Numerous studies in many parts of the world are showing a
dramatic fall in insect numbers. They’re essential for agriculture, and
essential in a garden where fruiting plants are grown, including our beloved tomatoes. Habitat loss, monoculture farming, and the widespread use of insecticides are
among the reasons for this decline.
For a long time, many home gardens were unwelcoming to
pollinators. We had monoculture lawns, heavily mulched and tidy flower beds,
and until the pesticide act in 2008, there was regular spritzing and spraying
of everything in sight, indiscriminately wiping out beneficent insects. This didn’t
end pesticide use, only the formulas changed to comply with the law. Shelves
are still filled with sprays and powders to rid gardens of pests, and beneficial
insects can be killed just as effectively as before.
One of these important insects that specifically needs our
help is the humble bee. Not including the honey bee, a non-native species,
there are over 800 distinct types throughout the country, 400 of which can be
found in Ontario.
But if it's honey you want, we rely on the honey bee. Did you know that a good part of your honey may have come from
insect poop. Yes, you heard that right, and I apologise if you’re drizzling
honey on your cereal right now. A study of the DNA in honey carried out by Noah
Wilson-Rich, an entomologist who founded The Best Bees Company, revealed that
fact and other valuable information. The study sampled urban hives in major
cities across the US and the preliminary results are surprising.
We naturally assume that honey bees are busy collecting
nectar and pollen from flowers, and we know they do because we watch them doing
it. It’s a biased perception, however, as it’s easy to see the plants that bees
are visiting in our gardens. We’ve not been paying attention to what they do at
higher altitudes, and that’s one of the major discoveries that was made when
the DNA in honey was studied.
The main sources of sugar in the honey tested did not come from
wildflowers, but from trees, and not only from the blossoms; it also came from
the excretions of sapsucking insects, particularly aphids, those pesky critters
that drive gardeners wild when they find them munching away on plants.
What goes in one end of a hungry aphid is the sap that the
plant depends on to grow and flourish. Too many aphids and the plant can die. It’s
what comes out of the other end of the aphid that attracts the bees. It’s a
sweet, sticky substance called honeydew. Besides nectar from flowers, honeybees
are slurping up honeydew, and there’s often plenty of it. We might see only a
few aphids on plants in our gardens; up in the treetops there can be tremendous
numbers — easy picking for bees, and there’s even more food available when a
tree is in bloom, far more than in a garden below.
Whether from nectar or from honeydew, the study determined
that 75% of the sugar collected by honeybees came from trees and not from wildflowers,
especially in an urban setting. Although more native wildflowers than ever are
being introduced into urban gardens to benefit pollinators, there’s often a far
wider range than is present in a natural, rural area. In Boston, where interest
in urban beekeeping has grown dramatically, the honey sampled contained the DNA
of 411 plant species. Because of this larger diversity of plants, the hives
there appeared to be healthier and more productive than rural ones.
Another discovery made by the researchers was regarding the
types of trees and flowers the honeybees preferred. Surprisingly, the flowers
and trees favoured by them are not necessarily native ones. Honey bees don’t
seem to care where lunch comes from. Even though coniferous trees are
predominant in Seattle, the bees there favoured non-native linden and cypress trees.
Preferences varied from city to city because of the
popularity of particular plants in a specific region. For instance, in New
York, where even luxury hotels keep rooftop hives, the top three plants were
locust and linden trees, and the flowers of sedum. In Portland, Oregon, known
as the city of roses, no surprise that roses were in the top three along with
begonias and sweet chestnut trees.
In San Francisco, where non-native eucalyptus trees have
become an invasive species, there’s currently a debate going on whether to fell
them or give them protection. The honeybees are not fussy. They’re such
generalists, they don’t care that the trees are from Australia. They love them.
Making up their top three favourites there are pine trees and rosemary.
Next time you hear buzzing in your garden, remember to look
up, way up.