Bug Antifreeze
Ever seen a cricket wearing a parka? Probably not, but you might have wondered how insects make it through the winter! After all, they’re cold-blooded, so their body temperature is pretty close to the temperature around them! Why don’t bugs turn into popsicles?
Well, some do, of course. In a lot of insect species, only one stage is adapted to live through winter cold. For example, in some species, only those in the pupa stage, wrapped in insulated cocoons, can stay warm enough to survive. Other bugs, like mosquitoes and grasshoppers, don’t survive the winter themselves, but they lay their eggs in deep water or soil that won’t freeze hard. As long as their environment doesn’t freeze, the eggs will hatch in the spring.
Some adult insects and spiders actually do live through the winter, either by burying themselves deep in the ground, where the temperature is more moderate than the air temperature, or, of course, by moving into warm buildings!
Most bugs survive the winter’s cold by undergoing diapause, or insect hibernation. No one knows whether bugs in diapause actually sleep, but most are totally inactive. Like animal hibernation, diapause drastically lowers a bug’s metabolism, allowing it to survive all winter on its stored-up body fat.
Many diapausing bugs can survive even if their body temperatures drop below freezing. How? By making their own antifreeze! In diapause, insects’ bodies produce different types of alcohol. The alcohol in the bug’s system lowers the freezing point of its body fluids. This natural antifreeze lets many insects survive winter’s below-freezing temperatures, and wake up to make even more bugs next spring!
小蟲防凍秘招!
你見過蟋蟀穿皮大衣嗎?應(yīng)該沒有吧,但你或許想知道昆蟲們是怎樣度過冬天的。畢竟它們都是冷血動物,那它們的體溫應(yīng)該和周圍環(huán)境差不多??蔀槭裁蠢ハx們沒有凍成冰棍呢?
當(dāng)然啦,有一些昆蟲會凍成冰棍。對于很多昆蟲來說,它們只有處于某個特定的階段才能活過寒冷的冬天。比如說,有些昆蟲只有處于蛹期,被隔熱的繭包裹起來時 才能維持足夠的熱量以存活。而另一些昆蟲,比如蚊子和草蜢,它們本身無法在冬天里存活,但它們會把卵產(chǎn)在深水處及泥土中,而這些地方并不會完全凍住。只要 所處的環(huán)境不結(jié)冰,這些蟲卵就能在春天孵化。
一些成蟲,還有蜘蛛則依靠自身便能在冬天存活。它們要么將自己深埋在地底,因為那里的溫度可比空氣中溫和得多。要么搬到到暖和的建筑當(dāng)中居住。
大多數(shù)昆蟲通過滯育,即蟲類冬眠,來度過寒冬。沒人知道滯育中的昆蟲是否真的熟睡,但大多數(shù)昆蟲處于完全不動的狀態(tài)。就像動物冬眠一樣,滯育能大幅減緩昆蟲的新陳代謝,這樣一來昆蟲們便能憑借自身體內(nèi)儲存的脂肪度過整個冬天。
許多滯育中的昆蟲即使體溫降至冰點以下依然能夠存活。這是怎么做到的?因為這些昆蟲能自己生產(chǎn)“防凍劑”。當(dāng)處于滯育當(dāng)中時,這些昆蟲體內(nèi)會產(chǎn)生多種不同 的乙醇。這些乙醇使得昆蟲體液的冰點降低。這種天然的防凍劑使得許多昆蟲在氣溫低于冰點的冬天得以存活。當(dāng)它們于春天醒來時,甚至能繁殖出更多的幼蟲。