> While discussing the influence of honey bees pollination
on food
> production, let me say that I'd be *most* interested to
see the data
> underlying the oft-repeated claim that 1/3 of our food
requires bee
> pollination.

Hi Allen

McGregor was the source of the quote: 'it appears that
perhaps one-third of our total diet is dependent, directly
or indirectly, upon insect-pollinated plants'.  See here for
more details:
http://gears.tucson.ars.ag.gov/book/econ.html

I looked at the FAO figures, and it is clear that the big
crops are wind or self-pollinated - but that large numbers
of crop species (many more than a third) are insect
pollinated.  I'll paste the relevant text and table from a
book chapter below - with apologies for the table
formatting.

all the best

Gavin.

From: Ramsay, G (2005) Pollen dispersal vectored by wind or
insects. In: GM Crops and Gene Flow, Eds GM Poppy and MJ
Wilkinson.  Blackwell Scientific Press, Oxon.

Although the world’s most important food crops are cereals,
clearly adapted for wind-mediated pollination, a very large
number of other crops require insects for efficient
pollination and seed or fruit production.  McGregor (1976)
estimates that about one third of all food consumed is
attributable, directly or indirectly, to insect pollination.
In Table 1, most of the crops listed in the top 51 require,
or benefit from, insect pollination, at least during the
seed production phase.  In most cases the primary insect
pollinators are bees.  As agricultural production has
intensified, populations of native pollinators have
declined, due to both habitat loss and the use of
pesticides.   Bees have been noted to be pollinators for 77%
of 82 species commodities, and are the most important known
pollinator for 48% of them (Prescott-Allen and
Prescott-Allen 1990, Delaplane and Mayer 2000).  Various
figures have been derived for the value to the economy of
this pollination effort.  In the US, the value of honey bee
pollination was placed at US$9 billion in 1989 (Robinson et
al 1989).  For the EU, the value of honey bee pollination
was placed at €4.3 billion in 1989 (Delaplane and Mayer
2000).  Such a high dependence on managed and wild bee and
other insect pollinators for sustainable cropping requires
more than managing crop agronomy effectively.  An integrated
approach to the whole system is required, ensuring that
introduced, managed pollinators are not damaged by
agricultural practices, and that wild pollinators together
with the surrounding habitats which support them are
maintained for current and future generations.

Table 1.  World crops: their pollination requirements and
production in 2003.

Crop 1. Production Harvested product Pollination 2.
              Mt x 1,000
cereals
Maize                   638.0 seed wind
Rice, paddy         589.1 seed self (wind)
Wheat                  556.3 seed self (wind)
Barley                  141.5 seed self (wind)
Sorghum               59.6 seed wind
Millet                      29.8 seed wind
Oats                       26.3 seed self (wind)
Rye                        14.9 seed wind
Triticale                 10.2 seed self (wind)
roots, tubers and vegetables
Potatoes             310.8 root/tuber n/a 3.
Cassava             189.1 root/tuber n/a
Sweet potatoes 121.9 root/tuber n/a
Cabbages            66.0 vegetative insect
Onions, dry           52.5 root/tuber insect
Yams                     39.9 root/tuber n/a
Carrots                  23.3 root/tuber insect
Lettuce                  20.8 vegetative self (insect)
Cauliflower           15.9 vegetative insect
Garlic                    13.7 root/tuber n/a
Spinach                11.9 vegetative wind (insect)
fruit
Tomatoes           113.3 fruit self (insect)
Watermelons        91.8 fruit insect
Bananas                69.3 fruit parthenocarpic
Grapes                  60.9 fruit insect 4.
Oranges                60.0 fruit insect
Apples                   58.0 fruit insect
Cucumbers           39.6 fruit insect
Plantains               33.0 fruit insect
Eggplants             29.0 fruit insect
Melons                  26.7 fruit insect
Mangoes              25.6 fruit insect
Capsicum             23.2 fruit insect
Other citrus           21.0 fruit insect
Pumpkins, sqshs 19.0 fruit insect
Pears                    17.2 fruit insect
Peaches/nectrns 14.8 fruit insect
Pineapples          14.6 fruit parthenocarpic 5.
Lemons and lmes 12.5 fruit insect
Plums                   10.1 fruit insect
grain legumes
Beans, dry           19.0 seed self (insect)
Peas, dry             10.2 seed self
oil and industrial crops
Sugar cane      1333.3 vegetative wind
Sugar beets       233.5 vegetative wind (insect)
Soybeans          189.2 seed self
Oil palm fruit      143.4 fruit insect and wind
Seed cotton         56.1 fruit insect
Coconuts             52.9 seed insect
Rapeseed           36.1 seed self and insect
Groundnuts         35.7 seed self
Sunflower            27.7 seed insect
Olives                  17.2 fruit wind and self (insect)

1.  Of the 144 commodities monitored by FAO only those with
production of at least 10,000 Mt are presented here.  2.
Where a vegetative part of the plant is harvested, this
refers to pollination during seed production.  3.  n/a - not
applicable, propagated and harvested vegetatively, although
potatoes are grown from true seed in some parts of the
world.  4.  This and other fruits may have parthenocarpic
forms.  5.  Wild and seeded forms are pollinated by
hummingbirds.

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