The world’s largest orchid grows several meters tall. The tiniest is practically invisible. Some bloom high up in trees, while others live underground. All in, there are around 28,000 species of orchid on earth – about as many as all the bird, mammal and reptile species combined. They grow all over the world, bearing every imaginable colour, shape, and pattern. And there’s a cunning purpose behind these elaborate displays: many orchids trick insects, sometimes even into having sex with them.
世界上最大的蘭花 可以高達數公尺。 最小的則是小到根本看不見。 有些蘭花在高聳的樹上開花, 有些則生長在地面上。 總的來說,地球上有 大約兩萬八千種蘭花—— 等同於鳥類、哺乳類,及爬蟲類 全部加起來的物種數目。 蘭花在世界各地都會生長, 有各種能想像出來的 顏色、形狀、花紋。 蘭花之所以有如此多樣的呈現, 背後其實有著巧妙的目的: 許多蘭花會欺騙昆蟲, 有時甚至騙昆蟲和它們性交。
Like other flowers, most orchids need to attract insects to gather their pollen and carry it between plants. But unlike most flowers, which attract a range of pollinators with sweet nectar, these masters of deception deploy other tactics– like pretending to be an insect’s mate, letting off alluring scents, and mimicking the appearance of other species.
和其他的花一樣, 大部分的蘭花也需要吸引昆蟲 來採集它們的花粉, 在植物間傳播。 但,和大部分的花不同的是, 大部分的花會用甜美的花蜜 來吸引多種傳粉昆蟲, 而身為欺騙大師的蘭花 則採用其他戰略—— 比如,假扮成昆蟲的配偶, 釋放出誘惑的氣味, 以及模仿其他物種的外表。 蘭花最有趣的手法之一, 就是「性欺騙」。
One of their most intriguing methods is sexual deception. Through a combination of sexy shapes and pheromones, orchids convince insects to mate with them. Take the bee orchid, whose petals look almost exactly like the velvety body of a bee. This disguise is so convincing that male bees land on the orchid and try to have sex with it, picking up pollen as they go. Other orchids have evolved contrasting colours and ultraviolet spots– invisible to humans but irresistible to insects. Still others have tactile ‘love-handles’ that ensure insects are positioned precisely for pollination. When a male wasp lands on the hammer orchid, for example, his enthusiastic mating motion flips a hinge in the flower, forcing his body into the pollen. At the next flower he visits, that same hinge pushes his pollen-covered body onto the stigma, fertilizing it. Some orchids make such convincing mates that insects even ejaculate on them, wasting valuable sperm.
透過性感形狀以及費洛蒙的結合, 蘭花能說服昆蟲和它們交配。 以蜂蘭為例, 它們的花瓣看起來簡直 就像是蜜蜂的絲絨身體。 這種偽裝非常有說服力, 會讓雄蜂降落在蘭花上, 試圖和它交配, 在離開時則會把花粉帶走。 其他蘭花則已經演化出 對比色以及紫外線斑點—— 人類無法看見它們, 昆蟲卻無法抗拒它們。 還有其他蘭花具有 觸覺「愛的把手」, 確保昆蟲會剛好停留在 能取得花粉的位置。 比如,當雄性黃蜂 降落在鐵錘蘭上面時, 牠熱情的交配動作, 造成花朵快速擺動, 迫使牠的身體被擺到花粉當中。 等牠去造訪下一朵蘭花時, 同樣的擺動動作會將牠那 被花粉覆蓋的身體推入柱頭, 讓它受精。 有些蘭花假扮的配偶 太有說服力了, 甚至會讓昆蟲在花上射精, 浪費寶貴的精子。 但,性欺騙最重要的要素是氣味:
But the most vital component of sexual deception is scent: orchids mimic the precise scent of a single insect species. This is possible because many insects and flowers produce simple organic compounds called hydrocarbons, which form a layer that protects their bodies from drying out. The precise blend of compounds in this layer is species-specific. Its scent can double as a way for insects to attract potential mates, known as a sex pheromone. Over the course of many thousands of years, random compound combinations have given some orchid species precisely the same signature scent as particular insect species. This matching scent allows them to attract male pollinators who fall over and over again for the flowers masquerading as females of their own species.
蘭花能夠精準模仿 單一種昆蟲物種的氣味。 這是有可能的,因為許多昆蟲和花 都會產生簡單的有機化合物, 叫做碳氫化合物, 它會形成一層膜,防止身體乾掉。 形成這層膜的精確化合物 混合配方,每個物種皆不同。 昆蟲可以把氣味加倍, 來吸引可能的配偶, 也就是一般所知的性費洛蒙。 在數千年的過程中, 隨機的化合物組合, 讓某些種類的蘭花 具有和特定昆蟲物種 相同的特殊氣味。 氣味吻合,就能讓這些蘭花 吸引到雄性傳粉昆蟲, 牠們則會不斷上勾, 被假扮同種雌性昆蟲的 蘭花給欺騙。 蘭花的技倆不只有性欺騙而已。
Sexual deception isn’t the only trick orchids have up their sleeves. Their oldest scam is mimicking the shapes and colours of other nectar-producing flowers— but without the sweet nectar. Some orchids also masquerade as places where insects lay their eggs. One species not only has the colour and appearance of rotting meat; it emits a scent of decay as well– drawing in flies who deposit their eggs on the flower and unwittingly pollinate the plant. Other orchids look and smell just like the fungi on which certain insects lay their eggs.
它們最古老的詐術 是在形狀和顏色方面, 模仿其他會產花蜜的花種—— 只是蘭花沒有甜美的花蜜。 有些蘭花也會橋裝成 昆蟲產卵的地方。 有一種蘭花,不僅有 腐肉的顏色和外觀; 它還會釋放出腐敗的味道—— 吸引蒼蠅在花上產卵, 不知不覺中就協助了異花傳粉。 還有其他蘭花,看起來 和聞起來都像是菌類, 某些昆蟲會在這些菌類上產卵。
Where do all these bizarre adaptations come from? Random genetic mutations in orchids may result in a trait– like a scent or a shape– that, by chance, matches the needs of a single insect species. The huge diversity within the insect world also increases the likelihood that an orchid will find a unique audience. Able to make more seeds and offspring with the help of its dedicated pollinators, the orchid successfully reproduces in isolation, and becomes a new species. But because of their dependence on sometimes just one pollinator species, orchids are also vulnerable, and many quickly go extinct.
這些怪異的適應變化是打哪來的? 隨機基因突變可能是 造成蘭花某種特性的成因—— 比如氣味或形狀—— 且剛好就符合某種昆蟲的需求。 昆蟲世界有著非常高的 多樣性,這點也增加了 蘭花和某種獨一無二的觀眾 成功配對的可能性。 在傳粉昆蟲很投入的協助之下, 蘭花得以產生更多種子和後代, 因而成功地單獨繁殖, 成為新的物種。 但,因為有些時候蘭花 得要仰賴單一種傳粉昆蟲, 它們也很脆弱, 很多種蘭花沒多久就絕種了。
Over time, though, more orchid species have formed than died out, and orchids are some of the most diverse flowering plants. They have such exuberant and otherworldly shapes that they occasionally deceive human senses, too: In their petals we see what appear to be tiny, dancing people, monkey’s faces, spiders, and even birds in flight.
不過,隨著時間, 新形成的蘭花種類比絕種的還多, 且蘭花是最多樣化的 開花植物之一。 它們有著豐富又另類的形狀, 因此有時也能夠欺騙人類的感官: 我們會在蘭花的花瓣上看到 似乎是在跳舞的小人形、 猴子的臉、蜘蛛, 甚至有在飛行的鳥兒。