By Don Glass
Y: I could have sworn that I heard a strange tapping sound in my house last night. It was faint but chilling. I think there must be a ghost in my house.
D: Do you happen to keep caterpillars, perhaps the hook-tip moth?
Y:Why? Yes, I do. I have several little creatures. But what does that have to do with that tapping noise I heard?
D:That noise probably came from your caterpillars, and it probably means one of them invaded another's territory.
Y:I didn't know caterpillars were territorial.
D:Well, it turns out some are. In fact, what’s odd is that the hook-tip moth’s territorial behavior is much like that of many vertebrates, not what you’d expect in an organism like a caterpillar. These caterpillars find themselves a good leaf, and then they construct a nest of silk to protect them while they feast. When another caterpillar intrudes upon the resident caterpillar’s territory, the resident caterpillar stops eating, retreats into its nest, and it makes tapping noises by dragging or striking its mandibles against the leaf.
Y:What does the intruder do?
D:Often the intruder makes the sound as well and may end up attacking the resident’s nest by biting through some of the silk strands. Caterpillars don’t make this noise anywhere but in the nest, and scientists say this behavior suggests that the rivals are sizing each other up. They also suggest that the sounds may function to attract the attention of predators, in which case the intruder would be rather defenseless.
毛蟲的敲擊聲
Y: 我發(fā)誓昨天晚上在家里我聽到了很奇怪的敲打聲。那個聲音微弱至極,但就是讓人毛骨悚然。我家里是不是有鬼啊!
D: 該不會你正好養(yǎng)了毛蟲,或是鉤翅蛾吧?
Y: 啊?嗯,我有養(yǎng)。我養(yǎng)了很多小動物。但那跟我晚上聽到的聲音有什么關(guān)系呢?
D: 那個聲音很可能就是你養(yǎng)的小毛蟲發(fā)出的。很有可能是一只小蟲闖進(jìn)了另一只的領(lǐng)地。
Y: 我都不知道毛蟲還有領(lǐng)地呢!
D: 呃,有的是這樣的。事實上,奇怪的是,鉤翅蛾的占地行為更像是脊椎動物,并不像是你所想像的蛾類的占地行為。這些毛蟲為自己找到一片好葉子,然后用絲筑一個巢。在毛蟲“用餐”的時候,這個巢就可以起到保護作用。當(dāng)另一只毛蟲闖入該毛蟲的領(lǐng)地時,“原住民”會立即停下用餐,退回巢內(nèi),借助拖拽鄂骨或是用鄂骨敲擊葉子發(fā)出敲擊聲,以此威脅入侵者。
Y: 那么,入侵者又會怎么做呢?
D: 通常情況下,入侵者同樣也會制造出敲擊聲,到最后會咬掉“原住民”巢內(nèi)的部分絲線。毛蟲只會在巢內(nèi)發(fā)出這樣的聲音??茖W(xué)家指出,這是雙方在衡量對方的實力。同時,還指出,這種聲音還會吸引來食肉動物,在這樣的情況下,入侵者在防御上就會處于明顯的弱勢。
Notes: hook-tip moth 鉤翅蛾