Establishing populations of ground-nesting native bees (Colletes) for orchard pollination services

View the project final report

Commodities

• Fruits: apples

Practices

• Crop Production: pollination, pollinator habitat
• Natural Resources/Environment: biodiversity

Pollinator populations are in decline and fruit growers can no longer take their services for granted.
Relying solely on honeybees for pollination of spring flowering crops is risky due to hive rental
supply issues and potential adverse weather during bloom. Native species, including Colletes
inaequalis, have been shown to be effective orchard pollinators. Here in the Northeast, Colletes bees
are some of the first to emerge in the spring and are well adapted to adverse conditions. They can
form large aggregations of hundreds of bees nesting in sandy soils, yet they have not been managed
for pollination services. Another type of native, ground nesting bee, the alkali bee (Nomia
melanderi), is used for pollination of alfalfa in the western U.S. and farmers have become adept at
creating nesting conditions for them. We propose to take a similar approach with Colletes. We will
explore three different strategies for establishing populations of managed Colletes bees in three
orchards that we own or lease. Trials conducted over two growing seasons will be: 1) creating
suitable ground nesting conditions alone, 2) creating suitable ground nesting conditions and
introducing caged newly emerged adult bees, and 3) collecting pupae from existing aggregations in
the fall and burying them in newly created ground nesting conditions. If successful, this will help the
Project Leader’s diversified fruit farm with pollination goals and higher yields. Other fruit farmers
will will learn about this research through presentations at grower meetings and an on-farm field day
about managing native pollinators.

The goal of this project is to improve native bee pollination services in Northeastern orchards. We
want to know if it is possible to establish and manage aggregations of ground nesting bees,
especially Colletes species. If one of our proposed methods proves successful, other farmers will be
able to copy the model. The new populations of bees on our farm could also serve as a source of
bees for other fruit farms. We now propose to try three different methods to establish populations in
three different orchard sites, two with sandy loam soil and one with silty loam soil. These methods
will be 1) creating suitable ground nesting environment by removing vegetation from habitat patches
around all three orchards, and bringing in sand to an area of the silty loam based orchard, to see if
bees will move in naturally, 2) creating suitable ground nesting environments in both orchards and
caging within the nesting area newly emerged and captured adult bees, 3) creating suitable ground
nesting environments in both orchards and seeding them in the fall with bee pupae dug from other
heavily populated areas that we know about.