Humanity is heading towards a catastrophe as insect numbers across the world plummet and could be gone in entirety by the next century, according to a new study.
‘Worldwide decline of the entomofauna: A review of its drivers’ has been written by Francisco Sanchez-Bayo at the University of Sydney, Australia, and Kris Wyckhuys at the China Academy of Agricultural Sciences in Beijing. It has been published in the journal, Biological Conservation.
The researchers, who reviewed 73 long-term surveys of insects published in the past 40 years, found that over 40 per cent of insect species could go extinct in the next few decades, with butterflies, bees and dung beetles most affected.
Insects’ rate of extinction is eight times faster than that of mammals, birds and reptiles, says the study. It is 2.5 per cent a year, according to the data available. This, say the researchers, suggests that insects could vanish within a century.
The main causes for the decline, they say, is habitat loss, pollution from pesticides and fertilisers used on farms, as well as emissions from factories and cities, parasites and diseases, and climate change.
“Unless we change our ways of producing food, insects as a whole will go down the path of extinction in a few decades,” write the researchers. “The repercussions this will have for the planet’s ecosystems are catastrophic to say the least.”
That is because insects are the most varied and abundant animals on earth. There are 17 times as many insects as humans. They are essential for the proper functioning of all ecosystems, as food for other creatures, pollinators and recyclers of nutrients.
However, some scientists have raised doubts over the study. Ecologist Georgina Mace of University College London, told the New Scientist while the study had been presented as a global study, almost all of the 73 studies reviewed were done in Europe and the US. There was just one study each from Brazil and South Africa for the continents of South America and Africa.
“So for huge parts of the planet, we simply do not know how insects are faring,” she remarked.