When did you last see a ladybird? A red admiral butterfly? An orange-tailed mining bee? So far in 2024 I have personally seen just one ladybird. The chances are that you’ve seen very few this year, if any. While insect populations are notoriously changeable because of weather conditions, to the untrained eye, the absence of flying and crawling insects is palpable.
Even wasps appear to be scarce these days, compared with my childhood where they were a proper menace every August. Flying insects of all kinds used to be abundant, a cloud of nuisance over your head as you walked in the countryside and their tiny bodies splashed across windscreens on any car journey. Fields used to be full of beetles, earwigs and blowflies scavenging on cow dung.
And here’s the thing: perception of insect populations is heavily influenced by what is known as “shifting baseline syndrome”, which means that if you were never used to seeing healthy populations of any given species, you don’t notice when they go into decline or disappear altogether. Within my own lifetime, half of our vertebrate wildlife has been lost. That does not bode well for insects – the very foundation of the food chain.
Traditionally, entomologists focused on identifying species of insects and observing their life cycles and their fascinating habits (check out the Bombardier Beetle or the Orchid Bee for example). It is only in recent decades that the proper study of insect populations – their distribution and abundance – began in earnest and even today, much of the data is captured by volunteers who literally count insects as they spot them, or by the weight in biomass of insects trapped in nets. In Ireland, this work is co-ordinated by the National Biodiversity Data Centre and a team of citizen scientists that monitor insect populations.
Insect decline is, unfortunately, a very real phenomenon. In 2017, scientists studying the Krefeld nature reserves in Germany found a drop of 75 per cent between 1989 and 2016. Catastrophic declines have since been reported around the world in both developed and developing countries, and for both species and populations.
According to a 2019 review by Prof David Wagner in the Annual Review of Entomology, declines of abundant species can be especially worrisome, given that they anchor trophic interactions and shoulder many of the essential ecosystem services of their respective communities. Grasslands seem to be faring the worst, with losses on average of two-thirds of their insect populations, according to Dave Goulson, the author of Silent Earth.
What is driving these observed collapses? And what does it all mean for us? In addition to widely recognised threats to insect biodiversity, eg, habitat destruction, agricultural intensification (including pesticide use), climate change and invasive species, insects are also vulnerable to the effects of burning fossil fuels, droughts and changes in precipitation patterns.
Man-made toxins in pesticides, insecticides and fungicides have been applied to kill insect pests and even when these are advertised as “targeted” they have a deadly impact on pollinators. Dave Goulson estimates that the pesticides applied on UK farmland alone are sufficient to kill the planet’s three trillion honeybees several times over.
For purely self-interested reasons, we should care about insects. They provide essential ecosystem functions in food webs (both as predators and prey), species interactions (pollination), and nutrient cycling (decomposing). They are intimately involved in all terrestrial and freshwater food chains and food webs. If you like salmon or hedgehogs, or frogs or sparrowhawks, you should like insects.
Without pollinators it would be impossible to produce anything like the “five a day” fruit and vegetables we are all recommended to eat. Of course, while there is an ethical argument that says whether or not an insect is useful to us, the fact that it exists at all is reason enough to let it be. Who are we to play God after all, and decide what gets to live and what should be let go extinct.
Despite the gloomy statistics, all is not lost. Irish experts have drawn up a national pollinator plan for everyone to enhance wildlife and promote ideal conditions for pollinators to thrive. According to Dr Tomás Murray of the NBDC, we need to protect and expand existing areas that support large and diverse insect communities, restore ones we’ve damaged and link them all up so insects can move freely across the landscape.
Just like the Pollinator Plan, this concept of creating space for insects can be applied at garden, farm, landscape, county or national scales alongside ending the use of harmful chemicals. In the past few years, many Biodiversity Officers have been appointed in county councils around the country to work alongside local nature groups to promote and support the pollinator plan. There is so much to do, and not much time left to do it.
Sadhbh O’Neill is an independent climate and environmental researcher
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