1. Pollination and the Use of Bees to Help Grow Food for the World
Chester County Envirothon
January 8, 2019

2. Jack McMichael treasurer@chescobees.org
Jack McMichael

3. Agenda Bee Biology/Anatomy & Lifecycle Types of Bees
Bees’ Role in Pollination
Recent Pollinator Decline
Requirements for Using Bees in Crop Pollination
Providing Ample Habitat & Forage for Native Bees
Impact of Insecticides on Pollinators & Integrated Pest Management (IPM)
Summary
Q&A

4. Bee Biology/Anatomy & Lifecycle
Bees, along with wasps, ants & sawflies are part of the Order Hymenoptera of the Insect Class.
All insects have 3 main body parts: Head, Thorax, Abdomen.
Bees have 6 legs, long antennae and 2 pairs of wings.
There about 4,000 species of bees native to North America.
During the first 3 life stages, the bee lives in a brood cell within the nest.
After emerging from their cell, the adult bee generally lives from about a week or two to six months, varying by species and gender.
A bee’s life cycle has 4 stages: Egg, Larva, Pupa & Adult.

5. Types of Bees – Solitary vs. Social
Most bee species are solitary bees in which each queen makes her own nest, lays eggs in individually sealed cells and after providing pollen and a small bit of nectar, seals the cell.
After provisioning the last cell in the nest the queen seals the nest closed, and flies away for the short remainder of her life, before dying or hibernating, not tending to the young or ever seeing them emerge as adults.
European Honey Bees, Bumblebees and most stingless bees are eusocial bees with multiple generations living and working together in the colony. Most stingless bees are tropical or sub- tropical in distribution, and not found in our area.
There are 3 castes in a social bee colony: the queen (generally the mother to all the other bees; male drones, and; unmated female worker bees.

6. Types of Bees – Native vs. Non-Native
The European (or Western) Honey Bee is not native to North America. They were first brought here with the English settlers to Virginia in the early 1600’s to pollinate the crops those settlers hoped to grow in the New World.
Feral (wild) honey bees generally build their nest in an enclosed cavity with a small, easily defendable opening, 15 feet or more above the ground.
Honey bees readily accept man-made hives as their homes.
Of the 4,000 species of native bees in the U.S., - 70% build their nests in the ground, with the remaining 30% building their nests in wood, generally closer to the ground than feral honey bee nests. Q

7. Bees Role in Pollination
Pollination is the reproductive process within plants whereby pollen from the male portion of the plant (stamen) is transferred to the female part (pistil) of another plant of the same species or a different part of the same plant.
Grains and grasses rely on wind for pollination while most other food crops, flowers and trees rely on animals for pollination.
Animal pollinators include bees, butterflies & moths, bats, birds, beetles and a few others.
The majority of North American plants are pollinated by bees with bees providing about 80% of the U.S. crop pollination.
About one in every three mouthfuls of food and beverage we consume is a product of pollination by bees.

8. Bees Role in Pollination
Modern farmers have historically relied heavily on honey bees for pollination of their food crops.
Bees entire diet consists of nothing but water, pollen (protein) and nectar (carbohydrates) which makes them efficient pollinators.
Bees have existed in great numbers. In addition to the local native bees, commercial beekeepers in the U.S. in the 1960’s owned and managed roughly 6.5 million honey bee hives.
Honey bees forage during the daylight but always return to their hives each night.
Honey bee hives are relatively easy to transport, and can therefore be efficiently moved to different locations to follow the crop blooming cycles - Migratory Beekeeping.

9. Recent Pollinator Decline
While the populations of all pollinators are declining, the population of honey bees has been particularly hard hit.
Since 2007, the average annual decline in the number of managed honey bee colonies in the U.S. has been just less than 38%. Commercial beekeepers now own about 2.75 million hives.
Within Pennsylvania, the average annual loss for the past 5 years has been over 51%, and about 45% over the same 10-year period.
The varroa mite (V. destructor) & the 14+ viruses it carries are the primary factor in this decline, but the loss of habitat and forage (food sources) are significant loss drivers as well, and are largely the result of human interaction.
Large monoculture farms, and the general loss of forage and habitat has also impacted most native bee species and other pollinators. Q

10. Requirements for Using Bees in Pollination
With the significant decline in honey bee populations, food growers are looking for ways to increase the pollination services their crops receive from native bees. In order to do this, farmers must address two issues:
Where any native bees currently live (or can be attracted to live) nearby their crop locations (habitat), and;
The food sources (forage) currently available (or that can be made available) near the crop locations, not only when the crops are in bloom, but also at other times of the year when the bees will need to be sustained for the balance of the growing season.

11. Requirements for Using Bees in Pollination
A 3-Step approach is recommended for increasing the pollination services provided by native bees that may already be in the vicinity of the food crops:
Learn to recognize, and then search for the native bees and bee habitat that are already on or near the farm;
Adapt existing farm and land management practices to avoid harming the bees already present, and;
Provide increased habitat and forage for the native bees on and around the farm.

