Massive Loss Of Insects And Insect-Eating Animals In Puerto Rico Rainforest Linked To Climate Change


Insects are crucial to the survival of many plant and animal species because they serve as food and pollinators.

Findings of new research, however, highlight a threat that these creatures face amid rising global temperatures.

In a new study published in the Proceedings of the National Academy of Sciences on Monday, Oct. 15, researchers revealed that the insect population of a national forest in Puerto Rico has significantly dropped.

Study researchers Brian Lister, from the Rensselaer Polytechnic Institute in New York, and Andres Garcia, from the National Autonomous University of Mexico, attribute the massive loss of these tropical invertebrates to climate change.

They also found that the crash in the number of bugs also appears to restructure the food web of the rainforest as the number of insect-eating animals such as frogs, birds, and lizards has also decreased.

The researchers have reasons to believe that the massive loss of tropical insects has something to do with warmer temperature. In the same period of the arthropod crash, the average temperature in the rainforest rose by 2 degrees Celsius.

Temperatures in the tropics are relatively consistent and the invertebrates that thrive there are adapted to these temperatures. Because bugs cannot regulate their internal heat, they fare poorly outside of their natural environments.

A grasshopper sits on top of a flower.
Featured image credit: Pixabay

“We compared arthropod biomass in Puerto Rico’s Luquillo rainforest with data taken during the 1970s and found that biomass had fallen 10 to 60 times,” the researchers wrote in their study.

“Over the past 30 years, forest temperatures have risen 2.0 °C, and our study indicates that climate warming is the driving force behind the collapse of the forest’s food web.”

The study supports the recent warnings from the United Nations Intergovernmental Panel on Climate Change about the severe environmental threats posed by a 2 degree Celsius increase in global temperature.

The Luquillo rainforest in the study already reached or even exceeded the 2 degree Celsius increase in average temperature, and the findings show that the consequences are potentially catastrophic as other animals in the food web are also affected.

The researchers said that the effects of climate change in tropical forests may even be worse than previously thought.

“The insect populations in the Luquillo forest are crashing, and once that begins, the animals that eat the insects have insufficient food, which results in decreased reproduction and survivorship and consequent declines in abundance,” Lister said in a press release, which was published by the Rensselaer Polytechnic Institute.