Environmental Effects on Insect Development

Climate Change

• Climate change has the potential to affect insect development in different ways, depending on the species. Increased temperatures cause many insects that develop rapidly during warmer temperatures to develop even more quickly, thus resulting in a yearly increase in insect populations. Higher temperatures can also cause parasites to move through life stages more quickly, reducing parasitism. Insects that live underground may be less affected by rising temperatures because temperature changes are less apparent in soil than in air. On the other hand, warmer winters also decrease insect mortality. In cases where high temperatures cause farmers to stop growing certain crops, insects that feed on those crops may experience population reductions. Insect predators may also experience population booms, which could reduce certain insect populations. Despite the potential of climate change to reduce insect populations, increasing temperatures are more likely to create larger and more diverse insect populations.

Rainfall

• One result of climate change is more severe weather, including heavier rainfall. Although rising temperatures can cause insect populations to boom, severely heavy rainfall can actually decrease insect populations. Heavy rainfall can kill insects that live in the soil by flooding; insects that live on plants and eggs laid on leaves are washed away by heavy rains. On the other hand, fungal pathogens that infect insects thrive in high humidity environments, and their increase could negatively affect insect populations by killing insects and eggs, or by stunting their development.

Carbon Dioxide

• Rising carbon dioxide levels are also associated with rising temperatures. Higher levels of carbon in the environment can increase the ratio of carbon to nitrogen; because insects require high levels of nitrogen to survive and develop properly, increased carbon dioxide levels can negatively affect insect development and also make insects more susceptible to parasites.

Pollutants

• Pollutants negatively affect insect development by decreasing the stability of the ecosystems where they live. Air pollution and acid rain both cause destruction to the forests that are homes to many insects. Mercury poisoning is another culprit in insect deaths. If a pollutant wipes out a species that is crucial to the survival of an ecosystem, all members of that ecosystem are affected. The food chain may be disrupted as well. Although increased rainfall and temperatures can be harmful to insect populations, insect communities can often tolerate natural changes. However, pollutants can adversely affect all species within an ecosystem.