Unintended Consequences II: a "safer" pesticide kills bees in new ways.

Beekeepers know that their hives are at risk when pesticides are sprayed anywhere nearby, and occasionally lose massive numbers of bees to unanticipated spray programs. But the problem seemed to be manageable even in the 1950's and 1960's when large scale use of highly toxic pesticides was at its peak.

Colony collapse disorder is a syndrome - a cluster of symptoms - not actually a single disease, so far as we know. In the last decade many beekeepers have discovered that their colonies suddenly drop in numbers to the point of collapse. Sometimes the dying bees are found, as in this amateur blogger's pictures. But it can be difficult to tell whether diseases, pesticides, or some other cause is responsible. What's clear is that there have been massive losses of honeybees for the last 10 years. This article has a chart showing that losses more than doubled in most parts of Canada in the last 5 years. This summer I bought honey from a farmer near Creemore, Ontario who was so discouraged he was thinking of getting out of beekeeping. He had lost 85% of his colonies last winter.

In my last blog I mentioned that a strange unintended consequence of large scale, industrial-level beekeeping may be serious harm to bumblebees. In this post, I want to talk about another unintended consequence of a well-intentioned change made by the pesticide industry about 20 years ago.

Nicotiana alata by Carl E. Lewis - CC 2.0

The "neonicotinoid" pesticides were created 20-30 years ago to reduce harms to birds and mammals from pesticides. The name means new-nicotine-like and is descriptive. Tobacco plants make nicotine not for your smoking pleasure but because it is toxic to insects. In fact 100 years ago tobacco extracts were sprayed on greenhouse plants as a natural pesticide.

Nicotine, and the neo-nicotinoid pesticides, bind to an important receptor in nerves. Insect nerves are more disrupted by this than nerves of mammals or birds, making these compounds fairly safe for you, your cat, or your budgie. As such they were a great advance over the older generations of pesticides.

We humans are rarely content with just some improvement; we want more and more. So the chemists modified neonicotinoids to be persistent (so a low dose would work longer) and soluble in water. This meant an even smaller amount could be applied as a coating on seeds and soaked up by the sprouting seedling. This meant no spraying, and even protection of all parts of the plant. As a result neo-nicotinoid pesticides are now the most popular and widely used commercial pest control substance, with billions of $$$ in sales each year.

treated corn seed

As a result, corn growers now find it almost impossible to buy commercial quantities of high-yielding corn varieties that are untreated. Almost all seed (99.8%) sold is treated with a combination of a fungicide and a neonicotinoid.

That's why the findings of a team led by Christian Krupke of Purdue University are so important. Prof. Krupke was called in when local beekeepers reported large bee die-offs around corn seeding time. Dead bees collected had measurable amounts of neonicotinoids. To determine if these could be a cause of death and how they might be getting into the bees, Krupke's team planted corn over two years using treated seeds and normal planting methods, as well as saved seed from the previous year (which was untreated).

Some of their results have been published online in the the journal PLoS One (available to anyone - click the link). They discovered that a lubricant used to keep the coated seeds from sticking to each other - talcum powder! - ended up highly contaminated with pesticides. The contaminated talc is blown away and ends up coating spring flowers and plants near the fields. This is the first way bees are exposed.

guttation drops, not dew

The second exposure comes when the corn seedlings are just up. Many plants exude small droplets of sap from leaf tips at night when the humidity is high, called "guttation drops". To you or me they look just like dew, but bees know that they are sweet and will collect them just like nectar first thing in the morning. It's been known for several years now that guttation drops from treated corn seeds are so toxic they kill bees in just hours. The risk to bees is highest in the first week after emergence.

The third point of exposure is one of the least expected. When corn "flowers", that is when the tassels mature, vast amounts of pollen is available. Beekeepers have observed for years that bees will avidly collect corn pollen. Krupke's team found that foragers bees from hives near fields of treated corn were bringing back large amounts of corn pollen with significant levels of neonicotinoids in it. This pollen goes to feed new larval bees and newly emerged nurse bees in the hive. Over the life of one young bee in the hive, she would consume an amount of pesticide equal to 1/2 of the lethal dose for bees. This might or might not be fatal, but Krupke et al's analysis of dead and dying bees found near their hives showed much higher levels of neonicotinoids than from healthy bees.

