Pollinator Presence Plummets

National Wildlife Week in Canada was from 6-12 April and this year’s theme was pollinators. Hot on its heels was National Pollinator Week in Washington D.C. from 22-28 June. I am pleased to see an upkeep of the pollinator profile. This is hardly surprising given the importance of these industrious workers. Their increasing decline makes profile lifters such as these of the utmost importance.

Birds, bees, bats, moths, butterflies, wasps, flies, beetles, midges, thrips and ants are all pollinators. Would you believe that 40 of Haagen-Dazs’ ice cream flavours depend on pollinators (Hulka and Van Arsdall, unda)? In Canada’s online magazine, EnviroZine, we are informed of another fascinating fact; ‘one in every three bites of food we eat – from fruits, berries, vegetables, nuts and seeds - is the result of pollination’. The information to follow in the article ‘Celebrate Pollinators This Spring’, is therefore even more worrying: ‘worldwide declines in pollinator populations’. Pollinator decline not only has an affect on our food supply, but also complementary and alternative medicine (Cooper, 2007).

One reason for this decline has been attributed to the use of insecticides and herbicides, which affect the pollinators themselves, their food sources and habitats. Interestingly, we are told in the EnviroZine article, that worldwide attention to pollinator conservation is in part thanks to Canadian blueberry growers. DDT was used for the control of spruce budworm in the forestry industry, but was replaced by fenitrothion in 1969. Unfortunately, this insecticide killed off the pollinators and caused blueberry production in New Brunswick, parts of Quebec and Ontario, to enter a decline. The forestry industry was taken to court by the blueberry growers, resulting in a change in forest spray policies.

Diseases and parasites are also contributing factors to pollinator decline. Maladies such as these are well-documented for honeybees, given their importance to apiculture. Parasites of the Western honeybee, Apis mellifera, include the parasitic mite, Varroa destructor; and the microsporidia, Nosema apis and Nosema ceranae. V. destructor is an ectoparasitic mite of a broad range of honey bees and attacks all lifecycle stages (ISSG, 2005). For more information on varroa mite, see CABI’s up and coming Invasive Species Compendium. N. apis and N. ceranae cause nosemosis in honeybees, where the parasitic protozoa invade and destroy cells in a bee’s gut. For more information click here.

Parasites and diseases have been implicated as possible causal agents of colony collapse disorder (CCD), a phenomenon that has caused 50-90% loss of honeybee colonies in USA beekeeping operations (Cox-Foster et al., 2007). CCD, also know as disappearing disease (Bonmatin et al., 2007), is when colonies suffer a rapid decline of adult bees (Glinski and Kostro, 2007) – literally the colony is abandoned and the bees are never found (Lean and Shawcross, 2007).

Other possible culprits of CCD include: contamination of pollen and nectar by insecticides such as imidacloprid and fipronil (Bonmatin et al., 2007); Israeli acute paralysis virus (Cox-Foster et al., 2007); a fungus, bacterium, virus, toxin or ‘other stresses’ (Osborne, 2007); genetically modified crops, lack of genetic diversity and lineage of bees, immunosuppression (Glinski and Kostro, 2007); changed cultural practices, cool brood (Oldroyd, 2007); hive beetles (Vanengelsdorp et al., 2007); lack of food and electromagnetic radiation (Kievits, 2007). Eastbourne certainly made efforts to look after it’s local bee population last year when permission to erect a mobile telephone mast was rejected, after fears that radiation may be causing bee decline (Lean and Shawcross, 2007). It would appear that no single factor is responsible for CCD or honeybee decline in general (Frazier et al., 2008).

Land development leading to habitat loss and landscape fragmentation, plays a part in declining numbers of pollinators. Availability of food resources and nesting sites are reduced. Intensive farming has led to homogeny in the landscape and loss of wildflowers, but while this change has affected most bumblebee species, for example, it has not affected them all (Dicks, 2004).

The length of bumblebee tongues has been offered as an explanation for decreasing numbers, because almost all the bumblebee species in decline have long tongues and like flowers with long tubes of petals (clover, vetch, knapweed, thistle), found in traditional hay meadows – also in decline. The key here is ‘almost all’, for there are those species that do not fit this pattern and lead us to question other factors of bumblebee life history. Little is known about bumblebee ecology and key questions, which would help in a bee conservation effort, remain unanswered (Dicks, 2004).

