The soil "house" on the windowsill is about 30mm
Early autumn and early winter, the ground is clean and the leaves are withered, causing crops and insects that are moving on the ground to disappear. Is it frozen to death by the cold climate? No, but things are not that simple. In fact, whenever winter comes, most insects enter the winter period and no longer move.
Insects do not have the saying that hibernation. No matter how many generations of insects can occur in a year, when environmental conditions are unfavorable to them, there will be a period of stagnation in growth and development. This period is often in the hot summer or the cold winter, so this period is usually called summer or winter.
Preparation for insects before wintering is started when the climate starts to cool in late autumn and the temperature drops to 8℃~10℃ on average. They first eat themselves and then squeeze out the moisture in their bodies...
1. Food and moisture
The first step in preparation for wintering is of course to eat frantically, accumulate nutrients, and gradually increase the fat content in the body. When you stop eating, the body's fat content reaches its highest level. At the same time, other tissues in the body are constantly storing protein and carbohydrate . The accumulation of these substances can compensate for the substance consumed during the wintering phase of metabolism of .
Secondly, it is to reduce the moisture in the body. Under normal living conditions, the water content in the insects is very high, generally about 70% to 80% of their body weight, which means that most of the weight of the insects’ entire body is water.
Insects have two types of water: one is called free water , and the other is called combined water . Free water is obtained by insects from food and the atmosphere, and is generally not directly involved in a series of biochemical changes in the body. This kind of water is more likely to freeze. When the temperature drops below zero, the insect's body will easily freeze and cause death. It is different when combined with water. It not only participates in a series of biochemical changes in the insects, but also does not freeze at minus ten degrees or even minus thirty degrees, which improves the insect's cold resistance.
The first phase of drainage is to discharge all food residues from the digestive tract before the insects stop feeding and turn to the winter state, and some free water is discharged from the body. Although insects stop feeding and no longer introduce water from the outside world, the metabolic effect in the insects is still very strong, and some water will be discharged with the evaporation during breathing. At the same time, due to changes in the external environment such as climate and light, a series of biochemical changes in the insects are also prompted. During this change, some free water is converted into combined water. The water lost during this stage generally accounts for 20% to 25% of the total water loss. The second period of water loss occurs when the temperature drops to 8℃~9℃. At this time, insects usually enter hidden places for wintering, but have not yet entered the real wintering state. During this period, they have lost 1% to 4% of the water.
2. Temperature versus humidity versus humidity versus body temperature change process
In the preparation before winter, there is another process of changing versus versus versus . Insects are warm-changing animals, and their body temperature changes with the temperature. When the weather is hot, they hide in cool places and when the weather is cold, they run to warm places. This phenomenon of going to a warm place is warming, and it is an important instinct for insects to survive the severe winter. For example, heterochromatic ladybug , which specializes in aphids , when the weather gets colder, they scramble to warmer places such as wall cracks, haystacks and warehouses to spend the winter. The larvae of kowtow worm that live in the soil and spend the winter in the soil, when the weather gets cold, they drill deep into the soil. This is because the soil temperature below 10 cm is more than 7℃ higher than the atmospheric temperature, and the depth at 20 cm is more than 10℃ higher. When the soil depth reaches 60~90 cm, the temperature remains unchanged day and night; when the depth reaches 12 meters, it remains lukewarm and hot. Although most insects do not drill as deep, it is still common to drill 10 to 15 cm. Since the soil temperature is higher than the atmospheric temperature, insects are of course not likely to be frozen to death.
There are also some types of insects that need to drill under the bark, in the trunk, or in the dead branches and leaves in the fields and forests to spend the winter, which is also a manifestation of warming tendency. Generally, the temperature in the bark or deeper bark gap is 2℃~5℃ higher than the atmospheric temperature; in places 2 cm deep in the tree trunk, the temperature is 5℃~6℃ higher than outside.
Wettability is also a survival instinct of insects. Although insects remove most of the free water in their bodies before wintering, in desert arid areas, the evaporation amount of water in the body and surrounding environment of insects in wintering period is much higher than that of recycling, which is extremely unfavorable to maintaining the physiological activity of the insects, especially on the awakening after wintering. Therefore, this is why some insects (especially adults who spend the winter on the surface) often choose to spend the winter under relatively humid objects such as dead branches, fallen leaves, garbage, etc. before wintering.
3. The pupa form and egg form
Different types of insects have different ways of wintering. 43% of them spend the winter in larval form, 29% of them spend the winter in pupa form, 17% of them spend the winter in adult form, and 11% of them spend the winter in ovary form.
Most of the insects that have passed the winter in larval form are almost mature. This is because the first instar larvae that just hatched from the eggs have a tender body wall and extremely poor cold resistance; the second instar larvae are in the stage of rapid feeding and vigorous development. The body cavity contains a lot of water and does not store enough fat required for wintering, so the first and second instar larvae are still not adapted to spending the winter. Insects that pass through the larval stage, in addition to the physical conditions for larvae, it is also essential to choose different wintering places and weave protective covers of various shapes. mayfly , stone fly and dragonflies aquatic insects will become larvae in winter. Unlike other insects, they will not rest in winter, but will actively feed to ensure that they become adults again in early spring. They are energetic and can migrate to warm waters when needed. There is evidence that they themselves produce glycerol to avoid being frozen.
