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Cannibalism¹ Quells² Contagion³ among Caterpillars⁵

同类相食可防治传染病

Ben Van Allen collects caterpillars.

本 范 艾伦喜欢收集毛毛虫。

While doing postdoctoral research at Louisiana State University,

在路易斯安那州立大学做博士后研究的时候，

Van Allen saw that some of the caterpillars were having others for lunch.

范艾伦发现一些毛毛虫会把同类当午餐吃掉。

Rather than cry over his losses, Van Allen took advantage of the cannibalism for his research.

范艾伦没有为这一发现感到难过，而是利用这种同类相食的现象来进行研究。

“Generally speaking, it’s nutritious⁶ to eat the same species,

“一般来说，把同类当成食物吃是很有营养的，

because they have all the nutrients⁷ that are already inside you, so it’s an easy-to-process meal.”

因为它们含有你体内的所有营养，因而可以说它们是易于消化吸收的食物。”

“It also reduces the amount of competition you are going to experience –

“这种行为也会为你减少竞争对手——

it’s just one fewer individual trying to eat the same food you are, in the same area.

毕竟吃掉一个同类就意味着少了一个在同一地区和你争抢同一种食物的对手。

And it’s usually easy to find members of the same species too, since they live in the same place you do.”

而且由于大家都生活在同一个地方，所以通常也很容易看到同类。”

Van Allen and colleagues collected the caterpillars to study disease transmission in lepidoptera—moths and butterflies.

范艾伦和他的同事们收集了这种毛毛虫来研究鳞翅类物种——蛾类和蝴蝶——的疾病传播。

After observing the cannibalism they wondered

在对这种会同类相食的物种进行了观察之后，

if their subjects’ appetite for each other might be dangerous for the individual—if it ate an infected cousin—

他们很好奇这种生物进食同类的喜好会带来何种影响，假设某个个体吃掉了一个患有传染病的同类，那么这对这个个体来说是否应该是危险的，

but benefit the group—by removing the infected individual from the population.

而对种群来说则是有益的——因为它将传染者消灭了。

“Our main point is that, while that is an individually risky⁸ thing for a cannibal,

“我们的主要观点是，尽管这对个体来说是件冒险的事，

as populations are more cannibalistic, they actually prevent diseases from getting into the population in the first place.”

但由于这类生物变得更愿同类相食，这实际上从一开始就预防了传染病进入该种群。”

Van Allen’s study is in the journal American Naturalist⁹.

范艾伦的研究发表在《美国自然主义者》杂志上。

It was released at the same time as a study in the journal Nature Ecology & Evolution that showed

与此同时，在《自然生态与进化》杂志上发表的一项研究表明，

that chemicals produced by plants can ward¹⁰ off caterpillars, by inducing the caterpillars to eat each other instead of the plants.

植物产生的化学物质可以防治毛毛虫，诱导毛毛虫去吃同类而不去吃植物。

“It would be kind of an ironic¹¹ thing,

“这会是一件很有讽刺意味的事。

if a disease was coming into this caterpillar⁴ population and the plants caused them to become more cannibalistic

如果一种疾病本应该进入这种毛毛虫种群，然而由于这些植物使得毛毛虫变得更愿同类相食，

and that prevented the disease from coming in and actually ended up worse for the plant than it was in the first place.”

从而阻止疾病进入该种群，最后导致最终情况对这些植物来说更糟。”

Worse for the plant because the cannibal behavior caused the caterpillar population to wind up up healthier—and hungrier.

之所以对这种植物来说会变得更糟，是因为同类相食的行为最终会导致毛毛虫变得更加健康，也更加饥饿。

中英对照听力原文

Cannibalism Quells Contagion among Caterpillars

同类相食可防治传染病

Ben Van Allen collects caterpillars. While doing postdoctoral research at Louisiana State University, Van Allen saw that some of the caterpillars were having others for lunch. Rather than cry over his losses, Van Allen took advantage of the cannibalism for his research.

本·范·艾伦喜欢收集毛毛虫。在路易斯安那州立大学做博士后研究的时候，范艾伦发现一些毛毛虫会把同类当午餐吃掉。范艾伦没有为这一发现感到难过，而是利用这种同类相食的现象来进行研究。

“Generally speaking, it’s nutritious to eat the same species, because they have all the nutrients that are already inside you, so it’s an easy-to-process meal.”

“一般来说，把同类当成食物吃是很有营养的，因为它们含有你体内的所有营养，因而可以说它们是易于消化吸收的食物。”

“It also reduces the amount of competition you are going to experience – it’s just one fewer individual trying to eat the same food you are, in the same area. And it’s usually easy to find members of the same species too, since they live in the same place you do.”

“这种行为也会为你减少竞争对手——毕竟吃掉一个同类就意味着少了一个在同一地区和你争抢同一种食物的对手。而且由于大家都生活在同一个地方，所以通常也很容易看到同类。”

Van Allen and colleagues collected the caterpillars to study disease transmission in lepidoptera—moths and butterflies. After observing the cannibalism they wondered if their subjects’ appetite for each other might be dangerous for the individual—if it ate an infected cousin—but benefit the group—by removing the infected individual from the population.

范艾伦和他的同事们收集了这种毛毛虫来研究鳞翅类物种——蛾类和蝴蝶——的疾病传播。在对这种会同类相食的物种进行了观察之后，他们很好奇这种生物进食同类的喜好会带来何种影响，假设某个个体吃掉了一个患有传染病的同类，那么这对这个个体来说是否应该是危险的，而对种群来说则是有益的——因为它将传染者消灭了。

“Our main point is that, while that is an individually risky thing for a cannibal, as populations are more cannibalistic, they actually prevent diseases from getting into the population in the first place.”

“我们的主要观点是，尽管这对个体来说是件冒险的事，但由于这类生物变得更愿同类相食，这实际上从一开始就预防了传染病进入该种群。”

Van Allen’s study is in the journal American Naturalist.

范艾伦的研究发表在《美国自然主义者》杂志上。

It was released at the same time as a study in the journal Nature Ecology & Evolution that showed that chemicals produced by plants can ward off caterpillars, by inducing the caterpillars to eat each other instead of the plants.

与此同时，在《自然生态与进化》杂志上发表的一项研究表明，植物产生的化学物质可以防治毛毛虫，诱导毛毛虫去吃同类而不去吃植物。

“It would be kind of an ironic thing, if a disease was coming into this caterpillar population and the plants caused them to become more cannibalistic and that prevented the disease from coming in and actually ended up worse for the plant than it was in the first place.”

“这会是一件很有讽刺意味的事。如果一种疾病本应该进入这种毛毛虫种群，然而由于这些植物使得毛毛虫变得更愿同类相食，从而阻止疾病进入该种群，最后导致最终情况对这些植物来说更糟。”

Worse for the plant because the cannibal behavior caused the caterpillar population to wind up up healthier—and hungrier.

之所以对这种植物来说会变得更糟，是因为同类相食的行为最终会导致毛毛虫变得更加健康，也更加饥饿。