Insects "sleep" all winter. How and when do they wake up in spring? You may think that insects will wake up naturally when the weather warms up. It seems that temperature is the most important condition. In fact, it is not that simple.
(1) Drink enough water before waking up
Before insects wake up in spring, the most important thing is to drink enough water first. In order to lower the freezing point before winter and avoid freezing to death, insects expel most of the water. During the winter, insects consume some water; they lose too much water in their bodies. It hinders normal physiological activities, and activities cannot be resumed even when the weather warms up. They use the body's epidermis, respiratory system, digestive system and other water-absorbing organs to absorb as much water as possible, and do not start activities until the water required for body activities is sufficient. If the spring is too dry and it doesn't get enough moisture, it can cause massive mortality. Someone has conducted such a survey and found that the overwintering mortality rate of corn borers is generally around 50 to 60%, and more than half of them die due to excessive water loss in spring. The overwintering eggs of the cotton bug will hatch in early May if the air humidity is above 60%. If there is insufficient moisture or it does not rain for a long time, it will not hatch and will not hatch until it rains.
(2) Food stimulates awakening
The overwintering and awakening time of insects vary greatly depending on the species. Generally speaking, species with few generations in a year and simple food will spend the winter early; species with many generations or complex food habits will spend the winter later. The time of awakening is not only related to their living habits, but also closely related to the growing season of the food they need. Aphids that spend the winter in eggs will break through the egg shells and emerge to suck the juice from the young shoots as soon as the desired host begins to germinate. Therefore, the host's germination time becomes a signal for aphids to hatch.
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