Nobody is ever amused to see tiny insects scurrying around in their homes, especially if it’s an insect capable of flying (hint: flying cockroaches). But insects’ ability to fly is actually quite extraordinary as they are the only group of invertebrates that have evolved wings and flight. As per general observations, many insects can fly. However, certain insects have evolved to be flightless and are losing the ability to fly altogether, particularly on islands. Here, you would see a moth crawl and a fly walk.
According to Phys, on small islands between Antarctica and Australia, almost all insects are flightless. Rachel Leihy, a PhD candidate from Monash University School of Biological Sciences, says that Charles Darwin had hypothesised wing loss of island insects and that “he knew about it” even back then.
She continues, "He and the famous botanist Joseph Hooker had a substantial argument about why this happens. Darwin's position was deceptively simple. If you fly, you get blown out to sea. Those left on land to produce the next generation are those most reluctant to fly, and eventually, evolution does the rest. Voilà." Joseph Hooker and other scientists weren’t entirely convinced by Darwin’s facile logic and believe that Darwin may have been wrong.
Research shows insects are losing the ability to fly in windy regions
A new Australian study suggests that Darwin was correct even though his reasoning wasn’t on target. Researchers found that flightlessness in island insects occurred so that they could focus more of their energy on reproduction.
Before arriving at that conclusion, biologist Rachel Leihy and Professor Steven Chown of Monash University analysed data on insects battered by strong winds in the Southern Hemisphere often called, ‘roaring forties’ and ‘furious fifties’. These winds tear across the ocean and islands between Antarctica and Australia - where the researchers conducted the study.
As spoken about earlier, on these islands, flies walk and moths crawl due to their diminished or absent wings. It’s quite strange to imagine, isn’t it? However, it’s all done to conserve energy that would be required to fly in windy regions, therefore the bugs are better off staying on the ground rather than fighting the winds. Eventually, these island insects stop producing wings and wing muscles and redirect their energy to reproducing - the key to the survival of their species.
Rachel, the lead author of the paper, says, “It's remarkable that after 160 years, Darwin's ideas continue to bring insight to ecology.” Professor Steven Chown concluded that overall, the Antarctic region was a great laboratory for such an experiment and has the potential to help scientists find answers to other on-going mysteries as well.