Goldenrod Exploration

goldenrod patch

Goldenrod: An Exploration.

The rods of gold are aptly named, for a richer environment would be hard to find. Well-populated with inhabitants of all colors and sizes, goldenrod is the community center of the plant world. If you are, for instance, a wasp or a bee or a fly, it is the place to see and be seen. On the other hand, if you happen to be a spider, lurking in the shadows would serve you well. Every lodger has a reason for being there, a niche to occupy.

By the Numbers

There are over 100 species of goldenrod in the United States, most of them native. About two dozen can be found in the mid-Atlantic region, with some blooming as early as July while others are still in bloom in late October. With its extended bloom season, it is no surprise that goldenrod attracts a wide range of insects and spiders. Gall makers—mostly midges, flies and moths—lay their eggs on stems and leaves giving rise to swellings and clumpy rosettes that draw, in turn, parasitic wasps, beetles, and other predators. A New York researcher documented 138 species of insects that fed on the foliage of tall goldenrod (Solidago altissima), many of them goldenrod specialists; a Penn State study identified goldenrod as a top pollinator attractant, second only to mountain mint (Pycnanthemum muticum).  In an Illinois count, more than 90 kinds of bees alone were spotted on Canada goldenrod (Solidago canadensis). Wasps, flies, moths, butterflies, and beetles also frequent the showy flowers, and on a micro level, these pollinators alter the microbial community that lives on the blooms.

honey bee on goldenrodConnections

What connections do all these visitors have to the goldenrod plant itself, to other plants in the surrounding environment, and to each other? Just by investigating the questions, we become immersed in a powerful ecological community that very possibly touches on every aspect of our local environment. The explorations hint at the complexities of life. They hold great power: that of transforming misconceptions, fear, and loathing into fascination.

First Up

pollinator goldenrod soldier beetleis a beetle familiar to many nature observers: the goldenrod soldier beetle (Chauliognathus pennsylvanicus). The first beetle of its type to be discovered wore colors similar to British soldiers, thus the name. It’s also known as Pennsylvania leatherwing.

These firefly relatives don’t emerge until late July—coincidentally, just when goldenrod begins to bloom—and only hang around for two months or so. The adults feed mainly on pollen and nectar, although they are equipped to take out soft-bodied insects, such as aphids. They favor goldenrod flowers but you’ll also find them feeding on coneflowers, tansy, helianthus, and lots of other blooms. Often you’ll see them mating on the flowers. The females lay eggs in the soil or in leaf litter, and soon afterwards the larvae emerge. As with many familiar insects, it’s the larvae that earn the soldier beetle the “beneficial” tag by feeding voraciously on the eggs and larvae of beetles, grasshoppers, moths and other insects. In the lab they’ve been shown to be predators of tick larvae and nymphs!

soldier beetle 2The downside of being a denizen of late summer is that the cool moist conditions that sometimes occur favor a fungal pathogen called Entomophthora lampyridarum, which actually alters the insect’s behavior. Infected soldier beetles travel to the upper leaves of a plant and die attached to a leaf with their wings spread, fungal spores erupting from their bodies into the air. Although this does not end well for this particular generation of soldier beetles, this mode of infection is, in general, a good thing, in that it keeps insect populations in check. Gypsy moths, locusts, and other pests suffer similar sporadic fates in unlucky years. In fact, some entomologists believe that fungi act as primary regulatory agents of insect outbreaks.

Next up: the Goldenrod leaf miner

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