Why are Insects Larger in Warm Climates?

Why are Insects Larger in Warm Climates?

Have you ever noticed that insects are bigger in certain areas over others? Places like Australia and the Amazon rainforest are notorious for large insects and pests. But what is it about these warm climates that yields larger insects?

A Goliath Stick Insect in northern Australia

It’s Not Just Warmth

Warmth is not the only requirement to yield the resulting growth in insects. Most desert areas are not flush with insects, yet tropical and subtropical environments are. They key difference here is the access to water.

Amazon Rain Forest

Year-Round Food

The combination of warm climates and moisture provides the perfect prerequisites for an abundance of food year-round. This constant access to nourishment has given many species of insects the ability to grow and flourish over years of development. This phenomenon can be seen in humans, dogs, and pretty much all creatures on Earth. If a being is fed poorly over the years or lacks proper nutrition, it will not be able to properly grow and develop, whereas consistent access to a species food source allows them to thrive. This can be seen in other pest situations such as the large populations of rats of sizable stature in cities where they can easily access dumpsters and homes for food. For insects this ideal environment for food and growth is typically met by areas along the equator, leading to larger insects being found in Central America, Southern America, areas of Africa and Asia, and Northern Australia.

Effects of Climate Change

Effects of the gradual warming of the planet are being felt across the globe, including in the world of insects. Researcher and biologist Christine Picard of the Indiana University-Purdue University Indianapolis School of Science has been studying the changes in insect development and migration due to these changing temperatures. In a press release, Picard explained that “as temperatures change and increase, the distributions of these insects will continue to change as well.” This means that larger insects will begin to migrate away from the overheating areas to find new environments that meet their temperature and moisture requirements – the effects of which we are already seeing next door to us in Indiana. “We found it in multiple samples, and we decided ‘oh wow, this fly is here, it has made its way up,” said Picard in response to the new species of fly, L. cuprina, appearing in Indiana from Southern states. “There is definitely a northward movement of species.” …unfortunately, with our close proximity to Indiana, we may be seeing new and bigger bugs soon too…

Citations

  Warmer climates bring more insects, and those insects can bring illnesses (2018) Medill Reports Chicago. Northwestern University. Available at: https://news.medill.northwestern.edu/chicago/warmer-climates-bring-more-insects-and-those-insects-can-bring-illnesses/ (Accessed: September 27, 2021). Why are insects bigger in tropical areas? (2019) The Naked Scientists. University of Cambridge. Available at: https://www.thenakedscientists.com/articles/questions/why-are-insects-bigger-tropical-areas (Accessed: September 27, 2021).