Pesticides Are Making Bees Dumber杀虫剂让蜜蜂变笨了

凯特·埃施纳

Even if they survive， they might not thrive.雖可存活，恐难繁衍。

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.

说起蜜蜂与大黄蜂，你可能会联想到它们可爱而毛茸茸的身体及其对花朵看似漫无目的的喜爱。然而，它们黄黑相间（大多如此）的条纹之下却有着令人难以置信的头脑。一项新研究收集了23项有关蜜蜂和大黄蜂研究的证据：结论基于多年的蜜蜂研究，指出目前认为安全的杀虫剂浓度对蜂群的生存仍可能产生巨大影响。

研究报告的作者、伦敦大学皇家霍洛威学院研究生哈里·西维特表示，尽管蜜蜂看上去简单，但“它们的工作很艰难”。他说，为了有效地找到和收集食物带回蜂巢，工蜂必须迅速学会识别（然后记住）最有效的觅食路线。最为重要的是，路线会随着季节和其他因素的变化而变化。蜜蜂甚至记得最近采过哪些花，因此不会浪费时间再去一次。

这一切都需要良好的记忆力和学习能力——许多实验室研究都通过“喙伸试验”观察到了这些特质。蜜蜂靠近香甜美味的花蜜时，就开始伸出舌头。研究人员在实验中将蜜蜂暴露于杀虫剂之中，然后观察它们在被促使觅食时的行为，看看它们什么时候或者是否还會伸出舌头。西维特及其同事收集了其中23项研究数据，并对研究结果进行了大规模分析。

他们发现，蜜蜂在田间可能接触到的相当剂量的杀虫剂“对其学习和记忆产生了显著的负面影响”。无论蜜蜂是突然接触大量杀虫剂还是长期少量接触，情况都是如此。不管蜜蜂是暴露于新烟碱类杀虫剂——一种自1990年代开始使用、如今监管日益严格的农药——还是其他杀虫剂之中，情况亦是如此。

现行的杀虫剂管理条例旨在确保其使用浓度不至杀死蜜蜂，但这些目前合法的剂量显然使工蜂变笨了，进而可能影响物种生存。西维特认为：“监管和政策应当转向解决杀虫剂的亚致死效应问题。”

这些发现间接提出了另一问题，即那些杀虫剂如何影响研究尚浅的蜂类。圭尔夫大学科学家伊丽莎白·贝茨接受《科技新时代》采访时称，蜜蜂并不都是群居的。她表示：“许多野生蜜蜂并非群居，如果它们的学习或记忆受到影响，不会有其他同类伸出援手或收拾残局。”

俄亥俄州立大学昆虫学家里德·约翰逊在《科技新时代》电子邮件采访中表示，问题在于：“在蜜蜂出没地使用杀虫剂能否保证它们的安全？”他写道，某种意义上，这项研究具有23项研究的证据优势，其“给出的答案是‘否”。

后续问题深入到我们最基本的需求之一——食物。杀虫剂在大规模工业化农业中必不可少，蜜蜂一定程度暴露其中无法避免。那么，问题就在于蜜蜂能接受多大程度的伤害——约翰逊表示，监管迄今尚未解答这一问题。

与以往一样，还需进行更多的研究。但渥太华大学蜜蜂保护学家杰里米·克尔告诉《科技新时代》，这项研究值得关注。他说，该研究的结论基于23项研究中100多个独立实验的证据，这让他们的发现更有分量。他写道：“研究给出的启示是，蜜蜂接触新烟碱类杀虫剂后，会开始丧失学习和记忆的能力。”

他写道，这份报告的价值在于表现出对这一问题“在知识层面达成的共识”。这一结果值得杀虫剂政策制定者关注。贝茨说：“随着全球对新烟碱类杀虫剂的限制不断增加，许多人将寻求替代化学品来保护农作物。”考虑这些化学物质可能对蜜蜂产生何种影响颇为重要。                                   □

（译者为“《英语世界》杯”翻译大赛获奖选手;译者单位：山东省文登整骨医院）