Uncovering the Impact of Climate Change on Insect Evolution
Key Highlights :
As the world continues to evolve, different species of organisms are taking divergent paths and evolving in different ways. But what happens when climate change is added to the mix? That is the question that Thomas H.Q. Powell, assistant professor of biological sciences at Binghamton University, State University of New York, and his lab seek to answer in their recently published paper, "Contrasting effects of warming in diverging insects," in Ecology Letters.
In the 1850s, the apple maggot fly—a major agricultural pest—began to diverge into two populations in the Hudson Valley. One population continued to live on the fruit of the region's native hawthorn trees, while the other shifted to a new food source: apple trees, which were originally introduced to North America by English colonists. This shift in food source resulted in a shift in the two populations' reproductive schedules, which had an impact on several species of parasitic wasps that feed on the maggot fly, demonstrating the delicate balance that undergirds ecosystems.
To study the effects of climate change on insect evolution, the researchers reared populations of apple- and hawthorn-based flies and parasitic wasps under conditions matching the seasonal average from the last 10 years of climate data, and then warmer conditions projected 50 to 100 years into the future. The results of the experiment showed that although the two fly populations were in the same location, they responded to the temperature shift in starkly different ways. The hawthorn-dwellers appeared to have more resilience, possibly owing to more genetic diversity. The lifecycle of the apple flies was thrown out-of-phase with their host plant, making their survival tenuous—potentially halting the speciation process. The life cycles of parasitic wasps weren't affected by the heat, which could spell dire consequences if they fall out of step with their prey's lifecycle.
The results of the experiment have important ramifications for insect biodiversity, as they demonstrate the need for natural adaptation in order to restore balance in disrupted systems. However, there are major constraints on rapid evolution, as habitats tend to be smaller and fragmented, limiting the amount of genetic variability that organisms need to respond to evolving pressures.
The study shows that the effects of climate change may be completely different, even for identical flies from the same habitat that have been evolving since the 1800s. This could lead to widespread chaos in the ecological timing of insect communities in the coming decades. It is clear that further research is needed to uncover the full impact of climate change on insect evolution.
