All around the world, many groups of animals and plants diverge from each other and take separate paths, before these separate paths eventually result in different evolutionary lineages. But the delicately balanced and intricate roads of evolution in insects might be disrupted by climate change, as a new study found.
The Apple maggot fly is a major agricultural pest in the United States. In the 1850s in the Hudson valley in the state of New York, these flies began diverging into two populations. One group continued to live on hawthorn trees, which were native to the region. The others shifted to what was then a new food source—apple trees introduced to the continent by English colonists.
An experimental study on these two populations published in the journal Ecology Letters identified how climate change can throw a spanner into the works of natural insect evolution.
“The entomologist who discovered this actually corresponded with Darwin about it potentially being an example of the origin of species in real time. It wasn’t until the system was picked back up by researchers in the late 20th century that we found out he was right,” said Thomas Powell, corresponding author of the paper, in a press statement, referring to the early discovery of the two populations. Powell is an assistant professor at Binghamton University in the state of New York in the United States.
According to the university, Hawthorns fruit three or four weeks after apples do. This causes a shift in the reproductive schedules of the two populations. In turn, this has an impact on the different species of parasitic wasp that feed on the maggot fly.
As part of the experiment, the researchers raised different flies and parasitic wasps under conditions that matched the seasonal average from the last 10 years of climate data. After that, they repeated the experiment, but this time with the conditions that were projected for 50 to 100 years in the future, altered by climate change.
The two different populations of flies reacted in two very different ways. The hawthorn-feeding flies were quite resistant to the change, possibly due to the higher genetic diversity amongst them. But the researchers discovered that the lifecycle of apple flies became out-of-phase with their host plant.
This could make it more difficult for them to survive, and therefore, potentially putting a halt to the process that creates more species. Interestingly, the life cycles of parasitic wasps were not affected by the heat. This could have dire consequences for the wasps as well if they cannot sync with their prey’s lifecycle.
