The World’s Decline in Beneficial Insects and Increase in Pests

Humans have had a large impact on the world’s flora and fauna, and continue to do so every day. We kill things with pesticides and herbicides. We pollute the air and water with the use of fossil fuels and other chemicals. And we have caused climate change, bringing hotter summers, greater fluctuation in weather events and changing habitats for specialized species. These negative impacts of human life and development have been affecting creatures that we do not always think about, insects. These creatures thrive in specific environments and are sometimes highly impacted by pesticides and weather changes. Beneficial insects often play an important role in the ecosystem, pollinating and feeding small animals and other insects. Without insects, especially bees, many fruit trees would not be able to produce food for us. Their impact on the environment is something that is often overlooked. However, their role in the ecosystem will need to be filled with their decline. Pest insects may increase in numbers with the decline of beneficial insects. Due to their size and capabilities, pests can fill ecological niches that are becoming open.

Figure 1: The migration of Monarch Butterflies

Source: https://i2.wp.com/www.conservewildlifenj.org/blog/wp-content/uploads/2016/10/MonarchMap-NatureServe-10_20.png

Monarch butterflies migrate thousands of miles to reach their winter homes in Mexico and California. These insects help pollinate flowers throughout their lives. Educationally they are an important specimen for explaining metamorphosis. Climate change causing great fluctuation in weather events may be causing their decline. Abnormal amountsof precipitation and temperature fluctuations have been theorized for thereason for the decline (1). The insects are very vulnerable, especially with large amounts of rain that makes their wings wet and unable to complete their journey. This decline has been seen in Mexico where the butterflies migrate to in the winter, over from the winter of 2016-2018, the butterflies have shown a decline of 14.8% (1).

Figure 2: Monarch butterflies clumping together on a tree
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 Other theories for their decline include impacts from humans such as pesticide use and habitat destruction (2). Pesticides are often used to kill pest insects, although not always predicted, these chemicals may have negatives effects on adult and larval butterflies, such as death or reproductive decline. Many butterfly species clump together on trees for warmth. However, with habitat destruction, especially logging, butterflies are rapidly losing their native habitat. With the decline of butterflies, more protected areas need to be established to ensure that they have safe habitats to clump together and thrive.

Figure 3: Representative of a pest insect, cockroaches

Source: https://cdn1.i-scmp.com/sites/default/files/styles/1200x800/

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Global warming and climate change have led to heatwaves around the world. Sensitive insects may not be able to cope with the severity of heat waves or the frequency. Surprisingly, the increased heat may have an effect on fertility in male insects. In England, when increased heat applied to fertile male flour beetles, they were shown to produce less offspring or none at all (3). With the continued decrease of insects, the ecological role will most likely be filled by pest insects such as cockroaches.  They are fast breeding and can thrive in warmer temperatures (4). They may also be more resistant against pesticides and other harmful pollutants that other insects are sensitive to. The effects of heatwaves on pests have already been shown. A recent heatwave has caused a drastic spike in bug bite related calls to the NHS (5). Pests like mosquitoes can thrive in warmer temperatures and even become more productive. As heatwaves continue, there will be more pest problems.

Concern for the world’s beneficial insects should be something that is discussed more often. We are seeing a large decline in many insect’s populations. The butterflies migrate with fewer every year. To prevent the further loss of our beneficial insects such as pollinators, action must be taken to conserve their habitats and limit the amount of pollution that we are producing each year. Globally, climate change places stress on many populations with extreme heat and dramatic precipitation. Reduction of pollutants related to the increase in global warming would aid in the protection of these insects. Along with making the environment more suitable for the survival of insects, we should also protect their native habitats and provide areas for migration. As urbanization continues, insects are losing habitat, so areas should be designated in urban areas to ensure that some native habitat is maintained. Even small steps can help maintain populations such as providing certain species of plants that attract butterflies and bees. Providing them food every year encourages them to come back and continue to reproduce. The conservation of pollinators, such as bees and butterflies, is crucial to maintain the ecosystem and prevent the overpopulation of pest insects. Now is the time to take action and reduce our negative impact on the beneficial creatures to aid in their survival.

References

 1.  Monarch butterfly numbers down for second year in Mexico. (2018, March 6). BBC News. Retrieved from https://www.bbc.com/news/world-latin-america-43301123

2. Hannibal, M. E. (2019, January 25). Are We Watching the End of the Monarch Butterfly? New York Times. Retrieved from https://www.nytimes.com/2019/01/25/opinion/monarch-butterfly-california-extinction.html

3. Weintraub, K. (2018, November 13). Male Insect Fertility Plummets After Heat Waves. New York Times. Retrieved from https://www.nytimes.com/2018/11/13/science/sperm-infertility-insects-heat.html

4. McGrath, M. (2019, February 11). Global insect decline may see 'plague of pests'. BBC News. Retrieved from https://www.bbc.com/news/science-environment-47198576

5. Ives, L. (2018, July 15). Heatwave causes spike in insect bite calls to NHS. BBC Health. Retrieved from https://www.bbc.com/news/health-44823286