This week in the woods, messes of flowers – American-asters, goldenrods, and more – give the last, late blooms of summer and feed bees, butterflies, and other insects still flying. With a majority of other flowers having come and gone, these species monopolize pollinators’ attention – and have a brief window for fertilization and setting seed before killing frosts come. A number of American-asters (members of the Symphyotrichum genus once commonly known as asters) have adaptations to avoid damage from the cold, sustain blossoms longer, and increase chances of reproduction. Species like the purple-stemmed American-aster (or swamp aster) have trichomes, or short gland hairs, that hold moisture and prevent frost from reaching parts of the plant. In another case, the lance-leaved American-aster (or panicled aster) exhibits a kind of movement known as nyctinasty, wherein their blossoms open and close in response to light and temperature change.
Migration for dragonflies, like a number of species in the Aeshna (mosaic darner) genus (photo by Ann Little), runs from July to mid-October, with its peak during this month. As Madeline Bodin explains in this archival The Outside Story article, individuals that take migratory flights south in the fall do not also fly north in the spring; rather, the process takes multiple generations to complete, like monarch migration. The journey also shares much with that for migrating raptors, like broad-winged hawks, also peaking in September. A great deal of data on dragonfly migration even comes from hawk watchers observing them riding the same thermals and tailwinds. “Both hawks and dragonflies are driven by cold fronts in the fall,” writes Madeline Bodin. “Both take advantage of air currents and ridgelines. And both tend to cluster in large groups before their migration route passes over a large body of water.”
What have you noticed in the woods this week? Submit a recent photo for possible inclusion in our monthly online Reader Photo Gallery.