My research forms just a small part of the
Global Pollination Project (GPP) run by the Global Environment Facility (GEF), who
fund several projects undertaken in seven partner countries: Brazil, Ghana,
India, Kenya, Nepal, Pakistan and South Africa.
The GPP is implemented through the United Nations Environmental
Programme (UNEP) and executed by the Food and Agriculture Organization of the
United Nations (FAO).
In South Africa, the GPP is being implemented by
SANBI’s Applied Biodiversity Research Division based in Cape Town. Several pollination projects have been
initiated in South Africa and will run during a 5 year period from 2009 until
the end of 2013. The projects focus
specifically on the pollination of agricultural crops and three crop types were
chosen for the South African projects:
1. Appels (near Elgin & Ceres, Western Cape)2. Onion seed (near Oudtshoorn, Western Cape)
3. Sunflower seed (near Bela-Bela, Northern Province)
These crops are dependent on animal pollination for successful production and quality produce.
I work on the onion seed pollination
project. The project specifically
focuses on hybrid onion seed, where the bisexual flowers of the “male” parent plants
produce pollen, and are crossed with “female” plants whose bisexual flowers do
not produce pollen. This out-crossing
insures the production of sterile seeds.
The carrying of pollen from the “male” flowers in one row, to the
“female” flowers in the next row, are solely done by insect visitors to the
flowers. Therefore, hybrid onion seed
growers are totally dependent on the work done by honeybees and other
insects. If the honeybees do not visit the
onion flowers, the crop will fail to produce any seed.
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| Picture 1: This crop of a hybrid onion seed cultivar clearly illustrates the commonly used planting formation of male-fertile and male-sterile rows of onion plants. The male-fertiel rows in this example are a lighter, greyish green and are planted on the sides and in the middle of each section. The difference between 'male' and 'female' rows are not always very obvious. |
Onion crops are very labour intensive to produce
and require large amounts of inset costs, but successful crops are highly
profitable. Seed growers need to
overcome several challenges in producing a successful crop. Onion plants are considerably susceptible to
fungal and bacterial diseases, therefore they grow best in dryer climates. Onions are also targeted by thrips,
especially in drought years, and considerable amounts of pesticides are used to
control pests and pathogens. However,
during flowering, no pesticides are sprayed to ensure the survival of
pollinator insects and their attraction to the crop. They’ve got an important job to do.
My job is to find out who the visitors to the
flowering hybrid onion seed crops are, how abundant they are, where they come
from, and how efficient they are in pollinating the crops (just to put it
simply). Because pollination is so
crucial to successful hybrid onion seed production, most seed growers are not
taking any chances and stock the crops with up to 10 honeybee hives per hectare
to try to ensure adequate pollination.
The largest seed crop I’ve work on was about 6 hectares which was
surrounded by 59 active honeybee hives (Pictures 2&3).
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| Picture 2: The 6 hectare hybrid onion seed crop in the great Karoo near Laingsburg, stocked with 59 hives (visible as small squares around the field) |
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| Picture 3: The same field, from a distance |
You might think to yourself now: “Hey, but you
know who’s doing the work then, the honeybees off course.” And you are right. Honeybees, according to me, do most of the
work. But it becomes more complicated
than that. The honeybee is in indigenous
species in South Africa and is the most abundant wild pollinator in our
ecosystems. Therefore, here in South
Africa and elsewhere where the honeybee is an indigenous species, we
differentiate between two different types of honeybees based on the source from
where they provide services to agricultural production. Managed
honeybee colonies, housed in the commonly used Langstroth hive, is an economic service
supplied by beekeepers to several agricultural producers like seed
growers. While wild
honeybees living in the environment supplies an ecosystem
service to seed growers when they visit and pollinate their
crops. All the wild (not managed)
insects visiting and pollinating agricultural crops are supplying an ecosystem
service to farmers. The cost to rent a
hive of honeybees to pollinate your crop was between R250 and R270 per hive in
2010. While the pollination services
provided by insects from the ecosystem is totally free! Even though they supply a very valuable
service to our food production!
The GEF research projects' main focus is to determine the amount of pollination ecosystem services received by farmers in the participating countries, and to what extent the production of the selected crops are dependent on and/or improved by receiving these 'free' services.
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| Picture 4: A honeybee working on an onion umbel. |
