Bee Brave - Survival in the Face of Chemical Onslaught

Megachile xylocopoides     S.Reeve

 I remember the honeybees of my childhood, they were so numerous they were deafening. Now, I go out into the yard, and I see one, maybe two, on a plant (Eriogonum fasciculatum) that, a few years ago, had hundreds. But people forget, and many, younger than me, think this dearth is normal.  Back when I was a kid I marvelled at nature and found it everywhere: salamanders under every rock, bees crowding the flowering plants fighting for access to pollen and nectar, pollywogs in any puddle of water big enough for a frog butt, and this was normal-- even in a San Francisco subdivision. There is a new quiet normal and I feel sad for anyone too young to have experienced the bounty of my youth. In this article I have attempted to read and synthesize the latest scientific literature concerning the relationship between honeybee decline and the use of systemic neonicotinoid pesticides. 

Apis mellifera      S.Reeve

     I have looked at the issue of disappearing honeybees for years. I read everything I see concerning this issue. It is not just honeybees that are dying, pollinators have declined precipitously in the last twenty years. Monarch butterflies in the U.S. numbered one billion in the 90s and are now around 33 million, a decrease of 90% (Xerces Society). Native bumblebee populations have fallen. Several, once common species, are now rare or presumed extinct (Xerces Society) (1). Population decline has affected at least one fifth of U.S. bumblebee species, with some species close to extinction, and their ranges have shrunk (2). According to Sydney Cameron, an Entomologist at University of Illinois, Urbana-Champaign, “There are whole regions where we can’t find them anymore.” There are many reasons for the alarming decline of pollinators: loss of habitat, introduced disease, climate change, and pesticide use (Xerces Society).

                   Figure 1 Western Monarch Count 1997-2009 Xerces Society

      Honeybees are also dying.  Since 2006, the USDA estimates that 10 million honey bee hives have failed. Many scientists blame neonicotinoids for the disappearance of nearly a quarter of the honeybee colonies over the winter of 2013 in a phenomenon termed “Colony Collapse Disorder” or CCD. Neonicotinoids are a class of systemic pesticides, and the most widely used insecticdes in the world (3). Colony Collapse Disorder began to be a problem in 2004 when neonicotinoids started to become widely used as a prophylactic seed treatment for corn (Figure2). Currently, corn is planted on 84 million acres and constitutes the largest crop in the US (EPA). Since 2004, nearly all major agricultural crops receive neonicotinoid seed treatments increasing treated acreage to approximately 275 million acres. This is a lot of chemical when you consider that every single corn kernel planted has a coating of 1.25 milligrams of neonicotinoid pesticide which has the potential to kill over 100,000 bees (3). Corn kernels are also coated with numerous fungicides too (13). 

Figure 2 Dr. Susan Kegley Pesticide Research Inst.

     And while neonicotinoids are especially toxic to arthropods, they kill birds too. Cynthia Palmer, co-authored a report that found a tiny grain of coated wheat can kill a songbird (6) An especially troubling aspect of widespread seed treatment found no crop increase as a result, and insignificant benefit according to a recent scientific literature review (3). In total,140 different crops are treated with neonicotinoids, and hundreds of millions of acres of agricultural lands, gardens, golf courses , parks, homes, and lawns are treated with neonicotinoids every year. Frequently used flea and tick treatments for pets also contain these pesticides. Neonicotinoids are a class of systemic insecticides with high toxicity to insects through neurotoxicity(3,5,7,13,15). They work by preferentially binding to nicotinoic acetylcholine receptors in the nervous system of insects and cause stimulation, receptor blockage, paralysis, and death. When the neonicotinoid binds the receptors never close and are thought to be irreversibly harmed  leading to excitation and eventually to death of the receptor, and when enough receptors are harmed --death of the bee. 

