毛毛虫变身冰棍挺过严冬(下)

In case you’re not familiar with glycerol, it’s a natural alcohol compound.

以防你不熟悉甘油，说明一下，甘油是一种天然的酒精化合物。

It works similarly to when we salt city sidewalks to keep them from becoming icy.

甘油的工作原理类似于我们在城市人行道上撒盐以防结冰。

The compounds in the woolly caterpillar’s body lower its freezing point, buying it some time. And then they do something even more remarkable.

毛毛虫体内的这种化合物可以降低体内冻结点，争取一些时间，让它可以做一些更了不起的事情。

They move water out of their cells so that it freezes in the extracellular space.

它们将水脱离出细胞，使其在细胞外空隙结冰。

That’s because ... Water of course gets bigger when it turns to ice.

那是因为……水结成冰时体积自然会变大。

And so if a cell was filled with water, and it froze, then it could bust the cell membrane, and that would really harm the caterpillar.

如果一个细胞里满是水且结冰了，那么细胞膜就会遭到破坏，这会危及毛毛虫的生命。

So getting the water out of the cell is a good idea, and lowering the temperature at which the liquid freezes is also a good idea.

将水排出细胞是一个好主意，降低液体结冰温度也是一个好主意。

So these little guys can freeze solid all winter and then thaw out and get up and walk away come spring.

这样，这些小家伙整个冬天都会冻得扎扎实实，到了春天，解冻、苏醒、四处爬动。

They can actually freeze and thaw multiple times over the course of a winter.

实际上，在冬季，它们会经历多次结冻与解冻。

But there’s an energetic cost that comes to falling asleep and waking back up again.

但是入睡与苏醒是个耗精力的活儿。

Studies of the Isabella tiger moth have shown that they can in fact undergo several freeze thaw cycles, but it’s really not great for them.

对伊莎贝拉虎蛾(毛熊毛虫)的研究表明，它们实际上可以经历几轮结冻与解冻，但这对它们来说并不好。

It’s better if they can freeze, stay frozen and then thaw at the end of the winter.

如果它们在冬季开始时结冻，保持这个状态，待到冬季结束时再解冻，那就更好了。

And not only that ...I think there’s also some damage that happens to some of the structures in the caterpillar.

不仅如此……我认为毛毛虫的部分结构也会受到一些损伤。

Some of the more delicate parts, I think, can be damaged a little bit.

我认为，一些比较脆弱的部分可能会有损伤。

And the more times they have to freeze, thaw and refreeze, the more likelihood that they'll be a little worse for wear at the end of the winter.

毛毛虫结冻、解冻、再结冻的次数越多，冬天结束时就越有可能遭受严重的损耗。

And this gets worse because of things like climate change.

由于气候变化等原因，情况愈发糟糕。

If we have winter heat waves or warm periods when caterpillars that had been in the deep freeze, thaw out and then freeze again, there was some concern that they wouldn’t be able to go back and forth between these conditions.

如果遇到冬季热浪或冬季温暖期，毛毛虫必须深度结冻、解冻、然后再次结冻，人们担心它们无法在这样的环境下自由变化。

That’ll also lead to larger ecological implications.

这也会导致更大规模的生态影响。

Caterpillar populations and therefore butterfly or moth populations could take a hit if the overwintering survival is interfered with by these interludes of warmer weather that prevent them from getting through their wintering period in the same way that they had before.

如果越冬生存受到这些穿插的温暖天气的干扰，进而阻止它们像以往一样越过冬季，那么，毛毛虫、蝴蝶、蛾子的数量可能会受到打击。

And that might have more profound impacts than we think.

这可能会产生比我们想象的更深远的影响。

We already know that some important pollinators, like bees and butterflies, are struggling to survive due to all kinds of human activities.

我们已然知晓，由于各种各样的人类活动，一些如蜜蜂与蝴蝶等重要的传粉昆虫正在艰难生存。

Caterpillars are important just because they’re such cool animals, but they also are a phase of the life cycle of lepidopteran, so moths and butterflies.

毛毛虫至关重要，因为它们很厉害，它们是鳞翅目昆虫生命周期的一个阶段，蛾与蝴蝶也是如此。

They are pollinators; they’re herbivores; they're food for birds and other organisms.

它们是传粉昆虫; 是食草动物; 鸟类和其他生物以它们为食。

And they’re just part of what makes the world fun to look at and live in.

它们让这个世界丰富多彩、趣味横生。

For Scientific American’s Science, Quickly, I’m Kate Furby.

感谢收听《科学美国人》科学快报，我是凯特·弗比。