The pesticide ban did not get rid of all neonics and there are many other problems that pollinators face; habitat destruction, bee dis- eases and a lack of food to name just a few. Nevertheless, the dis- covery of new biopesticides that are non-toxic to honeybees pro- vides hope for the future of pest control. But it is early days for these exiting new strategies and, for now, more simple efforts may improve the bleak situation of our pollinators in the short term. Falling bee numbers and rising food prices Like most other species, some plants have sex to reproduce. This process involves pollen grains – which are the plant’s male sex cells – being transferred to the female part of the plant. Honeybees, and other insects that eat nectar and50
food for thousands of other species, scientists have estimated that these insects pollinate around one third of the world’s crops, includ- ing; apples, onions, cauliflower, broccoli, coffee and cocoa (used to make chocolate).pollen, are an impor- Pollen grains Because they are kepttant part of this process. in hives, bee keep-They fly from plant to Mostly, honeybees are ers are able to keep aplant searching for nec- kept in hives and polli- detailed record of hon-tar and pollen. In doing nate our crops, but wild eybee numbers. Usingthis pollen sticks to the insects such as bumble- this and other honey-bee’s body and is trans- bees also contribute. As bee data from acrossferred between flowers. well as pollinating wild Europe, it is clear there flowers which provide has been a dramatic fall in honeybee numbers in the last 30 years, with the number of hives falling by about a quar- ter in this time (1). It also seems as if honey- bee numbers are falling much faster in the UK than in other European countries (2). 51
As well as affecting pears. Elsewhere in the would be needed to pol-the environment, the world crops like cocoa linate all of its crops.decline in bees could also and coffee, which rely This means that thereput a dent in the wallets on insect pollination, is an over reliance onof consumers. Professor would also be under wild pollinators such asDave Goulson, pollina- threat. This may then bumblebees and hover-tor expert based at the push up food prices, flies and this, in itself,University of Sussex, and reduce food pro- is dangerous becauseexplains: “The worst duction at a time when we don’t know exactlycase scenario would be the world’s population how many wild pollina-ending up without polli- is ever increasing.” tors there are. Goulsonnators or perhaps, more said: “The key problemrealistically, not enough A study released early is that we don’t reallypollinators to give us this year had a simi- have a reliable mea-a full yield. The fear is lar conclusion (3). It sure of wild bee num-that we will start seeing suggested that Europe bers at the moment.yield declines in crops had 13 million fewer For most pollinators welike raspberries, straw- honeybee colonies than don’t have much of aberries, apples and clue what is happening until they disappear.” This has worried sci- entists with some sug- gesting there may be a food security catastro- phe in the future if we don’t act to stop the fall in bee numbers (4). Bumblebee 52
The risk of neonics cells in the nervouson pollinators system, disrupting sig- nals being transmitted For years, scientists scientists paid special around the insect bodyhave been trying to attention to the effect (5). This is irreversiblefind out exactly why of this group of pesti- and eventually leadshoneybee numbers are cides on bees. to paralysis and death.continuing to decline Unfortunately, neonicsand it turns out that Neonics are usually are not specific to pestsbees face a number used as a seed dress- and they can also harmof problems. Intensive ing in agriculture. This bees too.farming practices have means seeds are coat-reduced the habitat in ed in the pesticide After completing doz-which bees can live, before being planted, ens of studies, it wasthere has also been a providing protection for found that neonicsdecrease in wild flower the crop before it has could kill bees at verynumbers meaning that even started growing. small doses. At small-bees are running out of As the seed grows the er doses still, it wasfood. Several diseas- pesticide coat is incor- found that the pesticidees, to which bees have porated in to the plant reduced honeybees’little resistance, have itself, giving it lifelong ability to navigate andalso been introduced. protection from pests. learn new information.Added to this, bees face Neonics work by affect- The research was com-a threat from several ing the brain and ner- pleted both in the lab,different types of pes- vous system of insects. and in the field makingticide, including those The active molecule it very convincing (6).containing neonics. binds to receptors onDuring their research, On the back of this research, the EU asked the European Food 53
Standards Agency to the ban was based. ics being used in gar-find out exactly how Nevertheless, the ban dens and parks. Thesedangerous neonics were was eventually passed spray-on pesticides areto bees. It was dis- with 15 countries voting still available in gar-covered that this group for it and eight against. den centres. On top ofof pesticides posed an It was then decided that, the ban also only“unacceptable risk” to the ban would last for applies to floweringhoneybee populations, two years, before being crops and crops plantedeventually leading to reviewed in 2015. in the spring or sum-the controversial ban of mer. Other crops, suchneonics in agriculture. However, even with as winter wheat, areBut this was not a simple the ban in place, bees not covered by the banprocess, the agrochem- will not enjoy a com- and can still be treatedical industry fought to pletely neonic-free with the restricted pes-oppose the ban and the environment. The ban ticide.UK government reject- did not affect neon-ed the science on which 54
Australian funnel-web spiderSpider-venom one day control pests without kill-biopesticide ing or harming pollinators (7). In the time since the ban was This research was completed bybrought in, there has been more Erich Nakasu and his colleagues atresearch into how neonics affect the University of Newcastle. Thebee health. There has also been team chose to focus on venom pro-some early research into alterna- duced by the Australian funnel webtive pesticides, called biopesticides, spider as a potential biopesticide aswhich are less harmful to pollina- it has previously been shown to betors. A paper, published recently in deadly to pest insects. They com-Proceedings of the Royal Society bined the toxic molecule taken fromBiology, detailed a new biopesticide the spider venom with a secondmade from spider venom that may “carrier” molecule. This allowed the spider venom to be delivered to the pest orally, by spraying on a crop 55
