Data from: Supplementing small farms with native mason bees increases strawberry size and growth rate

Pollination services, especially those of bees, play a vital role in
agriculture. Declining honeybee populations require us to find alternative
solutions for sustainable agriculture. Native bees are proving to be
efficient pollinators. Mason bees (Osmia lignaria) provide valuable
pollinator services for some woody orchard species, but their value as
pollinators for herbaceous crops is largely untested. We assessed the
effectiveness of O. lignaria supplementation on nine strawberry farms over
two growing seasons. We specifically selected mason bees for this work
because they emerge from cocoons in the springtime, when few other bees
are available for pollination. Cocoons are easily deployed on farms and
emerged bees have a small flight radius, so they remain localized. We
placed cocoons on one side of each berry farm plot (our mason bee addition
treatment) but not on the opposite side (our control). We tagged and
monitored berries on nine farms throughout the growing season. We
performed statistical comparisons of berries from the treatment and
control for differences in berry growth rate and size. In addition, we
supplemented farms with native bee homes constructed from three materials
(bamboo, Phragmites and wood). This allowed us to determine whether adult
mason bees would produce a subsequent generation of bees on farms and
whether the bees had a preference for nest material type. Our work
demonstrates that mason bees can be used successfully to pollinate
herbaceous berry crops. We found that berry growth rate was significantly
higher and berry volume was significantly larger for berries from the
treatment relative to the control. We also found that adult bees
successfully utilized the bee homes for laying the next generation of
offspring and that bees colonized bamboo homes more than other home types.
Synthesis and applications. Our results are the first to show that native
mason bees (Osmia lignaria) can be used successfully to provide
pollination services on strawberry farms. Their use results in the
production of bigger berries and faster berry growth rates than managed
honeybees alone. Mason bees overwinter (and can be purchased) in cocoons,
offering great potential for efficient and effective pollination services,
for a variety of agricultural applications across different geographical
regions. The availability of suitable nesting sites and protection of
subsequent generations of cocoons from wasp parasitization warrant future
consideration.