There are not many types of insects that have passed the winter in the form of a pupa. This is because although the pupal skin is relatively hard and can protect you from wind and cold, it has been living a static life for a long time after all, and at this stage it lacks the ability to avoid natural enemies such as birds and beasts, parasitic insects. Various butterflies spend the winter in the form of pupa. Before entering hibernation, the last generation of butterflies chooses a secluded, sunny, and wind-shaded environment to crawl on fences, walls, etc. First spit out some silk to stick the tail to the object where you live, and then rely on the body's peristalsis and the effect of peeling hormone to take off your old clothes and become a pupa that has lost its ability to run. If there is a natural enemy invasion at this time, their only demonstration will be to shake their bodies a few times. Moth pupae mostly spend the winter in the underground soil. As long as the soil is not damaged by winter plowing and overturning land or feeding from poultry and livestock, they can spend the winter safely.
Most insects can feed during adult stages, or have hard body walls. As long as they eat their stomachs, store enough nutrients for winter consumption, and choose a good place to spend the winter, they can survive the long winter. Most of the mosquitoes and flies in Diptera spend the winter in adult form. Every year when winter is coming, they go to dark windproof corners such as stone caves, greenhouses, empty rooms, and livestock houses to hide and spend the winter. Ant Social insects like dig the cave deep enough to the point where the cold can’t reach it, where they enjoy the food accumulated in summer.
, while another social animal, bees, has evolved an adaptation mechanism different from ants. When the hive temperature drops below 17℃, bees will gather into a ball, and the bees inside will vibrate their wings to obtain heat, while the bees outside will protect the heat from being lost like an insulating layer, and the bees will take turns to enjoy the internal heat.
Insects that spend the winter in the form of eggs, common ones include locust , cricket , aphids, whiteflies, planthoppers, spotted cicadas, blind bugs, etc.
Bohai Bay migration channel location
Of course, if you really can't stand the cold winter, insects have another choice, that is, to migrate, like migratory birds, to fly to warmer areas to avoid bad living environments. For example, eastern Asia is located in the monsoon zone, and its southern airflow in spring and summer and northern airflow in autumn form airflow conditions for insects to migrate north and south from generation to generation, and to migrate seasonally from long distances. my country is located in a typical East Asian monsoon climate zone, providing favorable conditions for cross-regional migration of pests.
So, in order to survive, creatures will always do their best to find the right way, even if they are weak insects, they can cope with the cruel environment.
"house" is like this, there are adults and pupae, and the middle chamber is a noble "room".
speculation: Because some soil on the balcony may seep out of the soil when watering the flower pot, it is cold in late autumn, and these more than ten insects keep carrying soil liquid, climbing onto the widest bottom edge on the inside of plastic steel window (there is also a glass outside to protect the wind and rain), using its own combined water to pile up the soil layer by layer, and make three "houses" of partitions as needed. It is simply a three-bedroom balcony, a big villa in the insect world!
The insect's location is clever: there is a glass outside to block the wind and rain.
From the structure of the "house" in front, the insects divide the "villa" into three bedrooms, with adults (dried) and pupa. The middle chamber is a noble "room", which is well sealed (not opened now, I don't know who the "house owner" is inside). The last adult sacrificed himself to complete the final closure of the building, that is, to use his own insect body to block the "big villa" to build the final gap, so that the inside and outside are completely separated. In the end, this bug is the most dedicated. There are three or two adults living in the rooms on both sides, but they are already dry. Maybe it’s because they are tired of building a house! It seems that there is not much nutrient when you see the dry insect body. Such a large project is not easy to complete. Perhaps this is the unified mission of the biological world. For the sake of the future, all energy must be used to complete the mission!
4. How to wake up?
Insects "slept" for a winter. How do you wake up in spring and when will you wake up? You may think that when the weather is warm, the insects will wake up naturally, as if temperature is the most important condition, but it is not that simple.
(1) Drink enough water to wake up
Before the insects wake up in spring, the most important thing is to drink enough water first, because in order to lower the freezing point before winter, insects discharge most of the water, and consume some water during winter. Too much water loss in the body hinders normal physiological activities, and even if the weather is warm, they cannot resume activities. They use the body's epidermis, respiratory system and digestive system to absorb water, and try to absorb water as much as possible, and only start to move when the body needs enough water. If spring is too dry and you can't absorb enough water, it will cause a lot of death. Someone has conducted such a survey. The mortality rate of corn heartworms overwinter is generally around 50-60%, and more than half of them die of excessive water loss in spring. The overwintering eggs of cotton three-point blind bugs can hatch in early May if the air humidity is above 60%. If the moisture is insufficient or it does not rain for a long time, it will not hatch and will not hatch until it rains.
Common insect rooms, but I don’t know that this is the Mantis’s home
(2) Food stimulation wakes up
The overwintering and awakening time of insects is very different due to different species. Generally speaking, there are few algebraic species that occur in the year and are simple in winter earlier; there are many generations or complex diets, and the winter is later. In addition to being related to their living habits, the time of awakening is mainly closely related to the growing season of the food required. Aphids that spend the winter with eggs, as long as the host needs to start sprouting, they will break through the egg shell and boat out to suck the juice of the buds. Therefore, the time of the host's germination becomes a signal of aphid hatching.
Professional information of this article is compiled from: Popular Science China, please indicate the source when reprinting.