for example. Scientists exposed compared to current alternatives”.honeybees to the spider venommolecule at a range of concentra-tions, ranging from minute doses The exact reason why this newto doses so high that they would biopesticide is harmless to beesnever be seen in a field setting. and toxic to other pests is not com- pletely clear. But it seems to be related to the spider venom mole-After completing the research the cule’s effect on ion channels, whichteam found that the new biopesti- are proteins found in the lining ofcide did not pose a significant risk all cells. These proteins control theto honeybee health. In fact, the flow of charged ions in and out ofspider venom molecule was about the cell, and are vital for manyas harmless to honeybees as a non- important physiological processes.toxic control substance, Nakasu It appears that the spider venomsaid: “The fact it can selectively kill molecule targets and inhibits ainsect pests, but not bees, was actu- particular type of ion channel inally surprising”, he went on to say: the cells of the pest insect, caus-“we consider the molecule to be ing mortality. This process doesn’trelatively safe to bees, particular- seem to happen in honeybees andly when this may be because they have a slightly different version of the ion channel found in pest species. This different type of ion chan- nel may not be susceptible to the new biopesticide did the spider venom molecule,not pose a significant risk making honeybees resistant to the molecule. The lab to honeybee health group at the University of Newcastle is currently com- pleting research to confirm this theory. 56
The results of thestudy are no doubtexciting for the futureof pest control, Nakasusaid: “There is a clearand pressing need foralternative pesticides.Studies like ours arevery important becausethey show that thesetoxins provide analternative that doesnot have a measur-able impact on bees atfield-relevant doses inassays that are verysensitive.” But it is important to ticide will have to go molecule doesn’t dam-note that this is the through the licensing age the environment.very first stage in bring- and registration pro-ing a new biopesticide cess. Field trials willto the market. Nakasu also take place to makesaid it could still be sure the spider venomfive to 10 years beforespider venom biopesti-cide becomes availableto farmers. During thistime the new biopes- 57
pointed, that an alter- native to the banned neonics may not even be necessary, he said: “I have been trying to flag up for some time now that there is no clear evidence as to what difference to yields neonics make, which is quite surpris- ing considering every- body uses them. If you were to take away the seed dressing and do everything else the same, there is no data to say how this would affect yields because no one has done this simple trial in the UK.”Do neonics For this reason, the But there have been areally help spider venom biopes- few trials in the US andcrop growth? ticide should not be they show that neonic seen as an alternative pesticides are coming to neonicinoid pesti- up short. A two year cides. Goulson also study on soybeans in South Dakota found no 58
yield benefits from neonic seed So why do farmers pay for anddressing because the pesticide con- use pesticides that may not be nec-centration was not high enough to essary in some cases? Accordingkill pests (8). These conclusions to Goulson farmers receive mostare hotly contested by the agro- of their advice from agronomistschemical industry who says that employed by the agrochemi-over time neonics do provide yield cal industry, he went on to say:benefits. Experts have suggested “Farmers do not have any source ofthat neonics should only be applied good data, so they rely on advice.if there is high “pest pressure” on It seems quite likely that they havethe crop. For example, there would been using something that theybe little point in applying a pesti- probably didn’t really need”.cide in an area with no pests. 59
You might think that we will have both in the lab and the field. It is fora better idea of how neonic appli- these reasons that many research-cation affects yields after the two ers are calling for the neonic ban toyear ban, but this is unlikely. Some be extended beyond 2015, when itof this year’s crops were treated is due to be reviewed.with neonics before the ban cameinto action. This means neon- Short-termics will persist in the environment strategiesuntil the crops are harvested. Thisonly leaves one year during which Biopesticides, which are non-toxicthe pesticide restrictions will be to bees, are still decades away.fully observed (before they are And in the meantime bees will stillreviewed in 2015), which may not be exposed to neonics – albeit to abe long enough to properly gauge lesser extent for as long as the banthe effect of the ban on crop yields lasts. On top of this, other pesti-and pollinator health. cides, bee diseases and a lack of pollinating flowers also pose a risk It is also important to note that, to bees. The current situation mayeven with the neonic ban, crops seem bleak for our pollinators butare still being sprayed with other there are things we can do rightpesticides. So they are not open to now to improve the health of bees.attack by pests in the absence ofneonics. Added to this, the evidence Goulson suggested that there arefor the negative effect of neonics many strategies that could improveon pollinator health seems to befar stronger than the evidence forthe positive effect of the same pes-ticide on crop yields. This can beseen in the numerous publicationsthat show how neonics harm bees60
the health of bees in the short term. raise awareness to try and improveFirst we must address the loss of pollinator health.habitat suitable for pollinators byplanting more flowers in gardens These strategies are still only inand parks as well as on farmland – their infancy. Goulson said: “Thethis will provide bees with food and initiatives under way that are tryingplaces to live. There should also be to get people to grow more flowersefforts made to reduce pesticide use are a bit of a drop in the ocean atin gardens, where neonics can still the moment, but if they gatheredbe used freely. Organizations such momentum they could make a realas the Bumblebee Conservation difference.”Trust promote these efforts andReferences:1)sciencedirect.com/science/article/pii/S01695347100003642)ibra.org.uk/articles/European-honey-bee-declines/3)plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.00829964)theguardian.com/environment/2014/jan/08/uk-food-security-honeybees5) ncbi.nlm.nih.gov/pubmed/116981016) ncbi.nlm.nih.gov/pmc/articles/PMC3338325/7)rspb.royalsocietypublishing.org/content/281/1787/20140619.full8)ricehoppers.net/wp-content/uploads/2013/05/Science-2013-Stokstad-675.pdf 61
“Why move through the oceans, if the oceans can movethrough you?” - Boyan Slat FREE SUBSCRIPTION www . ispectrummagazine . c o m 62
Search