     The effects are cumulative, and bees are exposed in multiple ways throughout the growing season, from seed treatment dust, to pollen and nectar, and through accumulation in the hive (2,3,5,8). Remember, too, that crops are treated with multiple pesticides, fungicides, and herbicides which are collected in the hive (11,12). An nationwide analysis of 887 hive waxes and pollens found 121 different pesticides (12). Almost 60% had a neonicotinoid, occurring at up to 99 ppm (with sublethal effects at 5-10 ppb) (12). Close to 50% of the samples had multiple pesticides, acaricides, herbicides, or fungicides (11,12). Toxic load of multiple pesticides have additive and synergistically negative effects on honey bee health (10, 11). So it is no mystery why bees and other organisms are dying, in fact, it is almost a wonder that ANY exist with this chemical onslaught. 
     Neonicotinoids have sublethal effects at remarkably small doses of ≥0.5ng/bee (clothianidin) and ≥1.5ng/bee (imidacloprid) (3,5,7). Multiple exposures of 20+ppb cause death, and one dose of approximately 142ppb is the acute lethal toxicity (15). To put it another way, a bee weighs 1/10th of a gram and the median lethal dose or LD 50 of Clothiandin, a neonicotinoid, is only 3 billionths of a gram (13,14). Compared to DDT, Imidacloprid, a neonicotinoid, is 10,000 times more toxic (3). If you wanted to kill honeybees, Clothiandin is what you would use. It is one of the most toxic chemical formulations for honeybees in existence(13).

     Multiple exposures from environmental sources and hive-stored pesticides increase behavioral problems in bees (3,5,7,13).  In tiny doses, neonicotinoids disturb bee navigation and memory, slow foraging behavior, and compromise social interactions, and communication (5,7,8,10). Reduced fecundity, and depressed immune systems are also implicated in neonicotinoid use (9). Increasing the dosage keeps bees from finding their way back to the hive which results in the characteristic symptom of CCD which is the absence of adult bees in the hive, and live brood and queen still present . There are currently 150 products approved for home and garden use that contain neonicotinoids, and over 465 products  registered (Washington State Extension). 

     Neonicotinoids are systemic pesticides, that are water-soluble, and persistent  in the environment (3,4,13,14). Because they are water soluble and systemic, they are readily taken up by plants through the vascular system (3). Soil or foliage treatments are both successful at spreading the pesticide throughout the plant, and become accessible to bees and other pollinators through nectar, pollen and guttation drops (13, 15). One study, by Penn State Entomologist, Dr. David Biddinger, found measurable amounts of residues in woody plants up to six years after application (15). He also found that chemical residues left in the soil from a previous year can be absorbed by untreated plants (15). Neonicotinoids contaminate surface water, ground water, and soil, endangering not only pollinators, but also other beneficial species that inhabit these ecosystems (4). Mayfly nymphs, for example, the bottom of the aquatic food chain and an important food source for many organisms, are killed at only one part per billion of neonicotinoids (3). One study of 136 wetlands, found as many as 91% had measurable levels of neonicotinoids, with a mean concentration of 91.7ng/L, and a high 3110ng/L or three times the level required to kill mayfly nymphs (4). Combine this with the fact that these chemicals bioaccumulate in environmental systems and have a half-life of up to three years it is easy to see the environmental damage they are causing (3, 13,15).  Over 90 percent of neonicotinoids turn up in water and soil affecting large numbers of target and nontarget organisms, and creating widespread environmental injury (3,4,). 

     Sales of neonicotinoids are a multi-billion dollar business with profits reaching 2.6 billion dollars a year (3). Pesticide companies are interested in maintaining this income stream and use many tactics to direct the attention away from neonicotinoids.

 http://ecowatch.com/2014/04/28/pr-tricks-pesticide-companies/

Tactics include: diverting attention away from neonics, blaming farmers and beekeepers, manufacturing doubt, targeting children, and spinning science. This works. Even with all of the environmental damage the United States has failed to take any regulatory measures against the use of neonicotinoids. Changes are being made on the local level, as Eugene, OR has become the first city to outlaw their use. We can only hope for the sake of affected organisms on land, in the air, and in the water, that many other communities will follow suit.

