Monday, October 10, 2016

Reciprocity for the pollinators

Even this hoverfly needs a winter home. Yup! That's not a bee.
Insect pollinators can spend the winter in a variety of life stages and this varies, depending on the species. Some have eaten a lot to make it through the winter; others wait in suspense as larvae, pupae or eggs. Most native bees spend the winter in their nest cells as pupae, emerging as adults the following spring or summer, so it is critical to protect nesting areas from disturbance all year long, not just during the nesting season.  Old bark, cane, leaves and especially undisturbed soil are the winter homes of pollinators.
Bumble Bee in my garden!

One exception is bumble bees, which do not overwinter in their nests. Bumble bees are unusual in that they can still forage in very cold temperatures due to internal thermoregulation. But in fall, all the males die off and the new queen searches for a log, tree root, leaf litter, loose soil or other niche where she waits, already mated and fertilized, to emerge and begin a new colony when the weather warms.

Another bee that seeks out logs for winter is the bright green sweat bee, which prefers to nest under peeling bark. Dead logs are particularly attractive locales. Like her cousin the bumble bee, it’s only the female that overwinters, and she must quickly rebound to raise a brood in spring.

Some native bees snuggle into hollow twigs or the pathways dug by beetle larvae in trees. Mason and leaf-cutter bees count on these sources, as well as clumps of dried grasses or hollow canes from brambles or other woody plants, to provide shelter during the winter.

The majority of native bees nest in the ground, finding a sunny spot that won’t flood. It may be a few inches of bare soil with one nest, or a colony occupying several feet. You may have mistaken them for anthills or spider holes. Usually, the mother bee dies at the end of the warm season, leaving her babies to emerge in spring.

Cecropia moth found at a gas station this summer.. Not a lot of habitat at a gas station.

Butterflies and moths also overwinter in a variety of stages (egg, larva, pupa, adult) and use plant matter to insulate themselves for the winter.

While the monarch flies south to overwinter in Mexico, most other butterflies stay put and take shelter somewhere dry and safe until spring. Some butterflies, like the mourning cloak, comma, question mark, and Milbert’s tortoise shell, overwinter as adults. They nestle into rock fissures, under tree bark, or in leaf litter until the days grow longer again and spring arrives. Butterflies that overwinter in a chrysalis include the swallowtail family, the cabbage whites and the sulphurs. Many of these chrysalises can be found either hanging from dead plant stems or tucked into the soil or leaf litter.

Tiger Swallowtail found on one of my hikes this past summer.

Tiger swallowtails that hatch in the summer feed and molt five times, then pupate and hatch in as little as 15 days. But when the caterpillar pupates in the fall, the chrysalis is brown instead of green to match the woody brush where it hangs, and the butterfly won’t emerge until spring. 

And still other butterfly species, such as the red-spotted purple, the viceroy, and the meadow fritillary, spend the winter as a caterpillar rolled into a fallen leaf or inside the seed pod of a host plant.

Pollinators need sheltered areas in which to spend the winter. To provide these safe havens, set aside undisturbed patches of habitat allowing leaf litter, standing dead twigs or stems, and other ground cover to remain. Do not till soil where there might be ground nests. Some other pollinators spend the winter in tall grass, bushes, trees, piles of leaves or sticks, or on man-made objects. In general, the best way to protect pollinators in the winter is to leave them alone.  If you need to manage your pollinator meadows by mowing or burning, try to do so in the late summer or fall while the insects are still active and can get away. 
It's worth leaving some overgrown, weedy spots, designated pollinator areas, to give these important insects a winter home. 
Bumblebees buzzy about in the flowers
These are the insects you will gladly welcome come spring and summer in your garden, so why not give them a winter home in return for their pollination of your garden?


  1. A very well written and interesting piece on fall prepping for pollinators. Thanks for sharing this and guiding us on the walk tonight and keep on writing!

  2. Finally got the images to work!!