They are the greatest living power among the animals on this planet: although it is known around one Million species insects, scientists estimate that the actual figure can be 5 to 10 times higherAdding 90 % of all animals and half of the eukaryotic species described (creatures with core cells that include plants and fungi).
Each person hit around 1 400 million insects; They exceeds us 70 times with total weight. There are people who hate or fear them But they are essential in terrestrial ecology. And although they are omnipresent, it would be said in the winter that they disappear from the face of the earth, only to come up again every spring. What do insects do during the cold months? How do they survive the winter?
What do insects do in the winter?
In the past, the idea of spontaneous generation was a very useful source to explain this Enigma; Aristotle believed that the aphids were born from Rocío drops. But because we know that every living creature comes from a different living creature, scientists have to look under the stones, literally to understand how They perpetuate some animals during the months That, in contrast to endoterms like us, they cannot produce their own heat.
The winter ecology of insects is a wide and surprising field for the varied; There is no strategy whatsoever. ‘We are still Unraveling the nuances of why some could be cheaper than othersaccount Brent SinclairEntomologist at the University of Cornell Expert in Winter Biology of Insects.
Almost all conceivable solutions exist in the world of insects, from avoiding the cold to astonish, through the simplest of all: dying; Although, of course, guaranteeing the offspring for the next favorable station. This is the case of wasps, dreaded animals that really only worry at the end of the summer. There is a reason for this: At the end of the warm station, the larvae have already grown and stopped producing the sugary liquid that served as food for the colony. Then the wasps have to look for maintenance elsewhere, and our outdoor meals are very tempting parties.
But even this is not enough to prevent everyone from dying; Hunger, not cold. Unlike bees beehives, Admiperos lasts a single season. AND Only the queen survives, wintering on a hiding placeIn your body keep the sperm from the previous mating to fertilize your eggs until the next spring, launch the next generation of employees and undertake the construction of the new nest.
Flight or resistance
The Queen Wasp strategy is very widespread in the world of insects: Flight of cold looking for a winter careA hole in a tree or under a bed of leaves. The bees appeal to the Bijenkorf and the ants seal the tunnels of the Anthill. “Many simply bury themselves on the floor as far as it’s not that cold,” says Sinclair; “Some, especially invasive vermin, depend on human constructions to survive.” Paradoxically, even snow serves like a blanket that protect freezame insects.
So, so, multitude of insects survives the winter, although hidden in nature, where we cannot see them. Thanks to a hibernation mechanism called Diapause, they do it that slows down his metabolism and stops its development. “They often do not feed or drink the winter, so they have to keep energy and water,” says Sinclair.
But the Diapause requires previous preparation, and this happens during the fall. Many insects have three small simple eyes called Ocellos in their heads that act as light detectors. When the days are shortened, the internal brain clock starts the winter program, a reaction that is strengthened when the temperatures are lower.
In addition to the search for shelter, there is another way to prevent cold for some insect migration. “There are species that cover long distances, especially dragonflies and butterflies,” says Sinclair. The case of Monarch Butterflies (Dana Plexippus), who turn to thousands from the United States and Canada to Mexico, but these movements are more massive than we imagine: A study quantified the winter migration of insects In the south of the United Kingdom in around 3.5 billion, with a mass of 3 200 tons.
There are certain species that see neither emigrating nor resort. They simply limit themselves to supporting temperatures below zero. According to Sinclair: “They have physiological and biochemical mechanisms to survive cold.” These mechanisms include the production of cryoprotective connections, natural antifreeze such as glycerol and certain stress proteins called thermal shock. Some insects, the entomologist continues: “Literally freeze solids“; That specialized biochemistry of his organism prevents ice from destroying his body. Even species that hide from cold usually produce cryoprotectors.
Climate change is a threat
It seems that the increase in temperatures due to climate change will prefer From insects, by saving all these difficult rigs from survival. But experts warn that exactly the opposite can happen. Less snow means poorer insulation of the ground. In addition, and according to the entomologist David DenlingerFrom the state university of Ohio, “sometimes it is not a diapause access that induce the production of cryoprotectors in itself, but the low temperatures.”
In the corn suck, A moth whose caterpillars are a scourge of these cropsThe larvae come in diapause when the days are shortened, but “only when exposed to low temperatures will be tolerant of cold,” says Denlinger. Sinclaire points out that this is happening with other species studied, such as the beetle of the potato or a kind of intestines.
Therefore, if Insects do not receive enough cold stimulans to develop that toleranceThey can die in the winter. And if the winter program is not working properly, insects draw their energy and water reserves too quickly and collapse for hunger or dehydration.
“Loose Warm episodes can fool the insect and let the diapause end too quickly”, Says Sinclair, who says that this can break the synchronization of the cycle: insects arouse when the plants they feed have not yet sprouted. And when insects die, birds that increase in the spring will not find larvae for their chicks. “It is complicated,” concludes Sinclair; “There will be winners and losers.”