The fourth exposure method is not discussed much in their recent article. However in a talk I heard Krupke give at the North American Pollinator Protection Campaign (NAPPC) 2011 conference, he told us that his colleagues found significant amounts of neonicotinoids in soils that had not been exposed to treated seeds for 2 years. Some estimates suggest these compounds may have a half-life of 15 years or more in the soil. This means that in fields planted with treated seed for 3 years out of a typical 4 year crop rotation, the "steady-state" level of neonicotinoids in the soil could end up several times higher than what is put on in any year.

So there's bad news and there's good news. The bad news is that even when the corn is long gone, the same fields may be producing flowers contaminated with neonicotinoids. The good news is that some of the contamination can be removed by improving seeding techniques - control that talcum powder!

dead honeybees - Clement Kent, CC 2.0

As one person at the NAPPC conference pointed out, the simplest, least debatable step would be for the manufacturers of neonicotinoids to tweak their formulas so that the pesticides are less persistent. This would give them something new to patent and help protect the environment. We can only hope that Bayer, Monsanto, Syngenta, and Dow take this message to heart, before we have converted much of our agricultural landscape into a toxic mess that will last a generation.



Krupke, C.H., Hunt, G.J., Eitzer, B.D., Andino, G., and Given, K. (2012). Multiple Routes of Pesticide Exposure for Honey Bees Living Near Agricultural Fields. PLoS ONE 7, e29268.

Can you say "unintended consequences"?

Figure 2 from Core et al 2012

The unlovely creature at top left is a fly which parasitizes bumblebees in North America. In an article just published in the online journal PLoS One (accessible to anyone, follow the link) a group of researchers from San Francisco State University describe how this native parasitoid has recently jumped to honey bees.

Professor John Hafernik and his team found the larvae of this fly inside up to 10-15% of foraging worker bees in autumn. The fly larvae kill workers in about 7 days.Flies were found in samples from migratory bee colonies that travel over much of the US 48 states, so the problem is not restricted to California. Indeed moving the colonies may spread the fly.

Panel B shows the adult fly landing briefly on a bee and laying eggs - a process that takes only a few seconds. This seems to happen while the workers are collecting nectar and pollen.

After about a week, the 3-20 larvae feeding inside the worker have grown large. At this point infected workers abandon the hive, often at night, and fly away. They are attracted to lights where they seem disoriented and uncoordinated. Normal bees almost never fly at night. Up to 91% of the workers found at lights at night were infected with the flies.

Typically the next day the bee dies and some time later fly larvae crawl out of the bee (panel C) to pupate in the soil and later emerge as adults.

Hive abandonment is part of Colony Collapse Disorder, and this fly may be contributing to that syndrome. The researchers found that the adult flies may be carriers of several honeybee diseases, so may spread them from one hive to the next.


Although these flies are a native part of the large suite of parasites, parasitoids, and diseases which attack our native bumblebees, they pose a disturbing new threat to bumblbees. Why? Bumblebee colonies are much smaller than honeybee hives and are very small in spring and early summer, so the fly's native hosts are not as abundant. Flies may build up to much larger numbers by feeding on very numerous honeybees. The researchers showed the flies attack bumblebees and honeybees indiscriminately, so populations of native bumblebees may be diminished as an unintended consequence of keeping honeybees.

A further risk is that honeybees and to a smaller extent bumblebees are shipped between continents. If infected North American worker bees end up in regions where the fly is not native, damage could spread.

Because infected bees are uncoordinated, clumsy, and go out at night they have been dubbed "zombie bees". This may give some zombie movie fans a thrill, but this risk is a serious one because our pollinators are already at risk from pesticides, disease, and other parasites.

Core, A., Runckel, C., Ivers, J., Quock, C., Siapno, T., DeNault, S., Brown, B., DeRisi, J., Smith, C.D., and Hafernik, J. (2012). A New Threat to Honey Bees, the Parasitic Phorid Fly Apocephalus borealis. PLoS ONE 7, e29639.

