The greatest biodiversity loss is expected to occur in invertebrates, specifically insects. Insects represent 75 percent of animals and plant species across the globe. There are approximately 5.5 million insect species, but only 10 percent have been identified so far. Above all, only 5000 insect species cause harm to agricultural plants, farm animals, or human beings.

Insects decline is a key threat to biodiversity loss because insects are directly related to human health. For example, if we completely remove pollinators from our ecosystem, global deaths would increase by 1.4 million annually from non-communicable and malnutritional-related diseases. We get our essential micronutrients (such as vitamins A and C, antioxidants, lycopene, b-tocopherol and folic acid) from insect-pollinated crops, where at least 87 percent of the major food crops directly depend on insects. Therefore, insect decline is an emerging global environmental risk. It is estimated that over 40 percent of insect species are endangered to extinction.

Use of insecticides

Insect-killing chemicals (insecticides) are the key drivers of worldwide insect decline, including other drivers such as loss of habitat and intensification of agriculture lands, fertiliser inputs, introduced species, and climate change. These toxic chemicals cause severely negative impacts on insects’ survival (growth, development, life span, and fertility) and behaviour (choice of food plant, flight directions, a place to lay eggs, etc.)

In the agroecosystem, insects can be categorised into beneficial (good) and non-beneficial (bad or pest) insects. Beneficial insects include pollinators and natural enemies (predators and parasites) of the pest-insects. Economically, services of pollinators have been valued at over $500 billion, while natural enemies of pest-insects have been valued at over $400 billion.

Insecticides generally do not reach the target pest-insects, and significantly affect non-target organisms like beneficial insects, or other organisms. The negative effects of insecticides on pollinating insects such as bees and flies are dramatically high.

Insecticides use in Nepal

Insecticides, especially neonicotinoids, are widely used in Nepal. They are water-soluble, and their prophylactic usage pollutes water and soil that impact the aquatic ecosystem. Not only insects but the decline in various insect-eating birds is also linked to the use of neonicotinoids. Researchers found residues of dichlorodiphenyltrichloroethane (DDT) in the soil samples from Rupandehi and Biratnagar, although DDT has been banned in Nepal since 2001. Unfortunately, Nepal has no proper control over pesticide usage.

Nepali farmers are unaware of pesticide risk. Therefore, educational programmes should be carried out and policies must be implemented for stricter regulations on pesticide use. Furthermore, to reduce the amount of farmland insecticides, government and non-government sectors should conduct integrated pest management (IPM) trainings/workshops by actively involving farmers.

Effects of artificial light

It is also very important to note that artificial light at night directly impacts the day/night cycle of plants and animals. Light pollution is one of the drivers of insect decline—too much artificial light in the wrong place at the wrong time.

Currently, around 25 percent of the Earth's surface is illuminated artificially. Different insect orders have different impacts. Street lights act as vacuum cleaners to the night-flying insects such as moths because they get attracted to the artificial lights, disturbing their typical environment and behavioural patterns. Fireflies, which rely on bioluminescent signals to attract potential mates find it challenging in the places with an excessive amount of light. Another example is mayflies that live and breed only for a day. Light reflecting off a pitch road can confuse them to lay their eggs on the road instead of water surfaces—this single error may eliminate the population overnight. Research suggests using amber-filtered LED bulbs instead of white LED bulbs attract fewer insects.

Protecting the insects

The Himalayan range is a highly vulnerable ecosystem, especially due to climate change and biodiversity loss. Reports suggest that the earth's temperature will be at least 0.3 degrees Celsius higher in the Hindu Kush Himalayan region than the expected global warming of 1.5 degrees Celsius. In the context of Nepal, our biodiversity is largely at risk because of climate change, alien/invasive species, land-use change, pollution, etc. For example, Nepal is one of the top 10 countries with the highest air pollution, and polluted air impacts insect-mediated plant pollination.

It is essential to highlight that insects are the ecosystem service providers running the world. Humanity must save insects as human-insect interaction is intertwined. Apart from food security, insects serve in nutrient cycling, soil formation, decomposition, biological pest control, maintenance of the food web, and many more.

Each of us can participate in the conservation of insects by adopting behaviours and habits, regardless of background and occupation, that mitigate insect declines. For instance, one should plant flowers in the garden or backyard that attract insects or grow native plants and limit the use of artificial exterior lighting. Instead of being afraid, parents and educators should encourage children and students to change their perception of insects as beautiful animals.

Strikingly, Nepal contributes the largest volume of published literature on the realm of ecology, particularly on Himalayan biodiversity. For now, research should be aimed at better understanding the changes in insect abundance and diversity. Nepali researchers and the general public must urgently call for prioritising insect conservation to develop government policies by creating a mini-jungle for insects (and birds) by planting native wildflowers.