Establishing populations of ground-nesting native bees (Colletes) for orchard pollination services
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.
In April 2017, we tried three different methods to establish a population of ground nesting bees on one farm as opposed to the three orchards planned. We were not able to find sufficient numbers of overwintering cocoons or adults to try our methods in three different orchards. From our experiences trying to source wild bees, we adapted our methods to depending on freshly caught adult bees from aggregation sites as an establishment strategy.
The three methods trialed at The Farm Between were:
1) created a suitable ground nesting environment by removing vegetation from a habitat patch
in an orchard and added 5 previously dug pupae from fall 2016, 2) created a vegetation free habitat patch and added 5 female and two male adults caged for 24 hours, 3) dug a pit and brought in sand to an area of a silty loam based orchard, then caged within the nesting area 20 female and 5 male newly emerged and captured adult bees along with floral resources for three days.
In November 2017, John spent 2 hours searching for pupae in the area where he had captured adults in the spring. None were found.
We won’t know if the establishments were successful until the spring of 2018 when adult bees emerge. The bees that were caged for 3 days showed signs of digging nesting holes in the sand provided. There was no clear evidence of bee activity in the other 2 trials. Not finding pupae in the fall in an area that was marked as an aggregation was discouraging. We will now focus on collecting newly emerged spring adults as a way to innoculate new orchards. We hope to collect enough bees in 2018 to try our 3 day caged adult method in 3 different orchards.
No conclusions until research observations are finished