You must have heard and are concerned about the rapid fall in number of majestic tigers, sea turtles, adorable giant pandas, elephants, our one of the closest relatives Orangutans, White Rhinos but it not easy to notice the alarming decline in number of insects which can have “catastrophic consequences for both the planet’s ecosystems and for the survival of mankind”.
According to the first global scientific review about insect population published in the journal Biological Conservation, more than 40% of insects species are declining and a third are endangered, reported The Guardian. The planet is at the start of sixth mass extinction(the first one due to human activities), with huge losses already reported in population of larger animals easier to study. But insects are the most abundant animals weighing as much as 17 times the entire humanity and their rate of extinction is eight times faster than that of mammals, birds and reptiles. Their total mass is falling by a “shocking” 2.5% each year. According to Francisco Sanchez-Bayo of University of Sydney, one of the co-authors of the review “It is very rapid. In 10 years you will have a quarter less, in 50 years only half left and in 100 years you will have none”.
Insects are “essential” for the proper functioning of our planet’s ecosystems, as food for creatures such as many birds, reptiles, amphibians, fish and as pollinators and recyclers of nutrients.
In Germany and Puerto Rico, rapid decline in insect population has been reported but the review strongly emphasizes that the crisis not limited to a few countries, it is global. In Puerto Rico, effects of such rapid decline have already been seen where a recent study revealed a 98% fall in ground insects over 35 years and animals dependent on insects for food starved to death.
The review co-authored by Sanchez-Bayo and Kris Wyckhuys at the China Academy of Agricultural Sciences at Beijing selected the 73 best studies to assess the insect population and decline. Most of these studies were done in Western Europe and the US, while a few were also done in Australia, China, Brazil and South Africa, but very few elsewhere.
Butterflies and moths are among the worst hit. The number of widespread butterfly species plummeted by 58% on farmed land in England between 2000 and 2009. The biggest recorded decrease in insect population was noticed in the United Kingdom, although this is probably a result of being more intensely studied than most other countries. Bees have also been affected, number of honeybee colonies in the US have dropped by 3.5 million since 1947. Many species of beetle have also declined especially dung beetles. But there are very big gaps in knowledge, hardly any information is available about many flies, ants, aphids, shield bugs and crickets. And experts say that there is no reason to believe that they are doing any better than the studied species.
A small number of species which can readily adapt to changes are increasing in number, for example, the common Eastern bumblebee in US due to its tolerance of pesticides but it is not anywhere near to outweigh or even match the decline.
Causes of the decline
Pesticides, fertilizers and heavy land use for farming are one of the main reasons for this decline. Sanchez-Bayo said “The main cause of decline is agricultural intensification. That means the elimination of all trees and shrubs that normally surround the fields, so there are plain, bare fields that are treated with synthetic fertilisers and pesticides”. The decline started in the early 20th century but the introduction of New class of pesticides such as neonicotinoids and fipronil in the last 20 years has been particularly harmful as they are used routinely and persist in the environment: “They sterilise the soil, killing all the shrubs”. In tropical areas, where intensive agriculture is not very common, the rising temperatures due to climate change are one of the main reasons for the decline. Species of insects present in tropical areas have adapted to very stable conditions, have very little ability to change and thus even little changes can have cascading effects as seen in Puerto Rico.
Prof Paul Ehrlich of the Stanford University in the US has seen the decline first hand. He studied checkerspot butterflies on Stanford’s Jasper Ridge reserve in 1960 but by 2000 they had all gone mainly because of climate change.
Needless to say, almost every scientist agrees that this decline is a very serious global problem. Prof Dave Goulson of the University of Sussex said “It should be of huge concern to all of us, for insects are at the heart of every food web, they pollinate the large majority of plant species, keep the soul healthy, recycle nutrients, control pests, and much more. Love them or loathe them, we humans cannot survive without insects”.
Timothy Schowalter, Professor of Entomology (branch of zoology concerned with study of insects) at Louisiana State University told Business Insider, “The pollinator declines jeopardize 35% of our global food supply, which is why European countries are mandating protection and restoration of pollinator habitats”.
What can be done to undo or at least mitigate the damage?
According to the review “Unless we change our ways to producing food, insects as a whole will go down the path of extinction in a few decades. The repercussions this will have for the planet’s ecosystems are catastrophic, to say the least”. We must change the way we produce food, Sanchez-Bayo said that organic farms have more insects, hence organic farming must be promoted. The number of pesticides used in agriculture must be reduced as occasional use of pesticides is not that much harmful to the inserts. The authors of the study wrote, “It is imperative that current pesticide usage patterns, mainly insecticides and fungicides, are reduced to a minimum”. In addition to this, insect habitats must be restored.
Buying organic food is the action we can take to curb this global decline, according to leading scientists. We can also urge policymakers to make laws limiting pesticide use on farms. The most critical large-scale action that can be taken is to cut down the enormous public subsidies to insecticides and fertilizers. Although data for India is not available it is well known that the use of insecticides and inorganic fertilizers has increased in India. Thus, incentives must be provided to those farmers doing Organic Farming.
Also Read: For The First Time, World’s Tallest Mammal, Giraffes, Face The Threat Of Extinction