紐西蘭發現世界最大昆蟲

 

An explorer has found the biggest insect ever on record — so large it can scoff a carrot.
She's called a Weta bug and has a huge wing span of seven inches and weighs as much as three mice.
Former park ranger Mark Moffett, 55, discovered the cricket-like creature up in a tree on New Zealand's Little Barrier Island.
He spent two days searching for the creepy crawly which was thought to be extinct after Europeans brought rats to the island many years ago.
American Mark said, "Three of us walked the trails of this small island for two nights scanning the vegetation for a giant Weta."
"We spent many hours with no luck finding any at all, before we saw her up in a tree."
The giant Weta is the largest insect in the world, and this is the biggest one ever found.
"She enjoyed the carrot so much she seemed to ignore the fact she was resting on our hands and carried on munching away."
"She would have finished the carrot very quickly, but this is an extremely endangered species and we didn't want to risk indigestion."
"After she had chewed a little I took this picture and we put her right back where we found her."
Mark, from Colorado, added: "We bug lovers hear a lot of people who think insects are inferior in some way because of their size, so it was great to see such a big insect.
"This became all the more amazing when we realised that this was the largest insect recorded."

 紐西蘭發現全世界最大的昆蟲，體型是一般蝗蟲的50倍大，且比家裡養的小老鼠還要重3倍之多。

根據《赫芬頓郵報》報導，一名美國的自然觀察家莫菲特（Mark Moffett）在紐西蘭的小巴里耳島（Little Barrier），發現一隻「全球最大」的巨沙螽，重達71公克，比麻雀和小老鼠還要重，而且還會吃胡蘿蔔，模樣相當驚人。

莫菲特說，這是自己看過最大的昆蟲，不過因為巨沙螽是一種瀕危的物種，所以拍照留念之後，莫菲特又將巨沙螽放回大自然。

巨沙螽在紐西蘭共有70多種，以其他小昆蟲、水果為食。之所以體型如此巨大，是因為巨沙螽這個物種生存近2億年，一直沒有進化，保持巨大的外型至今。

小知識：

目前已知的昆蟲，體長大都不超過30公分。昆蟲體型的小巧和牠們體表的
外骨骼與呼吸系統有很大的關係。外骨骼可以抵抗外在壓力以維持昆蟲體型，
外骨骼如果長得太大，其承受壓力的能力將會降低。此外，昆蟲是以氣管
行擴散作用來呼吸，如果氣管太長，氧氣與二氧化碳將無法有效率的運送。
基於以上原因，昆蟲才無法長得太大。

下面我自己的補充：

1. 外骨骼支撐力與厚度成正比，厚度跟體長一次方成正比，重量與體長立方成正比
   於是當體長變為兩倍，重量增為八倍，因此動物都有體型最大限制

2. 除了氣管因素以外，昆蟲因為是開放式循環系統，交換效率遠不如閉鎖式循環系統
   體型稍微大一些，循環路徑變長，運輸效率就來不及