Pollination and pollinators
Many types of pollinators
Pollinators
• Free ecosystem service
• Links wild ecosystems
with farming
• Ag chemicals kill many
pollinators
• Not all crops have
honeybee pollinators
Basic Flower Structures
Pollination is not an accident
• Plants manipulate animal pollination
at the cost of pollen, nectar, oils and
waxes offered
• Adult bees drink nectar for sugar
• Pollen is high in protein
which bees feed to larvae
Skunk cabbage is a
native wetland plant
with beetle pollinators
Weevils Pollinate Oil Palms
red palm weevil larvae are eaten
as a delicacy in New Guinea and
Southeast Asia; Photo by Hegariz
Palm Weevil + Coconut Palm disease
•Its not a simple story though.
•Red ring fungus disease has
already killed up to 80% of
coconut palms in parts of the
Colombia.
• The disease, on a nematode
brought by the palm weevil causes
the trees to wither and die.
Eggplants in Africa
• Eggplants in Kenya are bumblebee “buzz”
pollinated (honeybees can’t do it!)
• Two species of solitary forest bees do pollinate
the eggplants.
• As forests are cleared for farming, these
pollinators are lost.
Hand pollination in Africa
Watermelons in California
• Native bees on organic farms provide 100%
pollination for organic watermelon crops.
• “Conventional” farms had greatly reduced native
bee populations + needed additional pollination.
• Conservation and restoration of native bee
habitats can be a successful strategy
Wild bees + Honeybees affect each other
The wild bumble bee + a
honey bee collecting
pollen on a sunflower.
Honey bees that interact
with wild, native bees are
up to five times more
efficient in pollinating
sunflowers. (Sarah Greenleaf
photos)
Seeds grow next years crop!
• Amaranthus greens are a traditional food
in Africa, and must be grown from seed
(hence) must be pollinated !
Valuing Pollination in $
• Foods high in vitamins and minerals like fruits
and vegetables are mostly animal pollinated
• Estimates of the value of pollination range
from $120 - $200 billion / year
• The wide range in estimated values results
from the limited tools and focus appreciating
the “free” service of pollination
• Many honeybee pollinated crops benefit
greatly from the addition of native pollinators
Estimates of crop pollination
• Bees pollinated 71 – 103 of 107 crops
worldwide (Prescott-Allan 1990)
• Bees pollinate 75% of 1330 cultivated crops
(Roubik 1995)
• Bees, birds + bats pollinate 35% world crops +
increase outputs of 87 foodcrops (Klein 2006)
Apple Pollination
Apple varieties used as good
cross - pollinators.
Hedgerows are barriers + boundaries
made up of trees, shrubs and herbs
Wind breaks,
any small
areas and
idle fields on
farms can be
critical
habitat for
pollinators
Honeybee Monocultures
• Corporate agriculture depends on only a few
species and varieties of pollinators – mostly
european honeybees
• Trucking honeybees nationwide spreads pests
+ disease to native pollinators, and reduces
genetic diversity
• Many crops are better pollinated by nonhoneybees
Pyrethrum insecticide
• The Pyrethrum, an insecticide from
Chrysanthemum flowers, is stronger if insect
pollinate the flower
Research Studies are Needed on
the Diversity of Native Pollinators
• To understand what is missing or declining, you
need to know what species exist and what the
interactions are!
• Most information on taxonomy is in museums …
• A single database to share information needed
• Native crops usually have
local native pollinators –
but little is know about them
The Pollinator Matrix
• Native flowers may have different pollinators over
time (years)
• As each species flowering is limited to a specific
part of a season, pollinators need many different
species of flowers (and hence different species of
plants) to survive over the year/season.
• Pollinator populations may vary due to many
environmental variables – parasites, habitat
changes, climate
• So, pollinator diversity depends on plant diversity
Human Ecosystem Disturbance
• So, a variety of flowers and pollinator types help
to keep ecosystems functioning… until…
• Humans disturb habitats with large monocultures
and chemicals impacting native pollinators… so
pollination service is lost
• So….Humans turned to European + Asian
honeybees to fill the loss