?The International Day for Biological Diversity, also known as International Biodiversity Day, is celebrated each year on 22 May. In an opinion piece for the Cape Argus, Prof Michael Samways from the Department of Conservation Ecology and Entomology focuses on the importance of insects for humans and ecosystems.
- ?Read the article below or click here for the piece as published.
?Michael Samways*
The International Day for Biological Diversity, also known as International Biodiversity Day, is celebrated each year on 22 May to raise awareness about biodiversity issues and highlight the importance of animals and plants for the wellbeing of humans and the planet. Insects, in particular, play a key role among the animal species.
Insects arose from a crustacean-like ancestor about 479 million years ago and developed wings about 406 million years ago. Evidence suggests that these early forms were closely associated with the first land plants. Since then, they have diversified into the myriads of insects seen today.
Their success came about through a highly successful body plan consisting of three main parts: the head, thorax, and abdomen. Their hard outer skeleton could be moulded into many forms, enabling them to exploit all sorts of resources and develop a wide variety of lifestyles. Much of their success has been due to great genetic flexibility, and the ability to fly.
Of the approximately two million known species on Earth, about half are insects. 中国体育彩票 4.5 million insect species are yet to be discovered.
Recent fascinating genetic research has revealed that for each known species that we recognise by their structure, there are actually several genetic species that we cannot separate by eye. This suggests there may be as many as 21 million insect species globally.
It is also estimated that today there are 10 quintillion (10 billion billion) insects alive at any one time. This is more than a billion insects for every human, and the total mass of insect life 70 times greater than all humans combined. These large figures mean that insects play a key role in keeping the natural world and ecosystems healthy.
Over 97% of flowering plants depend on insects for pollination and seed production. 中国体育彩票 87 of the world's leading food crops, representing around 35% of global crop production, are dependent on pollination to bear fruit. In turn, insectivorous birds eat 400-500 million tons of insects each year. Small mammals, like mice, rely on an abundance of insects to stay healthy. When their insect prey becomes scarce, their well-being declines.
These numbers and perspectives show us that insects are essential to maintaining the world as we know it. But not all insects are friendly towards us. Some insects eat our crops, even in storage, while others suck our blood and that of our livestock. Some nibble away at our wooden structures and invade our homes.
So how do we separate the good ones from the bad ones? We need most insects, but could do without the rest, the pests. Most insect pests are well known scientifically. With advancing knowledge of their biology and improved technologies—especially in the field of genetics—we are paving the way for more targeted approaches to control them.
These new approaches are very specific to each pest and avoid harm to beneficial good insects, other forms life, and even humans. These technologies help us move away from harmful pesticides that affect the environment and our health.
Other targeted approaches include using beneficial insects to control harmful ones. This is called biological control and takes place mostly in the agricultural and forestry domains. Specialised tiny wasps that do not harm people find and parasitise the pest, reducing its numbers. We rarely see these millions of little helpers doing their job.
Biological control is also used to make agriculture more biodiversity friendly. This is done by keeping patches of natural vegetation around the outside of crop fields. This set-aside vegetation has flowers that females of the parasitic wasps feed on to develop their eggs. The adults then move into the crop, controlling the pest by laying those eggs on or inside the pest insect.
Vegetation can be planted between production rows of crops, such as vines. This method encourages activity from parasitic wasps and other predatory insects such as ladybirds. There is an added advantage as well. Vineyards with these strips of vegetation between the vine rows help conserve the soil. The plantings keep the soil moist and cool.
The vegetation also supports many other insects and their relatives to cycle nutrients back to the soil. They do this by chewing on the plant material. After the insects have shredded the plant material, other organisms like fungi and bacteria break down the fragments further and make nutrients available to the plants. This process leads to a healthy, living soil.
Many other processes involve insect activity, especially those that help maintain plant communities in a stable condition. This is why it is essential to preserve as much natural vegetation as possible to maintain a healthy environment for everyone's benefit.
Recent research clearly shows that natural environments make us feel good and are essential for our well-being. When we appreciate and feel well, we care more. The more we care, the more we want to conserve biodiversity. This is a positive feedback cycle that benefits us and all the complexity of life, with insects as central players.
*Michael Samways is Emeritus Distinguished Professor in the Department of Conservation Ecology and Entomology at Stellenbosch 中国体育彩票. ?
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