Source: Science and Technology Daily
Bright red body color pygmy red dragonfly provided by the interviewee
The reporter learned on November 23 that when Zhao Li, director of the Huaxi Entomological Museum in Chengdu, Sichuan Province, sorted out the specimens, he found that among the batch of dragonfly specimens collected by the museum from the Jinkouhe area of Leshan, Sichuan province in August this year, there was the world's smallest dragonfly species, the pygmy red dragonfly, which was the first time that the species had been recorded in Sichuan.
"The pygmy red dragonfly is recognized worldwide as the smallest dragonfly species, mainly distributed in southeast Asia and the tropical regions of southern China, and is the 'dwarf' of dragonflies. This is not only the first time that the species has been recorded in Sichuan, but more importantly, the world's smallest dragonfly since recorded in this batch of specimens has also been found, and its body length is less than 15 mm. Zhao Li said that in the south of China and Southeast Asia are distributed dwarf red dragonflies.
So how mini is the pygmy red dragonfly? As "dwarfs" in their natural environment, how do they survive and reproduce? In this regard, the reporter of Science and Technology Daily conducted an interview.
Less than 20 mm in size
"The Great Atlas of the Chinese Dragonfly records that the body length of the pygmy red dragonfly is 17 to 19 mm, of which the average body length of male adults is 18.5 mm and that of females is 17.5 mm. The length of the pygmy red dragonfly collected in the Sichuan region this time is generally about 17 mm, and the shortest body length is less than 15 mm. Zhao Li said that according to the classification, the dwarf red dragonfly belongs to the insect class Dragonfly family Red Dragonfly genus, "The red dragonfly genus has only 5 species in the world, and the dwarf red dragonfly has been discovered in 1842." ”
Why is it that the shortest dwarf red dragonfly found this time is not within the normal range of the record?
"Probably because their habitat has an islanded tropical environment, allowing this population to evolve independently here, so it will be different from the size of the pygmy red dragonfly in other regions." Zhao Li analyzed that this is the northernmost known distribution of this species in China, so this pygmy red dragonfly population is likely to be a separately evolved population.
At the same time, according to the "Chinese Dragonfly Large Atlas", the length of the single hindwings of the males of the pygmy red dragonfly is about 12 to 13 mm. Zhao Li told reporters that the length of the single hindwings of the male males found this time is only about 11 mm, which is slightly smaller than recorded.
According to reports, the male of the pygmy red dragonfly is as its name suggests, and the whole body, including the eyes, is bright red, which is easy to distinguish in the green plants. However, the female of the dwarf red dragonfly is wearing a yellow-brown "windbreaker" and looks very personable.
It is well known that dragonflies are natural flying masters, but the pygmy red dragonfly is not more skilled because of its petite size. "It has been observed that they only move within a radius of a few meters, and even if they are disturbed, they only fly to a place two or three meters away, and then after a while they will return to their original location and stop." Zhao Li said.
According to reports, the largest known dragonfly in the world is called helicopter bean, and its wings can spread up to 19.1 cm, and its body length can reach about 12 cm.
In addition, according to the data, the giant veined dragonfly that lived in the Carboniferous Period (about 300 million years ago) could reach a wingspan of 75 cm, but the giant veined dragonfly was extinct in the early Permian (about 250 million years ago).
One side raises insects in the soil and water
As the first discovery of the pygmy red dragonfly in Sichuan, the Jinkouhe area of Leshan belongs to the alpine canyon landform, the highest point of the mountain range on both sides of the canyon is more than 3000 meters above sea level, and in the bottom area of the canyon at an altitude of 500 meters to 800 meters, the annual average temperature is higher than that of the surrounding areas. Zhao Li believes that the discovery of the pygmy red dragonfly in this place is inseparable from the natural environment and climatic conditions of the region.
"As an indicator insect of the ecological environment, the distribution, density and number of pygmy red dragonflies in an area can measure the natural environmental conditions of the area." Zhao Li told reporters that at present, the number of pygmy red dragonflies in China has dropped sharply, and the existing number has been very rare, and its appearance can show from the side that the ecological environment of this place, especially the water environment, is very good.
It is understood that the pygmy red dragonfly generally lives in wet grass paddy fields, or in some small ponds. Zhao Li found them in a puddle full of weeds by the river, and observed their intersection. "They have a short time to intercourse, only two or three minutes, and after mating, they will rest a little and lay eggs in the nearby water." He said that the feathering of the pygmy red dragonfly (that is, the process of pupa turning into a worm) occurs in the second half of the night or morning, and its larvae climb from the water to the grass, the time to prepare for feathering is very short, only about 20 minutes, and if you are not careful, the observer will miss the process of feathering. "Other species of dragonflies generally have to prepare for at least a few hours after they emerge from the water before they begin to feather."
The reporter learned that the feathering process of dragonflies takes two or three hours. After feathering, they will stay in place and wait until more than ten hours later before they can fly normally. Miraculously, the newly feathered adult pygmy red dragonfly is relatively light in color, and the color will gradually deepen over time, and the male will eventually turn into a beautiful bright red.
It is worth noting that the bright red male pygmy red dragonfly has a sense of territory and will always guard a body of water, which is often the most suitable place for breeding. In general, males who are able to occupy the most favorable places in the breeding environment are more likely to gain the favor of females.
At present, there are more than 5,000 kinds of dragonflies found in the world, and china has now discovered more than 990 species of dragonflies, more than 100 kinds more than the second place Brazil, which is the country with the most veritable dragonfly species.