Without our being aware of it, insects and other arthropods regulate our environment on a daily basis. Some visit flowers for nectar or pollen, while others nibble away at tall grass. Flies are gobbled up by birds, and maggots devour organic matter. In the soil, ants dig tunnels and turn over the earth. In lake and river bottoms, a large number of them filter the water and serve as food for fish. All that, and with no one catching a glimpse – or barely! Nevertheless, if those little animals were to disappear overnight, the stability of our ecosystems would be affected and our day-to-day lives deeply disrupted. We’re not there yet, but…
Researchers are sounding the alarm!
For a while now, scientific studies have been indicating that insect populations are failing. In 2017, European experts who had spent 27 years studying quantities of flying insects calculated a decline of 76 percent in those arthropods in protected natural areas in Germany. A more recent study, conducted in the rainforests of Puerto Rico over a period of 36 years, also reveals drops in biomasses, including decreases of 98 percent and 78 percent for arthropods living on the forest floor and in the canopy. That study moreover demonstrated a parallel drop-off in the numbers of birds, frogs and lizards in the same areas owing to that shortage of food. Among aquatic insects, the population declines would seem to be every bit as important, despite the absence of available knowledge. Accordingly there’s an urgent need to act, because these studies tell us that the changes in the composition of insect communities are warning signs of what is now considered to be the sixth mass extinction to take place on the planet in the last 500 million years.
What are the causes?
We haven’t yet fully grasped the causes behind this collapse. Nevertheless, it’s certain that there are more than one (alteration of natural habitats, pollution of the environment, pesticide use, global warming...) and that they act differently depending on the environments surveyed and on distinctive regional features. And yet, despite that uncertainty, scientists agree in saying that a combination of factors is leading to a generalized deterioration in the living conditions of insects and that the survival of their populations is today gravely threatened.
How do things stand in Québec?
In the Québec region, a lack of long-term data prevents entomologists from comparing and documenting the current state of insect populations. Regardless, we know already that the populations of pollinating insects are declining and that some of them, like the rusty-patched bumblebee (Bombus affinis) and the yellow-banded bumblebee (Bombus terricola), are considered extinct or threatened.
What can we do?
Our own wellbeing is very much involved when it comes to saving the insects. Such a drastic change can’t be ignored, and should be encouraging all of us to take decisive steps in order to avoid the worst. To do so, we must first take a fresh look at these little animals. We must learn to know them better so that we become aware of their essential ecological roles and the benefits we derive from those.