A recent study reveals that oxygen availability is not the primary factor determining the enormous size of insects. The oxygen-delivering tubes in the flight muscles of insects occupy only about 1 percent of the total muscle volume. With oxygen’s role deemed secondary, scientists are now exploring other possibilities to understand the mystery behind the massive size of ancient insects. Kathmandu, April 26.
Approximately 300 million years ago, Earth was home to insects much larger than those seen today. At that time, species like dragonflies had wingspans reaching up to 27 inches. For decades, scientists believed that this giant size was due to atmospheric oxygen levels being about 45 percent higher than current levels. However, a new study published in the journal Nature challenges this long-held assumption.
A fresh analysis of oxygen and respiratory systems shows that insects’ breathing mechanisms differ from our lungs; tiny tubes called tracheal systems distributed throughout their bodies supply oxygen. Research led by Associate Professor Edward Snelling of the University of Pretoria found that the oxygen-delivering tracheae in insect flight muscles make up only about 1 percent—or less—of the total muscle volume.
This evidence confirms that oxygen availability is not the main factor driving insect size. The true secret behind their gigantic size remains unresolved. With the diminished importance of oxygen, researchers are now considering alternative explanations. Some scientists suggest that the emergence of new predators or the physical limitations imposed by insects’ external skeletons may have caused their size to decrease. Much more research is needed to uncover the real secret behind these ‘giant’ insects. (Source: Science Daily)
