The most alarming thing is that we don’t know why the populations are declining. It may be due to urbanisation, insecticide use, elimination of plants that form insect habitats and food, etc. Climate change and the rising sea level may also have something to do with it.
Whatever the cause, we need to ensure we protect insect populations because they play a vital role in the environment.
For instance, insects pollinate flowers and produce. Without insects, the human population won’t be able to consume plenty of fresh fruits, vegetables, and honey. In addition, manufacturing industries won’t be able to produce many silk and beeswax products in the absence of insects.
Insects also play a vital role as decomposers: they break down carcasses and various waste products. If no insects existed, various contaminants and impurities would proliferate significantly.
Experts consider some insects beneficial because they prey on certain pest species which may harm crops and other forms of livelihood. For example, the praying mantis feeds on beetles, caterpillars, and aphids (which are known to destroy crops such as wheat, barley, and oats).
Finally, insects play an important role in the food web: various reptiles, amphibians, and birds consume them. Even some farmers are encouraging people to consume insect protein because of their impressive nutritional profiles.
By having custom insect screens installed around the home, we can safely keep them outdoors instead of using nasty insect sprays or traps to kill the already declining insect population.
Source: http://www.abc.net.au/news/2018-02-24/decline-in-insect-population-baffles-scientists/9481136