To counteract plummeting numbers, perhaps we should follow the City of Guelph’s lead by developing unwanted areas into havens for pollinators. It is hoped that the world’s first pollinator park in Canada will be positioned on a 40 hectare landfill site, containing forbs, grasses, asters, daisies, and habitat varying from dead wood to sandy soil to rocky piles (Harries, unda).

Closer to home, its easy to encourage pollinators by leaving an area of your garden/allotment to go wild and remain pesticide free. This will encourage habitat diversity and corridors for pollinator movement and survival.

If you want to see the ‘big six’ * (British Isle bumblebees that is), Lynn Dicks (2004) points us in the direction of the following bumblebee-friendly areas: Salisbury Plain; The Somerset and Gwent Levels; The Essex and Kent Thames corridor; The Outer Hebrides; and Castlemartin, Pembrokeshire.

*The ‘big six’ British Isle bumblebees are: the common carder bee (Bombus pascuorum); the red-tailed bumblebee (Bombus lapidarius); the buff-tailed bumblebee (Bombus terrestris); the white-tailed bumblebee (Bombus lucorum); the early bumblebee (Bombus pratorum); and the garden bumblebee (Bombus hortorum) (Dicks, 2004).

References

Bonmatin JM, Marchand PA, Cotte JF, Aajoud A, Casabianca H, Goutailler G, Courtiade M, 2007. Bees and systematic insecticides (imidacloprid, fipronil) in pollen: subnano-quantification by HPLC/MS/MS and GC/MS. Environmental fate and ecological effects of pesticides, 827-834.

Cooper EL, 2007. Colony collapse disorder may affect complementary and alternative medicine. Evidence-based Complementary and Alternative Medicine 4 (3), 275-277.

Cox-Foster et al., 2007 A metagenomic survey of microbes in honey bee colony collapse disorder. Science Washington 318 (5848), 283-286.

Dicks L, 2004. Tumbling bumblebees. http://www.bbc.co.uk/print/nature/animals/features/340feature3.shtml

Frazier M, Mullin C, Frazier J, Ashcraft, S, 2008. What have pesticides got to do with it? American Bee Journal, 521-523.

Glinski Z, Kostro K, 2007. Colony collapse disorder – a new threatening disease of honey bees. Zycie Weterynaryjne 82 (8), 651-653.

Harries K, unda. A Place for Pollinators. Ontario Nature. http://www.ontarionature.org/onnature/earthwatch.html#1

Hulka J, Van Arsdall T, unda. National Pollinator Week, June 22-28, 2008. Second Annual Campaign to protect Bees and All Pollinators. http://www.pollinator.org/Resources/PressRelease.pdf

ISSG, 2005. Varroa destructor (arachnid). http://www.issg.org/database/species/ecology.asp?si=478&fr=1&sts=sss&lang=EN.

Kievits J, 2007. Bee gone: colony collapse disorder. Pesticide News 2007 (76), 3-5.

Lean G, Shawcross H, 2007. Are mobile phones wiping out our bees? http://www.independent.co.uk/environment/nature/are-mobile-phones-wiping-out-our-bees-444768.html

Oldroyd BP, 2007. What’s killing American honey bees? PLoS-Biology 5 (6), e168.

Osborne WD, 2007. Mysterious honeybee deaths leave sting on agriculture. FDA Veterinarian 22 (3), 9-11.

Vanengelsdorp D, Underwood R, Caron D, Hayes J Jr, 2007. An estimate of managed colony losses in the winter of 2006-2007: a report commissioned by the Apiary Inspectors of America. American Bee Journal 147 (7), 599-603.

Comments

[Rodger (My Garden is My Space) Cresswell]

In the last 20 years I have created and grown my present garden here in the UK to both please me and provide a habitat for wildlife. To me a garden without visits from a minimum of birds, bees and other insects is a sterile place.

In 2007 I noticed a decline in the number of bees but thankfully there has been a slight improvement in 2008.

Sadly 2008 has been the year when the butterfly visitors have been very few, in fact some of my old favourites have not been seen.

I can but hope this is a blip but I do fear the worst.