Some links to while away your winter time with...

Wow - I have such a backlog of stuff to post here it's not funny at all! Just a few more days until I get the backlog of other stuff done and then I will post like mad...

In the meantime, here are three interesting links from around the world.

Colletes hederae - CC (1)

The first talks about a group of underground-nesting bees that line their tunnels with a mixture of silk and a previously unknown plastic. Better known as "plasterer bees", the genus Colletes has many members with varying lifestyles - but the bees this story is about have also been called "cellophane bees" and now "polyester bees". Makes you glad for the scientific name amidst all the confusion.

The second gives you a tour around the wildflower garden property of Christina Kobland in Pennsylvania. We don't all have 4 acres to play with but it's wonderful to see what can be done.

Birds killed by buildings. Copyright Kenneth Hardy

And the third is like the first - part of the growing trend to using bio-mimicry to make better, greener materials part of our lives. The researchers at Arnold Glas have figured out how to make a picture window that is transparent to you and me but looks like a spiderweb to a bird. Birds know to avoid flying through sticky webs and this helps prevent life-threatening collisions with windows.

Sentinels on the Wing: the Status and Conservation of Butterflies in Canada.

That's the title of a talk by Peter Hall, Research Associate at the Canadian National Collection of Insects, Ottawa, and co-author of The Butterflies of Canada. It will be presented on Saturday, November 19, 1:15 p.m. Room 110, Ramsay Wright Zoological Laboratories ( St. George Campus, University of Toronto, 25 Harbord Street, Toronto) with a reception to follow. Following the recent publication of Butterflies of Toronto, this is a great opportunity for Muddy York fans of some of our most beautiful pollinators to hear up to date information. Open to the Public.

You need an artist to bring the science back to the way we live, to a human scale.

That's a quote from artist David Buckland, founder of Cape Farewell, a group promoting a cultural response to climate change. Long based in England, Cape Farewell is opening its North American office in Toronto with a benefit concert on Thursday November 10.

Mormon Fritillary & Showy Fleabane - David Inouye 2009

hummingbird and alpine delphinium - D. Inouye

flies pollinate alpine flax - David Inouye 2009

Why am I noting Cape Farewell's efforts in a blog on pollinator gardens? Well, pollinators depend on flowers and flowering dates are changing because of climate change. At the recent North American Pollinator Protection Campaign meeting in Washington DC, I heard a short presentation on this issue by scientist David Inouye. He has been tracking wildflowers and their pollinators for 40 years in the Colorado Rockies. There are many different stories of individual pollinator-plant interactions, but one example given by Inouye in a 2009 talk deals with the flower Erigeron speciosus and the Mormon Fritillary butterfly Speyeria mormonia. The butterfly is an alpine species and depends on alpine wildflowers. Inouye  and Carol Boggs of Stanford University have shown that earlier snowmelt in the Rockies is reducing butterflies, because flower buds are emerging earlier when frosts are still a high risk. As a result there are fewer flowers. Inouye has shown this trend for several early-blooming alpine flowers whose populations are declining. The pictures shown here (all from the 2009 talk) illustrate some of the flowers and pollinators.

Simon Potts et al. 2009

These unexpected interactions aren't confined to the mountains.This chart from a research report by Simon Potts and colleagues shows how blooming time of blackcurrants in England (green circles) used to coincide with emergence dates of a key pollinator (red triangles) in the 1970's. Now the flowers bloom almost a month earlier than the bees emerge, reducing fruit set.

So, going back to Cape Farewell - climate change and pollinators turn out to have interesting and non-obvious overlaps. Explaining these to the public takes time, patience, and a gift for presentation that artists and media people have more than most scientists. That's why we as people interested in pollinators and their plants should be learning from Cape Farewell's example.

In another blog to be posted soon, I'll be asking you the readers about celebrities and pollinators.


- Clement Kent

p.s. find out more about Cape Farewell and the Horticultural Society Vegetable Garden tour in this post

Protecting Pollinators by Improving Water Quality? Read on..

