In the insect world, the stick insect with a longest body size of more than 60 centimeters has been found to be undoubtedly a "big man". Importantly, the evolutionary journey of this insect, the stick insect, predates us by more than 200 million years! Moreover, to this day, they are still active around humans with a variety of mimetic skills, which is really impressive.
In the insect specimen display area of the Cognitive Museum of Gansu Agricultural University, there is a collection of Malaysian stick insects, which was once known as the world's longest stick insect. Li Longfeng, an associate researcher at the College of Life Science and Technology of Gansu Agricultural University, has many years of research on the stick insect, here, the small science fans will follow the interpretation of teacher Li, together to explore the past and present life of the stick insect, to see what skills this "big man" has?
Dental foot spurs
Malay yellow skirted stick insect
Flat bamboo worm
01
The earliest fossil record of stick insects dates back to the Permian
Familiar insects of the order Stick insects, commonly known as stick worms, dry wood sticks or leaf worms. Stick insects usually inhabit the branches quietly during the day and only come out at night to find delicacies, and the leaves of the plant are their favorite food, so the stick insects are truly vegetarians. The earliest fossil record of stick insects dates back to the Permian period (299 million to 254 million years ago).
So far, a total of 40 species of Mesozoic bamboo carcass fossils have been published in the world, 6 families, 20 genera, distributed in 10 countries, mainly in Russia, Kazakhstan, Kyrgyzstan and China. In 1997, Professor Ren Dong of Capital Normal University published a new family, the xiū family, which opened the prelude to the study of chinese bamboo worm fossils. This is also the first bamboo worm fossil found and reported in China, and the specimen is from the Late Jurassic to Early Cretaceous Yixian Formation formations in western Liaoning and northern Hebei, China. Representatives of this family are the fossil treasures of the strange gods and the giant strange gods.
Bamboo worm fossils: A strange god B huge strange specimens preserved in the Capital Normal University Teacher Li Longfeng provided pictures
02
The camouflage and defense skills of the stick insect
If the stick insects in ancient times have been superbly mimetic, then the current stick insects have played the mimetic skills in an all-round way. Mimesis is very common in insects and can occur at all stages of eggs, larvae, pupae or adults.
The mimicry of the eggs is more pronounced: they have a variety of shapes, hard shells, and brown or dull yellow colors on the surface, resembling the seeds of a plant. Stick insects have a variety of spawning methods, some eggs stick to the leaves, some are laid in the plant, and some are scattered on the surface of the forest, mixed in the deciduous grass, making it difficult to identify natural enemies.
According to the research of many scholars, compared with eggs, the mimetic defense mechanism of nymphs and adults of arthropods is more perfect.
Look for it, where am I? Infographic
1. Concealment
The body color of the stick insect is often green or brown, and its color will also change with humidity, temperature, the intensity of light, and the color of the stem or leaf of the plant, thus integrating the entire body with the surrounding environment and avoiding predators.
2. Mimesis
Some of the young nymphs of the stick insects bend the entire abdomen from the back to the front of the head to simulate the posture of mosquitoes or scorpions, thus deterring predators.
3. Swing
Nymphs and adults of some species of stick insects can swing their bodies from side to side, like branches or leaves swaying in the wind.
4. Active escape
When frightened, some stick insects quickly fall from their stems and successfully escape under the cover of surrounding plant debris or leaves.
5. Suspended animation
Most species of stick insects exhibit suspended animation when disturbed or captured by predators.
6. Show
When frightened, some stick insects will quickly raise their front and back wings, showing some bright colors or patterns, and suddenly change from a calm hidden state to a pseudo-warning color with a frightening effect.
7. Vocalization
When some stick insects spread their wings, the friction of the anterior gluteal area of their forewings and hindwings will make a sound to strengthen the intimidation effect.
8. Automatic limb amputation
The spines on the leg joints of some taxons can be used as a defensive tool to stab predators. In addition, the stick insect can also automatically break its limbs, if it is caught by a predator, it will automatically break its limbs through the violent contraction of the muscles, leaving the broken leg to the predator and then escaping. But don't worry, it will grow new legs.
9. Defensive secretions
Many species of stick insects can secrete and spray secretions or emit strange odors to confuse and repel predators.
What do you think! The superb mimetic ability that the stick insect has acquired in the long evolutionary journey of nearly 300 million years is not very impressive.
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In ancient times, it has a superb ability to mimic
Through the study of more than 200,000 fossil specimens, the researchers identified a new species of the pantheon family, the black band, which is produced in the Yixian Formation of Wicker Gou Village, Ningcheng County, Inner Mongolia. The discovery and research of the black-banded insect not only allows people to understand the morphological characteristics of the primitive taxa of the order Stick insects, but also vividly reveals the mimetic phenomenon of ancient stick insects.
The fossil specimen of black belt is preserved in the Capital Normal University, courtesy of teacher Li Longfeng
From the living stick insects and leaf insects, we can appreciate the wonderful performances of these mimetic masters and defense experts, but most of them are a kind of visual mimesis, that is, the dominant factor of mimesis is the color and shape of the body and wings. The same is true of the stick insects in the fossils, and by looking at the black-banded fossils, the researchers found that its forewings and hindwings have a straight and parallel dark vein sequence at the top of their forewings, forming a cover with tongue-shaped wings and coherent dark lines, thus covering the abdomen and blending with the environment.
After comparison, the researchers found that a leaf-like plant organ in the Rehe biota is very similar to the black banded plant, which not only has a similar size to the black banded tree, but also has 3 fork-like branches, each leaf is long and narrow, the longitudinal veins are significant, and the rest of the leaf is difficult to distinguish from the covered rock, which indicates that the texture of the leaf is thin and transparent, which is very similar to the texture of insect wings.
It can be seen that the black belt can use a variety of plant organs to hide itself and avoid predators. The black-banded mangothus lived in the early Days of the Rehe biota, and many potential insect predators have been documented in the habitat at that time, such as small anti-birds and diverse mammals. In this way, a small circle of life is formed: predators try their best to hunt and kill black belts, and black belts use plants to hide themselves while eating plants to avoid natural enemies, and constantly improve this superb imitation ability that is both diverse and enduring.
Long knowledge
Incomplete metamorphosis: refers to the fact that insects only pass through three periods of eggs, larvae and adults during ontology. Adults and larvae have similar living habits and do not differ much in form, except that the larvae are small, their reproductive organs are not mature, and their wings are not fully developed in the form of wing buds. Gradual metamorphosis is a type of insect that is not fully metamorphosed.
Complete metamorphosis: refers to the insect's ontological development, through four stages of eggs, larvae, pupae and adult worm. Fully metamorphosed larvae and adults differ significantly in morphological structure and life habits.
Written by Xia Miao, chief reporter of Lanzhou Lanzhou Morning Post