 |
Man-made
bee houses
Good
replacement for holes in old logs
©Beatriz
Moisset
|
Do you ask yourself: where do
pollinators go in winter? We see them through the warm seasons
visiting flowers and doing their invaluable job. But, then what
happens to them? Putting aside the few, such as hummingbirds and
monarch butterflies, which fly to better climates, all the others
find a secluded place to spend the cold months. Like hibernating
bears, many fatten themselves by stocking up on supplies and then go
to sleep. Others rest as eggs or in an immature state such as a larva
or pupa. Either way, they need a sheltered space safe from predators,
parasites and excessive cold.
I know that some gardeners, with the
best of intentions, destroy these vital shelters. It may be a good
idea to take a look at all the places used by pollinators during the
winter. This is one case in which a little untidiness may be a good
thing.
Most bees are ground nesters; this
means that they build their nests in the ground, preferably a bare
spot, dry and sunny and not subject to flooding. Sometimes there is a
patch large enough for a whole town of nests; other times, just a few
square inches of soil free from vegetation fill the needs of one
enterprising bee raising a family. The mother bee dies at the end of
the season, her mission accomplished. Her babies will emerge from the
nests next spring.
 |
Ground nest
of a digger bee
©Beatriz
Moisset
|
 |
Not
anthills but a small town of
Lasioglossum
bees
©Beatriz
Moisset
|
Bumble bees find some nook or cranny
underground, perhaps under a tree root, a log, or even an old wall.
The difference here is that the overwintering pollinator in this case
is the adult, already mated and fertilized female which will start a
whole new colony next spring.
One of my favorite bees,
Augochlora pura, doesn’t nest underground. Instead it finds a dead log, whose bark is beginning to peel, and builds its nest under the bark.
The younger generation emerges at the end of summer. They mate, and
the new bees find shelter, once again, under loose tree bark. Many
old dead logs serve as wintering shelter for this bee.
 |
Two
Augochlora pura females
getting
ready for winter in November
©Beatriz
Moisset
|
 |
A sleeping
beauty under bark in mid January
©Beatriz
Moisset
|
 |
Sleeping
Beauty’s castle, old logs
©Beatriz
Moisset
|
Other bees, including mason and
leaf-cutter bees, use hollow twigs or holes dug by beetle larvae in
trees. Bee houses that imitate these conditions are gaining
popularity among gardeners and mason bees readily accept them. This
is becoming a necessity in our suburban gardens, where old trees with
beetle holes are rare. Clumps of dried grasses or the hollow canes of
plants such as hydrangea or brambles are also valuable to nesting
bees if they are allowed to stand through the winter and early
spring.
 |
Hollow
twigs are a winter haven
to many
pollinators
©Beatriz
Moisset
|
Bees are
not the only pollinators. Butterflies and moths do a good job too; so
let us take a look at a couple of them.
Fritillary caterpillars feed on
violet plants. In the fall, when the adult butterfly is ready to lay
its eggs, these plants are wilting or totally gone. The female lays
its eggs near the remnants of violet plants or in the most likely
places for violets to grow. Even if many eggs are lost, there are
enough left to maintain the populations year after year. The curious
thing is that the eggs hatch in the fall when there is nothing for
the caterpillars to eat. So the tiny newborns bury themselves a
little deeper and go to sleep until the next spring. By then, their
food is ready and waiting for them.
Hummingbird moths (
Hemaris), those
colorful tiny pseudo-hummingbirds (I have seen many people fooled by
them) have a different strategy. Their eggs hatch in the summer and
the caterpillars feed on one of their favorite plants. They are not
very choosy, from honeysuckles, to viburnums, to blackberries; all of
them are good for the several species of hummingbird moths. In
autumn, the fully grown caterpillar drops to the ground, buries
itself under the leaf litter and becomes a pupa. Now it is ready for
winter.
 |
A patch of
leaf litter serves as a winter home
to some
pollinators
©Beatriz
Moisset
|
Numerous variations on
these general themes exist. Not just pollinators, but also a number of
other insects, some of them beneficial predators of pest insects,
take advantage of the mentioned wintering spots. We can conclude
that: bare spots, dead logs, dried up grasses or other shrubby plants
and leaf litter are all vital to pollinators and to other creatures,
all of them important components of a garden ecosystem. The perfectly
manicured garden may appeal to a certain idea of esthetics but it is
a monstrosity from the ecological point of view. Some of us need to
readjust the way we view a garden.
There is great beauty in the mechanism
of how an ecosystem works. I relish this beauty so I find it easy to
accept the visual impact of an “untidy” garden in need of some
raking, re-sodding, log removal, leaf litter removal, etc.
Also see:
Helping Native Pollinators Winter Over Sierra Club
