Dragonflies are carnivorous insects that mainly feed on mosquitoes and flies. They have survived on Earth for hundreds of millions of years, and their flying ability is superb, earning them the title of "king of flying."
Dragonflies were among the first insects to live on this planet. They have been around long enough to perfect their remarkable art of flying and develop excellent hunting skills. Dragonflies are found almost everywhere in the world, especially in hot and humid tropical regions.
Adult dragonflies emerge in a variety of colors, ranging from metallic to pink. Compared with other insects, dragonflies are huge, with some wingspans reaching 16 centimeters, and even the smallest species have a wingspan of 2 centimeters.
The oldest dragonfly fossils discovered date back to around 320 million years ago, indicating that dragonflies appeared much earlier than dinosaurs.
At that time, the oxygen content of the Earth's environment was much higher than it is now, and as a result, the dragonflies in that period were much larger than they are now. For example, the early Permian dragonfly fossils discovered in the United States had a wingspan of an astonishing 0.71 meters.
Currently, the largest dragonfly in the world is a species found in Central and South America, which can reach a length of 19.1 cm. Its head is black with brown eyes that have a greenish tint.
Although its length cannot compare with the dragonflies found in ancient times, they are now extinct. The species to which this dragonfly belongs is the largest of the Odonata surviving in modern society.
There are few species in the animal kingdom that can compare with dragonflies in terms of flying ability. They have two very thin wings but are controlled by strong muscle fibers in the thorax, which enables them to fly in any direction, including horizontally and backward, and to stand still in one position in the air for a minute or more.
Besides being extremely agile flying animals, they are also among the fastest insects. Dragonfly wing muscles function best when they are warm, and if it's cool, the insects often flap their wings to generate heat before they actually take off.
The speed and agility of the dragonfly make it one of the most efficient flying predators. Dragonfly prey is usually small flying insects, but some dragonflies regularly eat prey equal to about 60% of their body weight.
Few insects can lay eggs in salt water, with the exception of some dragonflies. They can reproduce successfully in water with high salinity. This extraordinary ability has evolved over millions of years as their habitat mainly consists of salt marshes, mangroves, and salt lakes.
Odonata insects are rich in resources and play important roles in many aspects. As a representative type of aquatic organisms, their larvae can monitor water environmental pollution.
Some species contain active substances that can be used as medicinal materials, and because their bodies contain abundant protein, amino acids, and minerals, they have great potential for development as an edible resource.
Dragonflies are basically harmless to humans, but some species, such as the dragonfly with large eyes, are known to eat mosquitoes and flies. We should regard them as beneficial insects and consider them as our friends.