Insects around the world are expected to be thrown into chaos by the effects of man-made climate change. Changes in temperatures may throw off their delicate interactions with plants and other insect species, possibly causing widespread pest outbreaks.
According to a paper published in the journal Ecology Letters on June 20, increased temperatures from climate change are predicted to impact insect communities and their interactions with the lifecycles of the plants they rely on, possibly leading to the loss of important species in the future.
"Climate change is going to have multifaceted effects on insect communities and whole ecosystems," Thomas H.Q. Powell told Newsweek. Powell is a co-author of the paper and an assistant professor of biological sciences at Binghamton University, State University of New York.
The authors found that the balance between insect species and their predatory wasps may be thrown off-kilter by climate change, with different species declining or succeeding based on how resilient they are to change. Unfortunately for us, those most resilient are often pest species like locusts or ips beetles, and the species that control them tend to be less robust.
"Decoupling of seasonal timing between parasitoids and their hosts or differences in their ability to shift their ranges in response to climate change could lead to widespread outbreaks of pest insects that are otherwise ecologically controlled by these tiny but important wasps," Powell explained.
In the paper, the authors investigated how two diverging populations of hawthorn fly were impacted by changing temperatures. In New York's Hudson Valley in the 1850s, one population continued to eat the fruit from hawthorn trees, while another shifted to eating from apple trees.
Due to the difference in fruiting times of these trees, the reproductive schedules of the two populations shifted, which in turn impacted several species of parasitic wasps that feed on the maggots of the hawthorn fly.
The authors tested how the changing climate might impact these species in the future, by raising populations of apple- and hawthorn-based flies and parasitic wasps under conditions matching the seasonal average from the last 10 years of climate data. They then tested under warmer conditions matching those projected 50 to 100 years into the future.
In the study, the authors found that the hawthorn-eaters were more resilient to temperature shift, while the apple-eaters were thrown out-of-phase with trees in the future temperature scenario, possibly due to having less genetic diversity. The life cycles of parasitic wasps were found to be unaffected by the heat, which would lead them to fall out of sync with the hawthorn flies, and other species that they prey upon.
"One overall group of insects that we expect may be in particularly precarious positions are parasitoid wasps, which play incredibly important roles in ecosystems in controlling populations of plant-feeding insects, including agricultural pests," Powell explained.
Similar issues might arise with insect species around the world, as the delicate web of species interactions is thrown out of sync. Exactly which species will be worst impacted is hard to predict, as such small changes as the tree they like to eat from can change how resilient they are in the face of changing temperatures.
"Resilience in the face of climate change involves three different components: how a population responds physiologically to the acute stress, the context of that response within its ecological community, and the potential for rapid evolutionary adaptation to these new conditions. Here, we found that the first part may come down to the specifics of how temperature interacts with developmental processes," Powell explained to Newsweek.
"Even for populations as closely related as the apple and hawthorn flies in our study, the relationship between temperature change and important development tipping points may be very different.
"One general prediction we can make is that these problems are likely to be most severe for species that are ecological specialists. Insects that are adapted to narrower niches are simply going to have less margin for error. When it comes to which species or subspecies may be able to mount rapid evolutionary responses, the key ingredient for this is genetic diversity.
"Natural selection is a powerful force, but it can only act on existing variation in genes underlying adaptive traits. This is where other aspects of anthropogenic (environmental) change may greatly exacerbate the long-term effects of climate change.
"Species that are already suffering from land-use change, habitat loss, and habitat fragmentation may have the hardest time keeping pace with our rapidly changing world," Powell said.
"There are certainly some species that do better under warmer temperatures as these conditions could allow faster development, more generations of offspring produced in a single year, or more food available," Alycia C.R. Lackey told Newsweek. Lackey is an assistant professor of insect ecology at the University of Louisville, Kentucky, and a co-author of the paper.
"Species with wide tolerances for temperature variation and those able to withstand higher mean temperatures or hotter heat waves will be more resilient to climate warming."
Many of the species that could be impacted include those which are crucial to the function of our economy.
"Many pollinators, including bees, butterflies, and moths, are important for our crops and enjoyment of our natural areas and are severely threatened by climate warming. On the flip side, many crop pests may do better under climate warming and further threaten agricultural yields," Lackey said.
According to the authors, one of the ways to mitigate these impacts on insects is to limit the progression of climate change.
"Along with doing everything we can to limit the acceleration of climate change itself, we need to make sure species and ecological communities have a fighting chance to self-correct in the face of a warming planet," Powell said.
"Maintaining as much intact habitat space and connectivity among those habitats as possible is essential for allowing ongoing evolutionary processes to keep pace with the multifaceted stresses posed by climate change.
"The window for doing these things is rapidly closing though, which is why efforts like the 30x30 initiative (to protect 30 percent of the world's land and ocean area by 2030) are so critical."
Do you have an animal or nature story to share with Newsweek? Do you have a question about insects? Let us know via nature@newsweek.com.
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Newsweek is committed to challenging conventional wisdom and finding connections in the search for common ground.
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Jess Thomson is a Newsweek Science Reporter based in London UK. Her focus is reporting on science, technology and healthcare. ... Read more
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