Prof. M. Isabel Ramirez, 2011 Pollinator Advocate

Prof. Isabel Ramirez is the Mexico Pollinator Advocate for 2011. She is doing an ambitious project in the Morelia district of Mexico to help local people reforest their land. She's providing them with cheap tools to measure water quality and calibrating the tools with her own measurements. Why? Water quality is a "first victim" of deforestation and leads to increased illness in village children. If local people see that reforestation is making their children healthier, they have extra reasons to preserve the trees. Why is she a Pollinator Advocate? Guess who overwinters in forests in the Morelia district? If you guessed 3/4 of North America's monarch butterflies, you are golden! [Caveat: post based on my conversations with Prof. Ramirez; any mistakes my own]

 

Although I enjoyed meeting many people at the 2011 NAPPC (North American Pollinator Protection Campaign) meeting in Washington last week, it was a particular pleasure to meet the Mexican participants. Although the NAPPC is a 3 nation effort, the resources available to US participants typically dwarf those in the "also ran" nations of Mexico and Canada. So, it is very interesting to meet people from the "fringe" and understand how they are making progress on these critical issues.

I found Prof. Ramirez's approach, which takes into account many issues of everyday life for people living in Morelia, a very interesting model. In addition to the water quality issue, she is trying to build ownership of the forest resources by the local people. This makes them less likely to participate in clear-cuts (most of them illegal) perpetrated by outsiders who offer the local people a pittance to cut down their natural inheritance. There are many echos of land management issues in Native Canadian areas for the thoughtful to consider here.

Clement Kent (Canada) and Isabel Ramirez (Mexico)

 That's why I felt particularly honoured to be a NAPPC Pollinator Advocate: because of the company in which I found myself.

- Clement Kent, Pollinator Gardens Project of the Horticultural Societies of Parkdale and Toronto

 

A Review of Sweet Things at the Revue

photo by gak, rights reserved

The Revue Cinema has been in its west-end Toronto community for 100 years now. Today Bee Biologist Brock (known as BBB to friends) Harpur and I attended the Epicure's Revue, a monthly event featuring a film on food plus tastings provided by a number of local chefs and eateries.

Today's feature film was Colony, a documentary by Carter Gunn and Ross McDonnell about American beekeepers and their trials with colony collapse disorder. This is the mysterious problem which has caused honeybee colonies to simply pull up stakes and fly away into the sunset, to their beekeepers' distress.

The film does a good job of introducing some interesting characters in the beekeeping community and showing how the colony collapse combined with the 2008 economic collapse has been ruining their businesses. However, it takes a limited point of view heavily influenced by these large commercial "pollinators", as beekeepers whose main business is renting out their bees for crop pollination call themselves. The idea that being on a flatbed truck several months of the year, fed sugar water, and moved from Florida to California to Maine to Florida might be stressing the bees never came up. Beautiful visual filmwork and lots of human interest, but a partial failure through not exposing us to more sides of the problem.


No such caveats apply to the tastings before the show! BBB, who has a sensitive palate, thought highly of them while I positively wallowed in the lavender and honey ice cream from the Chocolateria and the chevre balls coated with nuts and honey from Lardon, just next to the cinema. For chocolate lovers, I should note that the Chocolateria has run some other wonderful events at the Revue.


Fred Davis, who keeps bees in several Toronto locations including atop the Canadian Opera Company's building, provided tastings of COC summer and fall honey, as well as Casa Loma honey and comb. He described beekeeping in Toronto at landmark sites and showed beekeepers gear. You can here more from Fred here.

Maria Kasstan and Seeds of Diversity. Courtesy of Toronto Beekeepers Coop

Fred is just one of over 60 members of the Toronto Beekeepers Co-op. There were other members at the Revue, including musician Maria Kasstan who was staffing a Seeds of Diversity booth, just as in the picture from last year. There's a great interview with Maria here. Maria is a member of the Raging Grannies, and I believe may have provided a song or two about pollinators at a recent event (but, I can't find a link. Help!).

All in all, a very sweet event!