When we mention global warming victims, most of us would first picture polar bears struggling on melting ice. But to some biologists, insects such as coastal butterflies also belong to the league of conservation icons.
“If you want to know how organisms react to climate change, it is important to find out how insects react to climate change,” said Dr. Jessica Hellmann, conservation biologist at the University of Notre Dame, explaining that most of the multicellular living organisms in our world are insects.
Despite the usual pest control we humans love to implement on bugs, some of them also have a good side. Insects are food sources to species in higher trophic levels and have an economic impact on crops and timber by helping flowers pollinate, which nearly 80 percent of the world’s crop plants need.
Yet, currently these invertebrates have become the hidden sufferers of global warming. As cold blooded organisms, insects cannot regulate their own body temperatures, making them particularly sensitive to climate change.
In order to test insects’ reaction to warming climate and likelihood of moving north, Dr. Shannon Pelini, Hellmann’s then doctorate student, designed a laboratory experiment to test Pacific Coast butterflies’ reaction to temperature change.
In growth chambers, the caterpillars of two butterfly species—Erynnis propertius and Papilio zelicaon—were exposed to the replicated climates and plants that occur across the butterflies’ usual living range from southwestern Oregon to Vancouver Island of Canada.
They started the experiment with caterpillars because “you have to look at them over their life stage,” said Hellmann.