References:

1) Cameron, S.A., J.D. Lozior, J.P. Strange, J.B. Koch, N. Cordes, L.F. Solter, and T.L. Griswold.  2011.  Patterns of widespread decline in North American bumble bees.  Proceedings of the National Academy of Sciences 108:662-667.

2) Williams, N., 2003. Plight of the bumblebee. Current Biology 13, R463.

3) Goulson, D. (2013) An overview of the environmental risks posed by neonicotinoid insecticides. Journal of Applied Ecology, 50, 977–987.

4) Main AR, Headley JV, Peru KM, Michel NL, Cessna AJ, Morrisey CA (2014) Widespread use and frequent detection of neonicotinoid insecticides in wetlands of Canada’s Prairie Pothole Region. PLoS ONE 9:e92821

5) Yang,E.C.,Y.C.Chuang,Y.L.Chen,andL.H.Chang. 2008.Abnormal foraging behavior induced by sublethal dosage of imidacloprid in the honey bee (Hymenoptera: Apidae). J. Econ. Entomol. 101: 1743Ð1748.

6) Mineau, P., Palmer, C. 2013. The impact of the nation’s most widely used insecticides on birds.

7) Schneider, C. W.; Tautz, J.; Grünewald, B.; Fuchs, S. RFID tracking of sublethal effects of two neonicotinoid insecticides on the foraging behavior of Apis mellifera. PLoS ONE 2012, 7, e30023.

8) Henry, M., Beguin, M., Requier, F., Rollin, O., Odoux, J.-F., Aupinel, P. et al. (2012) A common pesticide decreases foraging success and survival in honeybees. Science, 336, 350–351.

9) Gill, R.J., Ramos-Rodriguez, O. & Raine, N.E. (2012) Combined pesticide exposure severely affects individual and colony-level traits in bees. Nature, 491, 105–119. doi: 10.1038/nature11585.

10) Wu, J.Y.; Anelli, C.M.; Sheppard, W.S. Sub-Lethal effects of pesticides residues in brood comb on worker honey bee (Apis mellifera) development and longevity. PLoS One 2011, 6, e14720.

11) Johnson R.M., Ellis M.D., Mullin C.A., Frazier M. (2010) Pesticides and honey bee toxicity – U.S.A., Apidologie 41, 312–331.

12) Mullin, C. A., M. Frazier, J. L. Frazier, S. Ashcraft, R. Simonds,D.vanEngelsdorp,andJ.S.Pettis. 2010. Highlevels of miticides and agrochemicals in North American apiaries: implications for honey bee health. PloS ONE 5: e9754.

13) Krupke, C.H., Hunt, G.J., Eitzer, B.D., Andino, G. & Given, K. (2012) Multiple routes of pesticide exposure for honey bees living near agricultural fields. PLoS One, 7, e29268.

14) EPA (United States Environmental Protection Agency).  2003  Pesticide Fact Sheet: Clothianidin.

15) Hopwood J, Vaughan M, Shepherd M, Biddinger D, Mader E, Hoffman Black S, Mazzacano C (2012) Are neonicotinoids killing bees? http://www.xerces.org/neonicotinoids-and-bees/. Accessed June 2014

Local Hero in Habitat Restoration - Arne Johanson

Today I had the pleasure to visit the site of an ongoing habitat restoration. Since 2004, Arne Johanson and a handful of volunteers has painstakingly and lovingly tipped the balance from invasive weeds to native plants on nearly 1000 acres of the Artesian Creek watershed in San Diego County. Arne uses a recruitment technique, called the Bradley Method, developed by two sisters from Australia.  The method is remarkable for its logic and cost effectiveness. Traditional habitat restoration entails killing weeds and then planting or seeding native plants. Without constant vigilance areas such as these are quickly overtaken by a new crop of non-native weeds. The irrigation, and costs for plants, plus labor, is often prohibitive. Not to mention, the plants or seeds used are often from different localities not as suited for  the unique conditions of the site they are planted.

