Once in a while, I come across something that I’d love to share but that doesn’t call for a longer blog. So I decided to try out shorter pieces that I’m calling “Footnotes,” i.e. a little extra nature information that might intrigue or delight you as it did me. Here’s a discovery Dr. Ben VanderWeide, our township Natural Areas Stewardship Manager, shared with me in the last ten days.
Native “spring ephemerals” are wildflowers that surge up out of the earth in early spring before the trees leaf out so they can capture as much sunlight as possible. On April 13, at Ben’s prompting, I hiked to the crest of the sledding hill at Lost Lake Nature Park to see one of my favorite ephemerals festooning the landscape with dashes of lavender blue. Hepatica blossoms (Hepatica americana) don’t last long and the snow this week may have shortened their season. But I wanted you to know about them so we can all look for them again next spring.
Fortunately, some species of native bees emerge from their winter nooks and crannies at the same time as the ephemerals and buzz directly to their favorite wildflowers. As they forage for nectar, their bodies become dusted with yellow pollen. Once they mate, they stash some of that sticky, nutritious food in their nest to feed the next generation of native solitary bees. Despite their short adult lives – most live only 4-6 weeks above ground – these native bees do a fine job of pollinating as they rush from blossom to blossom, shedding bits of pollen as they go. Nice reciprocal relationship evolution came up with, eh?
The little bee above is a solitary bee from the genus Ceratina called the Small Carpenter Bee. Solitary bees are not aggressive, because unlike European Honeybees (Apis mellifera), they don’t need to defend a colony filled with honey, workers, larvae and a queen. So our native bees rarely sting and provide crucial pollination services for native plants like Hepatica.
In our region, these native bees usually produce only one generation. Adult solitary bees emerge from last year’s nest and once mated, the female buzzes the area seeking a pithy, upright stem from one of last summer’s perennials. They chew the pith from the center of the stem and use it to make separate cells within the stem, provisioning each with a pollen packet to feed the larvae once the eggs hatch. If such stems aren’t available close by, they may excavate small cavities in rotting wood. I’ve learned lately that those of us who value native plants and bees should leave hollow, dry, sturdy stems standing after the flowers die back. If we cut off about one-third of the stem and leave the rest, we’re creating nesting material for next spring’s hatch of harmless and very beneficial native bees!
Despite its name, the larger Carpenter Bee above (genus Xylocopa) is not a relative of either the Small Carpenter Bee (genus Ceratina) or the Bumblebee (genus Bombus) which it resembles. The shiny and hairless abdomen of a Carpenter bee lacks the stiff hair and fuzzy appearance of a Bumblebee’s abdomen. A Bumblebee flicks out its very long tongue to reach into deeper flowers. But a Carpenter Bee’s shorter mouth parts make it a very effective pollinator for open-faced, shallow flowers like Hepatica. Like most of our native bees, the Carpenter Bee rarely stings. The males will occasionally buzz around us while looking for a mate but have no stingers. The females only sting if handled or hassled. But Carpenter Bees can present us humans with a different challenge.
These bees nest by drilling neat round holes on the undersides of wood – like a limb or the cedar railings on our deck, I’m sorry to say! Once inside, they excavate a tunnel which runs with the wood grain and then construct separate chambers stocked with pollen for each egg they lay. Woodpeckers eat Carpenter Bees (ouch!). According to Wikipedia, if Bluejays (Cyanocitta cristata) detect the sounds of bee larvae within the wood, they may further excavate the bee’s neatly drilled hole in their search for another snack – doing more damage than the bee did! We’ll try to encourage our Carpenter female to move her linear nursery to the plethora of trees in our woods. I’ve read that she may object to the scent of citrus oil so we may spray some beneath our railings this spring. Wish us luck. I think we’ll need it. If it doesn’t work, oh well. Killing native pollinators isn’t an option for us. So I imagine that we’ll fill the holes beneath the railings once the young have left and go on with our lives.
So that’s the first “Footnote.” I hope you enjoyed this inaugural foray into a new format. Many thanks to Dr. Gary Parsons, Collection Manager and Bug House Director at the Entomology Department at Michigan State University for helping me again with bee identification. Please watch for these shorter pieces sprinkled between the longer blogs throughout the year. I’m sure Ben and I will come across many more small wonders to share!