In praise of wasp architects
Commending yellowjackets for surviving two storms, Indigenous Peoples' Day, and flower of the week
Here at Possum Notes, as the name suggests, we sometimes shine a light on creatures of ill-repute and celebrate them for a moment. The bald-faced hornet (Dolichovespula maculata) is that creature this week.
At the outset, I’ll make clear that I completely understand anyone who has had to remove a wasp or hornet nest close to highly-trafficked areas because of concerns about people with allergies getting stung. Wasps are territorial, and if they have decided their territory is the overhang above the garage door, that may put you in conflict with them. But wasp nests sited a reasonable distance from human hotspots — those we have less reason to worry about. To get specific and to avoid playing armchair pest-manager, Penn State Extension advises that nests more than 10 feet away from entryways are probably safe to leave up.
The wasp architects of southeastern Massachusetts have my commendation for their work this season. I’ve gotten a good look at two nests that have now survived intense storms with downbursts of rain and wind that caused widespread power outages in the South Shore, including to our apartment.
A sizable bald-faced hornet nest in a rural area south of Boston
This got me interested in how the wasps managed to construct a nest of such durability. Bald-faced hornets — which, by the way, are not true hornets (wasps in the genus Vespa) but an odd-looking yellowjacket wasp (genus Dolichovespula) — chew up wood to form pulp that hardens into a cardboard-like material. The nests that I’ve seen have multiple attachment points to branches, which I suspect was key to their survival through coastal wind storms. It begins when a queen wasp creates a small structure with just a few cells. But by season’s end, which is when many of us finally notice we’re sharing space with wasps, the nests can reach basketball size, with over 10 exterior layers and over 300 wasps inside.
That many wasps creates an excess of heat. As a result, the architecture of the nest becomes more sophisticated as it grows. The wasps build new tiers of cells for raising larvae, adding the additional tier underneath the previous one. Building the cells facing downwards lets them dry faster after construction. When the interior structure of cells grows too big for the exterior wall, the wasps chew away the innermost layer of the exterior and add another layer on the outer surface. The top of the nest has vents to let hot air escape upwards.
Like many, I feel a jolt of alarm when I see a yellowjacket nest larger than my head, boldly-colored wasps going to and fro. And it’s wise to give bald-faced hornets their space—their stings are painful even if you’re not allergic. But there are plenty of reasons for celebrating the presence of wasps. In many ecosystems, wasps are essential as checks on the populations of other species. Bald-faced hornets are voracious predators of biting flies as well as other yellowjacket species. There are many wasp species that specialize in eating a single species, such as the cicada killer, a solitary wasp that can definitely surprise you with its size when it buzzes past but has eyes only for its cicada prey which it paralyzes, drags to a burrow, and lays its eggs inside.
Big paper wasp nests in the fall are one of those little reminders that we don’t have perfect control over our environment, and what’s more, that it’s best when we don’t — when we can share space and allow other species to carry out their lives unencumbered, things all run a bit more smoothly.
Reading for Indigenous Peoples’ Day
Here are a few articles for reflection following Indigenous Peoples’ Day on Monday:
Meet the people saving Canada’s native grasslands: Despite a history of genocide, removal by force from many ancestral lands, and ongoing marginalization, Indigenous peoples in North America are leaders in conserving some of the most at-risk ecosystems on the planet. We’ve lost most of the grasslands on the continent to agriculture and sprawl. In Canada, Indigenous people are at the forefront of preserving and restoring grasslands, which are both vital ecosystems and also highly efficient at storing carbon, depositing it mostly in the soil (34% of the world’s carbon stock, on par with the 39% stored in forests, according to the WRI.)
Teaching the Hard History of Indigenous Slavery: This film, appropriate for classrooms grade six and up, addresses the history of colonial societies enslaving Native Americans in both South and North America. While its scope is broad, the beginning features Paula Peters, a journalist of the Wampanoag nation, which has ancestral lands in what’s now eastern Massachusetts and Rhode Island.
Native Knowledge: What Ecologists Are Learning from Indigenous People: Throughout the history of ecology and natural history, Western scientists have often tediously “replicated” things that Indigenous people have tried to tell them were already known and ignored other lessons learned over thousands of years. This year’s western fire season has driven home the gap between what Native Americans know about ecology and what’s practiced by governments. Researchers are now seeking to correct this imbalance through documenting Traditional Ecological Knowledge in projects that partner with Indigenous groups and treat their knowledge with equal value as data collected through other means.
Of course, many Indigenous people are academic scientists. This won’t be the last time I recommend reading Robin Wall Kimmerer’s Braiding Sweetgrass.
Learn whose ancestral lands you are on with this interactive map.
Flower of the week: Blue wood aster
Aster season continues with blue wood aster (Symphyotrichum cordifolium) which around my neighborhood occurs in the partial shade of tree-lined fences. The northern strains of the plant are cold-hardy and can keep their petals into November. The flowers are sometimes pale enough to appear white, and can be distinguished from white wood aster (Eurybia divaricata) by its more rounded clusters of flowers and later flowering times.
Here’s where the rubber hits the road for why plant diversity matters: a range of blooming times in a site’s flower species is essential for providing a steady source of nectar and pollen to bees, migrating monarchs, and other pollinator insects all the way until winter. While we humans are spending more time inside and may even be firing up the space heater, many pollinator insects are still out there making a living—and for some, preparing to overwinter, still a poorly understood part of their life cycle. Without plants like blue wood aster, fall would become pretty bleak for the bees.
Fall color isn’t just about trees
Matt writes in from New Brunswick, Canada, to share a sign of fall: the yellowing of Spartina cordgrass in the salt marshes.
Courtesy of Matt Mogle
A good reminder to keep an eye on my local salt marshes. Around this time of year, you can find red, tan, bright green and dark green all in the same marsh: a watercolor painter’s dream. In the Midwest and West, as we exit goldenrod season, little bluestem takes on a fiery copper tone and other grasses become shades of brown, with the green of cedars a sharp contrast. Plenty of fall color to see, even if you’re not in Vermont (strangely, I have never been to Vermont.)
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Possum Notes is a weekly newsletter about wildlife and landscapes around where I live. It’s produced on occupied Massachusett and Wampanoag land.