Pesticides Are Making Bees Dumber殺蟲劑讓蜜蜂變笨了

凱特·埃施納

Even if they survive， they might not thrive.雖可存活，恐難繁衍。

You might associate honeybees and bumblebees with their cute， fuzzy shape and seemingly aimless interest in flowers. But beneath the yellow-and-black （mostly） stripes lies an incredible mind. A new study pooled evidence from 23 studies of honeybees and bumblebees： its conclusions， which build on years of bee research， point to the fact that levels of pesticides currently considered safe to use may still have a big effect on bee colony survival.

Although they might look simple， “bees have a very difficult job，” says study author Harry Siviter， a graduate student at Royal Holloway University of London. To efficiently find and collect food to bring back to the hive， worker bees have to quickly learn to recognize （and then memorize） the most effective foraging routes， he says. To top it off， the routes change with the seasons and with other factors. Honey bees even remember which flowers theyve visited recently， so they dont waste time going there again.

All of this takes a good memory and an ability to learn—things that many lab studies have observed in honey bees using the “proboscis extension assay.” When a bee comes near the scent of sugary， delicious nectar， it starts to stick its tongue out. In experiments， researchers exposed bees to pesticides and then watched what they did when prompted to forage， looking to see when—and whether—they stuck their tongues out. Siviter and his colleagues took the data of 23 of these studies and performed a large-scale analysis of the results.

They found that doses of pesticides that are the equivalent of what a bee might encounter in a field “had significant negative effects on learning and memory.” That was true both when bees were suddenly exposed to a lot of pesticide， and when they got a little bit over a long time. It was also true regardless of whether the bees were exposed to neonicotinoids， a class of pesticides that has been around since the 1990s and is being increasingly regulated today， or other pesticides.

Current pesticide regulations are geared toward making sure they arent used at levels that kill bees. But these currently legal amounts apparently make the worker bees dumber， which could have effects for species survival. “Regulation and policy should move toward addressing the sub-lethal effects of pesticides，” Siviter says.

The other question these findings implicitly raise is how these pesticides affect less-studied types of bee. Bees dont all live collectively， University of Guelph scientist Elizabeth Bates told Popular Science in an interview. “Many wild bees do not live in colonies，” she says， “and if their learning or memory are affected， there are no other bees to help out or pick up the slack.”

Ohio State University entomologist Reed Johnson told Popular Science in an email interview， the question is： “Can pesticides ever be used safely around bees？” This study， which in one sense has the strength of 23 studies worth of evidence， “suggests that the answer is ‘no，” he wrote.

The follow-up question goes deep into one of our most fundamental needs—food. Pesticides are an essential part of large-scale industrial agriculture， and some amount of honeybee exposure is inevitable. The question， then—which hasnt been answered by regulation to date， Johnson says—is how much harm to bees is acceptable.

As ever， more research is needed. But this study is worth paying attention to， University of Ottawa bee conservationist Jeremy Kerr told Popular Science. Its conclusions are based on evidence from over 100 individual experiments included in the 23 studies， he says， lending their findings weight. “The lesson that emerges is that honeybees begin to lose their ability to learn and to remember when they are exposed to neonicotinoids，” he writes.

The power of this paper is that it shows “a consensus of knowledge” on this question， he wrote. That result is something pesticide policy-makers could pay attention to. “With restrictions on neonicotinoids increasing globally， many will be looking to alternative chemicals for crop protection，” Bates says. Its important to think about what those chemicals might be doing to the bees.

說起蜜蜂與大黃蜂，你可能會聯想到它們可愛而毛茸茸的身體及其對花朵看似漫無目的的喜愛。然而，它們黃黑相間（大多如此）的條紋之下卻有著令人難以置信的頭腦。一項新研究收集了23項有關蜜蜂和大黃蜂研究的證據：結論基于多年的蜜蜂研究，指出目前認為安全的殺蟲劑濃度對蜂群的生存仍可能產生巨大影響。

研究報告的作者、倫敦大學皇家霍洛威學院研究生哈里·西維特表示，盡管蜜蜂看上去簡單，但“它們的工作很艱難”。他說，為了有效地找到和收集食物帶回蜂巢，工蜂必須迅速學會識別（然后記住）最有效的覓食路線。最為重要的是，路線會隨著季節和其他因素的變化而變化。蜜蜂甚至記得最近采過哪些花，因此不會浪費時間再去一次。

這一切都需要良好的記憶力和學習能力——許多實驗室研究都通過“喙伸試驗”觀察到了這些特質。蜜蜂靠近香甜美味的花蜜時，就開始伸出舌頭。研究人員在實驗中將蜜蜂暴露于殺蟲劑之中，然后觀察它們在被促使覓食時的行為，看看它們什么時候或者是否還會伸出舌頭。西維特及其同事收集了其中23項研究數據，并對研究結果進行了大規模分析。

他們發現，蜜蜂在田間可能接觸到的相當劑量的殺蟲劑“對其學習和記憶產生了顯著的負面影響”。無論蜜蜂是突然接觸大量殺蟲劑還是長期少量接觸，情況都是如此。不管蜜蜂是暴露于新煙堿類殺蟲劑——一種自1990年代開始使用、如今監管日益嚴格的農藥——還是其他殺蟲劑之中，情況亦是如此。

現行的殺蟲劑管理條例旨在確保其使用濃度不至殺死蜜蜂，但這些目前合法的劑量顯然使工蜂變笨了，進而可能影響物種生存。西維特認為：“監管和政策應當轉向解決殺蟲劑的亞致死效應問題。”

這些發現間接提出了另一問題，即那些殺蟲劑如何影響研究尚淺的蜂類。圭爾夫大學科學家伊麗莎白·貝茨接受《科技新時代》采訪時稱，蜜蜂并不都是群居的。她表示：“許多野生蜜蜂并非群居，如果它們的學習或記憶受到影響，不會有其他同類伸出援手或收拾殘局。”

俄亥俄州立大學昆蟲學家里德·約翰遜在《科技新時代》電子郵件采訪中表示，問題在于：“在蜜蜂出沒地使用殺蟲劑能否保證它們的安全？”他寫道，某種意義上，這項研究具有23項研究的證據優勢，其“給出的答案是‘否”。

后續問題深入到我們最基本的需求之一——食物。殺蟲劑在大規模工業化農業中必不可少，蜜蜂一定程度暴露其中無法避免。那么，問題就在于蜜蜂能接受多大程度的傷害——約翰遜表示，監管迄今尚未解答這一問題。

與以往一樣，還需進行更多的研究。但渥太華大學蜜蜂保護學家杰里米·克爾告訴《科技新時代》，這項研究值得關注。他說，該研究的結論基于23項研究中100多個獨立實驗的證據，這讓他們的發現更有分量。他寫道：“研究給出的啟示是，蜜蜂接觸新煙堿類殺蟲劑后，會開始喪失學習和記憶的能力。”

他寫道，這份報告的價值在于表現出對這一問題“在知識層面達成的共識”。這一結果值得殺蟲劑政策制定者關注。貝茨說：“隨著全球對新煙堿類殺蟲劑的限制不斷增加，許多人將尋求替代化學品來保護農作物。”考慮這些化學物質可能對蜜蜂產生何種影響頗為重要。? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?□

（譯者為“《英語世界》杯”翻譯大賽獲獎選手;譯者單位：山東省文登整骨醫院）