It is spring, the sky smells, insects fly and forage. Vital base for biodiversity, they are nonetheless unloved and endangered. Author of “Animals in the Gospel” (SFPC) and experienced butterfly hunter, Tugdual Derville sees in these six-legged creatures an inexhaustible source of wonder, though we have to worry about the collapse of their populations. .
“Go away! Miserable insect, excrement from the ground. If there’s a point where most urban and rural people still agree with La Fontaine’s lion, scornful insult of the mosquito that annoys him, it’s the status of ‘little beast’ in common, and insects in particular, usually confused. Few can tell the difference between insects (their six legs and bare mouth parts) and other arthropods (shovels, millipedes, spiders, ticks, scorpions, etc.). All are objects of ignorance and generally of aversion. The latter know the extent to which they constitute the vital base of biodiversity, both animals and plants. Just one example: 80% of wild plants depend on it for pollination.
Between thirty and three million species… are to be discovered
Nature’s paradox: on the one hand, insects are the most deadly animals through the transmission of diseases; just as the medieval plague wiped out up to 50% of the european population, due to the flea vector, malaria still kills about 800,000 people every year in tropical countries via certain species of mosquitoes … But on the other hand life on earth would be threatened if this base of the food chain disappeared. One million species of insects have already been described. They alone represent 70% of the animals’ biodiversity. It would be left to discover between three and thirty million! The margin of uncertainty tells the mystery. Promise of more discoveries and an inexhaustible source of wonder.
Most experts are concerned and estimate a 80% drop in their numbers [des insectes] in Europe in three decades.
The collapse of their populations should affect all of humanity. But how do you measure the damage? Entomologists agree to lament the lack of sufficient long-term data, while lamenting the obvious: after every spring trip, our windshields are almost no longer obsessed with insect waste, trapped in speed. In a few decades, butterflies, day and night, have become discreet. Everyone has – thanks to beekeepers – heard about the controversies surrounding the excess mortality of honey bees, the tip of the iceberg, because the population of wild bees – and in particular about the terrestrial bumble bee (Bombus terrestris) – even more crucial for pollination, is catastrophic. These are the reduction and impoverishment of the ecosystems needed for their life cycle, artificialization of the soil, night lighting, climatic upheavals and decades of massive proliferation of increasingly powerful insecticides. What does the general public think? And what can he do?
Admittedly, participatory observation campaigns are regularly encouraged. More symbolic than effective, they have the benefit of encouraging the recipients of a garden – or even a simple balcony – to finally look closely at their small inhabitants or visitors without reserving their admiration for exotic insects. The latter, which is known to be more beautiful, is above all – in the tropics – larger. But we come across – all over France, even in urban areas – specimens with shiny decoration. example? The magnificent cedar bupresto (Lamprodila festival), which its small size (1 cm) makes discreet. When we look on the internet for information about this beetle, our ambivalence about insects is obvious: “The cedar beetle: how to get rid of it?” Titles an article from the website of World, in its garden department – because it is a “pest” of the monotonous plant walls that invade residential areas. On the contrary, the scientific sites emphasize that “the insect is protected in many regions, including the Ile-de-France”! Incompatible appearance. However, it should be understood that farmers – even more than gardeners – are reluctant to see their crops being destroyed by insects.
Against the background of an undeniable biodiversity crisis, a controversy has been raging against entomologists (insect specialists) for several years with conflicting articles published in prestigious scientific journals. Most experts are concerned and estimate the decline in their numbers in Europe to 80% in three decades. Some go so far as to wave the exaggerated threat of total extinction: “Insects can disappear from the planet within 100 years”, was an article in World in February 2019. But some naturalists thought they could put the alarm in perspective. In an article by Science dated April 2020, a group of authors suggested that the observed decline was not as dizzying as claimed. This reversal is based on an extensive collection of studies: Terrestrial insects would have fallen by only 9% per year. decade, and the number of aquatic insects would even have increased by 11% per. decade! This “calming” meta-study immediately generated strong protests and setbacks: other naturalists consider its data questionable, even absurd, both heterogeneous and biased.
Gift of neonicotinoids
Like the climate debate, it is not just the scale of the entomological catastrophe that is being discussed; its causes are also hotly debated. At this point, world-renowned biodiversity defense movements have been accused of conflicts of interest for accepting funding from agri-food producers. They are suspected by their opponents either to relativize or to silence the “chemical” cause of the collapse of the insects, that is, the “neonicotinoids”, these (also?) Effective pesticides. To achieve their goals, these companies would use the smoke blur technique. By investing massively in the search for other causes of insect decline, they try to focus the communication of nature’s defenders on these derivatives, to make people forget the proven “poison” that neonicotinoids constitute. This is how the tobacco industry has long acted when it funded research into “causes” of cancer other than smoking.
How to understand the value of insects? The fascinating birds (many of which depend on their small prey) are defended spontaneously, for in every human being sleeps an ornithologist who is quick to marvel. But the animals are too small to be popular and too invasive – and some aggressive species – not to provoke rejection. Their defenders are saddened by their lack of weight in the public debate. Nature lovers take comfort in leaving insects, in the spaces placed under their responsibility, carefully unprotected areas where weeds and piles of rotting wood give them shelter and shelter. Little consolation, for it is together that we must take up the challenge. Insects are only one key piece – albeit largely hidden – in the complex puzzle of biodiversity, if all pieces are to stick together.