12. Providing Habitat for Ground Nesting Bees
Most native bees travel less than half a mile to forage for nectar and pollen, therefore potential nesting sites must be in close proximity to the food crop fields.
Maximize sunny areas around the food crop field where the ground remains undisturbed, with semi-bare, well drained soil having some slope for drainage to attract ground-meeting bees. If necessary, and some sand to clay soils.
Avoid tilling ground where native bees are nesting whenever and wherever possible.
While artificial nests for bumblebees are commercially available, their success rate is less than 30%.

13. Providing Habitat for Wood Nesting Bees
Do not remove standing dead trees (snags) that do not pose a safety hazard, and drill some small horizontal 3”-5” deep holes 3/16” in diameter in them to attract Mason/Orchard bees.
Build a “Bee House” from a 4”x4”, to 6”x6” wooden block with 3” to 5” deep holes of 3/32” to 3/8” diameter drilled into one side of them on ¾” centers and ¾” from the block edges as a nesting site for various species of wood nesting bees. Add a small overhanging “roof” to provide protection from rain and hot midday sun.
An alternative is to bundle a couple dozen hollow stems of bamboo, teasel or common reed, cut just below the node (often indicated by a narrow ridge on the exterior) and make sure all the stems or straws are closed on the same end. Then place the bundle in a can, length of PVC pipe or similar container and mount so that the tubes run parallel to the ground or just slightly lower on the open ends.

14. Providing Habitat for Wood Nesting Bees
The wooden nesting blocks or bundles of stem tubes should be mounted about 4 feet off the ground in an eastern or southeastern facing location that gets morning sun but some protection from sun in the hottest part of the day. This allows the bees to warm rapidly in the morning and begin foraging. Make sure they are fastened securely so that they do not move in the wind.
To reduce the population of parasites that also use the holes in the blocks and hollow tubes for homes, it is recommended that you replace these structures every 3 years. Use multiples of each structure type and replace them on alternate years to ensure that ample bee populations are available each year.

15. Providing Forage for Native Bees Near Crops
It is not enough to provide places for native bees to nest near the food crops. Providing ample food sources for the entire annual life cycle of the bees is equally important or they may soon relocate to someplace else where food is abundant.
Plant a wide variety of plants that provide a succession of blooms throughout the growing season, and will require minimum maintenance once established.
Preference should be given to native plants first, then non-invasive, non-native plants when necessary.
Pollinator diversity increases with forage diversity. Different bee species are attracted to different sizes, shapes, colors and types of flowers.

16. Providing Forage for Native Bees Near Crops
Forage provided for bees should include continuous floral resources with overlapping bloom times throughout the growing season (February-November).
It is critical to include plants that bloom early in the season, as well as late in the season.
More available forage early in the season will lead to greater bee reproduction and more bees for pollination services later in the year.
Late blooming plants will help support honey bee colonies within a few miles as their entire colony survives through the winter. Q

17. Impact of Insecticides on Pollinators
Insecticide poisoning of bees (particularly bumblebees) has been well documented for decades.
Even if the bees are not killed outright by the insecticide, exposure may cause other issues including:
Dementia so that the foraging bees cannot navigate back to their nest;
An inability for the bees to fly at all;
Agitated behavior, wobbly movements or paralysis.
Any of these conditions can impede nest building, foraging, and lead to premature death of both the bee and her offspring.
Insecticide use should be eliminated or reduced whenever possible.

18. Integrated Pest Management (IPM)
A decision-making framework for using the least hazardous pest management options when there is demonstrated need, both within conventional and organic farming systems.
It employs a four-phase strategy:
Prevent conditions that favor pests;
Establish an economic threshold;
Monitor pest populations and/or pest damage;
Take action to control pests only when populations or damage exceed the economic threshold.

19. Reducing Risks from Insecticides
Chose insecticides that have the least impact on bees, - those with active ingredients that only target specific pests.
Avoid broad-spectrum insecticides that are generally toxic to all insects. Use formulations that are safer for bees.
Control “drift” through local, near grould-level application in little or no wind.
Apply insecticides when crops are not blooming and on warm nights of low humidity when the bees are not foraging, whenever possible.
Follow label guidelines to protect honeybees.

20. Summary
Bees are a primary and necessary source of food crop pollination, responsible for pollinating about 80% of total U.S. food crops.
There are about 4,000 native bee species in North America, with 70% of those being ground-nesting bees.
Most bees are solitary bees, with honey bees and bumblebees being the major exceptions in our area.
With the decline in honey bee populations, growers must look to native bees to provide needed pollination services.
Growers should first identify what native bees exist on or near the farm, and protect their homes and existing food sources.
Next, they must provide additional habitat and forage resources to attract more native pollinators, and employ IPM to manage other crop pests with minimal harms to the bees. Q

21. Thank You!
Photo by Ivar Leidus / CC BY-SA 4.0