Restored Area of Artesian Creek

Arne has perfected his technique which relies on the recruitment of native propagules that naturally move in once the biomass of invasive weeds is reduced. He is strategic, and prioritizes weed removal to areas that have established populations of native plants, so seeds of the native plants are able to move in and fill in the vacuum created by weeding. While it may appear that wholesale removal of a large area of weeds in a short amount of time is an effective method to revegetate acreage, but the weedless expense is quickly reengulfed if native plant communities are not close by. The Bradley Method relies on the power of Mother Nature to heal a disturbed landscape with a little nudge from Arne and his band of volunteers. A guiding principle for this type of restoration is never to weed an area larger than can be recolonized by neighboring native plants. Arne and his team accomplish all this on a tiny annual budget of $500-$1000. He has expanded his efforts to include Black Mountain, Lusardi County Park, Rattlesnake Canyon, and Poway Lake.
Ask Arne why he fights the good fight, and he will tell you, "It needs doing, and I can do it" it's his short answer to the philosophical question. The long answer is his heart felt joy upon seeing animals recolonizing an area, or seeing a new field of wildflowers, where there once was weeds. He says he will continue to wage this war,  "as long there are people able to keep at it."
Arne as a true hero! After many years of hard work he was recently nominated as a finalist for the Cox Conserves Heroes award. Let's hope he wins! Good job Arne and keep up the unbelievable work you do!

Rough Geographic Area of Arne's Restoration 

We botanized as we appreciated all that Arne and his team have accomplished. I attempted to write down most of the plants we saw, and here are some of the highlights:

Eriophyllum confertiflorum

Cneoridium dumosum

Scrophularia californica

Calochortus splendens

Malacothamnus fasciculatus

Antirrhinum nuttallianum

Dudleya pulverulenta

Mimulus aurantiacus (could be variety puniceus)

Plant it for the Bees: Ceanothus 'Ray Hartman'

Ceanothus 'Ray Hartman' is one of our most reliable, and garden adaptable, native shrubs/trees. This cultivar, is a blending of the coastal, Ceanothus griseus and the Catalina Island tree, Ceanothus arboreus. Developed in the late 1940s it has become a well known and dependable performer in the California coastal garden. Ceanothus griseus gives the leaves of the tree revolute leaf margins and bluer flowers than C. arboreus alone. This vigorous and fast-growing plant can attain 10 feet in a couple of years in my experience, and can

top out at about 20 feet tall and almost as wide. The buds will fool you because they are pinkish, but open to medium blue, large clusters of small flowers, that make you say, "ahhh."A large mature tree in full bloom is a sight to behold, and it will have you calling up local nurseries scrambling to find Ray, otherwise known as, "Mister Dependable." The reason it is an old, widely planted, and commonly occurring ceanothus or California lilac is because Ceanothus 'Ray Hartman' will not "up-and-die" in typical garden watering regimes like other species of Ceanothus are known to do.

Remember, Ceanothus are pioneer plants, and survivors, and for the most part cannot tolerate watering that doesn't resemble the precipitation rates of their native habitats. Ceanothus 'Ray Hartman' seems to be a bit of an exception to this rule--especially--when it is newly planted. It will gladly accept most watering and reward you with luxuriant growth. The fast growth comes at a price, however, and causes problems like shorter life span, wind throw, and the aborted development of strains of the symbiotic filamentous bacteria, Frankia. Ceanothus sp. are actinorhizal plants that fix nitrogen with the help of root-forming nodules of Frankia, much like the more familiar legumes and rhizobium bacteria.

Strains of Frankia are widespread and persistent in California soils even without the host plants being present. They are also important in many other ecosystems where nitrogen is limited. Pioneer plants are important to fix nitrogen, so that other plants can get established in depleted soils. In Southern California, frequent fires deplete nitrogen and Frankia are important to hasten the reestablishment of populations of plants. Studies in southern California have identified 12 distinct strains of Frankia. Climate, geographic location, soil pH, and host species present are all thought to influence the identity of Frankia strains in a given area. Birds and water are known dispersers of Frankia. The bacteria also form relationships with other pioneer plants in the Genera: Alnus, Rhamnus (Frangula), and Eleagnus.  Unfortunately, when Ceanothus are pampered, Frankia have low levels of nodulation, this was shown in several greenhouse experiments that failed to yield the high rates of the sought-after intercellular infection of Ceanothus roots.

