◎ Li Di Science and Technology Daily reporter Sheng Li
The reporter learned from the Huaxi Entomological Museum in Chengdu, Sichuan on the 23rd that when the museum director Zhao Li sorted out the specimens, he found that among the batch of dragonfly specimens collected from the Jinkouhe area of Leshan, Sichuan in August this year, there was the world's smallest dragonfly species - the pygmy red dragonfly, which was the first time that the species was recorded in Sichuan.
"The pygmy red dragonfly is the 'dwarf' of dragonflies. This is not only the first time that the species has been recorded in Sichuan, but more importantly, the specimens also contain the smallest dragonfly individual since the world record. Zhao Li said that the pygmy red dragonfly is distributed in southern China and Southeast Asia.
So how "mini" is the pygmy red dragonfly? As "dwarfs" in the natural environment, how do they survive and reproduce? In this regard, the science and technology daily reporter interviewed Zhao Li, director of the museum.
The dragonfly with the weakest flight ability
"The Great Atlas of the Chinese Dragonfly records that the body length of the pygmy red dragonfly is between 17 and 19 mm, while the body length of the pygmy red dragonfly specimen collected in the Sichuan region 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. "There are only five species in the genus, and the pygmy red dragonfly was discovered in 1842."
Why is it that the shortest dwarf red dragonfly found this time is not within the normal range of the record?
"Maybe this is a separately evolved population, but because there is an islanded tropical environment in this place, this population has evolved independently here, forming a different size from other regions of the pygmy red dragonfly." Zhao Li conjectures, perhaps, because this is the northernmost known distribution record of the species.
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 pygmy red dragonfly is just like its name, and the male insect is bright red all over the body, even the eyes, so it is easy to see it in the green plants. However, the male and female insects of the pygmy red dragonfly have different body colors, such as knowing etiquette, "there is a difference between men and women", and the female insects wear "yellow-brown" trench coats, which is very personable.
As we all know, dragonflies are natural "flying masters", but pygmy red dragonflies do not be agile because of their small size. "Compared to some dragonflies, the pygmy red dragonfly's ability to fly is the weakest of the dragonflies I know. It has been observed that they only move within a radius of a few meters, and even if disturbed, they only fly to a distance of two or three meters, and then after a while they will return to their original location. He said.
At present, the world's largest dragonfly is the helicopter bean, its wings can reach 19.1 cm, the body length can reach about 12 cm. However, if you compare it purely by body length, another dragonfly called Lucretia Bean Lady can reach a body length of up to 15 centimeters.
In addition, the Giant Veined Dragonfly, which lived in the Carboniferous Period (285 million years ago), has been recorded to have a wingspan of up to 75 cm, and the Giant Vein Dragonfly was extinct in the early Permian (about 290 million years ago).
Dragonflies "dot water" is laying eggs
As the first discovery of the pygmy red dragonfly in Sichuan, the Jinkouhe area of Leshan is a high mountain canyon, the natural environment is very superior, due to the obstruction of the canyon, the average annual temperature of this place is higher than that of the surrounding area. 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.
"The pygmy red dragonfly can be used as an indicator insect of the ecological environment, and its distribution, density and number in an area can measure the state of the natural environment in the area." He told reporters that at present, the number of pygmy red dragonflies has dropped sharply in China, and the existing number has been very rare, which may be related to the destruction of the wetland environment everywhere. With its appearance, it can be said that the ecological environment of this place is very good, especially the water environment.
Pygmy red dragonflies generally live in moist grassy paddy fields, or in small ponds. This time, it was found by Zhao Li in a puddle full of weeds by the river, and their intersection was also observed at that time. "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.
As we all know, the term "dragonfly points water" does not go deep enough to describe doing things, but do you know why dragonflies order water? It is understood that the dragonfly dot water is actually laying eggs, and the eggs will hatch into larvae before they can feather into dragonflies.
Zhao Li said that according to records, the feathering of the pygmy red dragonfly occurs in the second half of the night or morning, its larvae climb from the water to the grass, and the time to prepare for feathering is very short, only about 20 minutes, and if you are not careful, you will miss the process of observing its 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 where they are 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 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 territorial nature and will always guard a body of water, which is often the most suitable place for breeding. Generally speaking, males who can occupy the most suitable breeding place can 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 dragonflies in the world.
Source: Science and Technology Daily Image courtesy of the reporter
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Source: Science and Technology Daily