# 30 Swarming Locusts

Is a locust the same as a grasshopper? If you said yes you are right. Locusts are about two inches long. They have large heads, four wings, and two large eyes. Each locust weighs about two grams.

How can you tell when locusts are around? Their thrumming sound gives them away. They have no vocal cords. They make sound this way. They rub their hind legs on their front wings. This rubbing causes their wings to vibrate. The action is somewhat like playing a violin.

By itself, a locust is practically harmless. But in a swarm, watch out. Locusts are very destructive. There are two reasons for this. First, each locust, pound for pound, eats 60 to 100 times as much as a human being. One million locusts each day eat as much as 20 elephants or 500 people. Second, a moving swarm may carpet the ground almost solidly. There may be 30 to 60 locusts per square yard. One swarm near the Red Sea covered 2,000 square miles. That's almost the size of the entire state of Delaware.

Locust swarms are like a cloud. They can block out the light of the sun. Railroad trains have been stopped by them. Swarms have covered tracks for miles. Soon their crushed bodies made the tracks too slippery. The train wheels just spun around. There was no traction. Swarms on roads are even worse. Try driving over one. It is similar to driving a car on solid ice.

Locusts fly with great speed, and their endurance is amazing. Swarms have been seen as much as 1,200 miles from land. These swarms are doomed. They tire and drop into the water. There they make rich food for fish. One swarm that started from West Africa did reach England.

# 30 成群飛蝗

蝗蟲和蚱蜢是一樣的嗎？如果你說是，那你就對了。蝗蟲大約兩英寸長。牠們有大頭、四隻翅膀和兩隻大眼睛。每隻蝗蟲重約兩克。

你如何知道蝗蟲在附近？牠們發出的嗡嗡聲會暴露行蹤。牠們沒有聲帶。牠們是這樣發出聲音的。牠們用後腿摩擦前翅。這種摩擦使牠們的翅膀振動。這個動作有點像拉小提琴。

單獨一隻蝗蟲幾乎無害。但成群結隊時，就要小心了。蝗蟲破壞力極強。有兩個原因。首先，每隻蝗蟲，按重量計算，吃的食物是人類的60到100倍。一百萬隻蝗蟲每天吃的食物相當於20頭大象或500個人。其次，移動的蝗群可能幾乎完全覆蓋地面。每平方碼可能有30到60隻蝗蟲。紅海附近的一個蝗群覆蓋了2,000平方英里。這幾乎是整個德拉瓦州的面積。

蝗群就像雲一樣。牠們可以遮蔽陽光。火車曾因牠們而停駛。蝗群覆蓋鐵軌數英里。很快牠們被壓碎的身體使鐵軌變得過於滑溜。火車車輪只是空轉。沒有抓地力。道路上的蝗群更糟。試著開車壓過牠們。這類似於在堅冰上開車。

蝗蟲飛行速度極快，而且牠們的耐力驚人。有人在離陸地1,200英里處見過蝗群。這些蝗群註定滅亡。牠們疲憊不堪，掉進水裡。在那裡，牠們成了魚類豐富的食物。有一個從西非出發的蝗群確實到達了英格蘭。