High Frankia infection rates improve growth, foliar nitrogen, and survival rates of Ceanothus. Because of this, it may be best to give Ray a little tough love and don't pamper him too much. Ceanothus have a undeserved reputation for being short-lived. Ceanothus tend to live longer and don't flame out at a young age when their irrigation rates are tempered.

While trees in full bloom are the stuff of dreams for humans, bees share that enthusiasm. To see a tree in bloom is to hear the excited buzzing of many bees gorging themselves on the bounty found in the little tiny flowers. Ceanothus are hands-down among the most favored bee plants in the California garden. I grow them as much for the anticipated hum of bees, as for the beauty of the blue corona of flowers. Non-native honeybees, as well as, native bumblebees, and native Halictid bees are big fans, and come from far and wide for an opportunity to partake. In the words of UC Berkeley urban bee entomologist, Dr Gordon Frankie, "Bees adore this plant!" Flowering Ceanothus are excellent and important pollen sources for bees. In my garden I consider it my duty, as well as, my pleasure to provide the finest that nature has to offer for my pollinators--especially for my bees. Ceanothus species do so many things well: they provide ravishing beauty, exceptional pollen for bees, and the fruit feed many species of birds. Plant Ceanothus and instantly attract wildlife that make your garden so much more than just pretty plants!

Lets Do This!

We live in Southern California. Few places possess the biological richness of our home. More species live here in San Diego County than just about anywhere in the United States. We are so lucky! One way we can help protect the large number of unique species is to landscape our homes with native plants. Think about it. Millions of years have honed the relationships between the endemic flora and fauna to the perfection that exists today.

But look around - what plants do you commonly see in your community? That's right, just a small number of exotic plant species from the big box store exist in nearly everyone's landscapes. The nectar from that tropical hibiscus or rosemary is not nearly as nutritious for local hummingbirds and bees as is the nectar produced by natively occurring Salvia mellifera or Phacelia campanularia. Local plants offer optimal nutrition for local fauna. Not only that, but exotic species are often poisonous to our fauna. For example, Nandina berries, although eaten by local birds, may kill them if consumed to excess. An opposite example of this is between our native Aesculus californica and honeybees--an exclusive diet of pollen and nectar from this plant will kill or disfigure the progeny of the honeybee. Honeybees are not from San Diego they originated in Europe and did not evolve to partake of our native Bottlebrush. Lets give our local fauna the local plants that offer them the chance to thrive.

Salvia mellifera

But, you say, my Pyracantha has fruit that the birds relish. That may be true, but recent studies show that not only is the nutrition superior in local plants, but the phenology or timing of the plants makes all the difference to the reproductive success of the creatures that evolved to eat the plants. Meaning that, even though a species of bird will consume fruit from non-native plant species their reproductive fitness is decreased just enough to negatively affect the birth rate. Both the timing of the crop and the nutrition of non-natives are inferior to the native species.

Phacelia campanularia

So we have the excellent nutrition native plants provide, plus native endemic plants are drought tolerant. In San Diego we typically get less than a foot of rain a year, and all of it in the months of winter and spring. Native plants have evolved adaptations to be able to survive on little water in the colder months and no water in the summer. Better yet, using locally sourced native plants fine tunes the drought tolerance to the same conditions as exist in your garden at home.

Aesculus californica

The biological richness of San Diego County means we have a large number of species of plants to chose from. And the great thing is these plants are gorgeous and occur nowhere else in the world! So lets do this! Lets plant natives, lets bring back the waning populations of birds, butterflies, and bees. We have the power to keep San Diego biologically rich and diverse.