to reproduce. 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,’ says Harvey.
Adaptability is hindered
‘Over time, insects must adjust their seasonal life-cycles and distributions as the world warms,’ says Harvey. ‘However, their ability to do this is hindered by other human-caused threats such as habitat destruction and fragmentation, and pesticides.’ 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.
Solutions and management strategies
In the paper, the scientists discuss a range of solutions and management strategies that may help to buffer insects against climate warming. 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. Reducing the use of pesticides and other chemicals also makes a big difference. Harvey: ‘At the larger scale, we need to address climate change. We really need to enact policies to stabilise 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. Insects are tough little critters and we should be relieved that there is still room to correct our mistakes.’