Given a flatter rock, it would’ve been effortless to fade off into the blissful stupor of a midday, summertime nap, riverside. Without one, it was as close to a dream as I can have, waking. The crystal clear water of the James River flowed swiftly by the warm gravel bar I was sitting on, ripe with oxygen after spilling over three miles of ledges and splitting into a maze of rivulets. A dip in the river thinned the dense weight of August in the Piedmont. The smallmouth were hungry, as evidenced partly by my level of supreme afternoon contentment, and partly by the scene transpiring in the riffle downstream.
A wispy cloud of blue swarmed above the tumbling water. A pack of young, hungry smallmouth made their presence feeding in the shallow riffle known by launching themselves from the water, two feet into the air, and closing their jaws on the small stipples of blue. These blue damselflies are riparian residents of summer as native as the sun and the stargrass waving in the riffle, and though the smallmouth, themselves, aren’t native, if there’s a visual definition of summertime in Virginia, to me, it’s the one that was playing out right in front of me.
Species Galore
The blue damselflies of our state’s warmwater waterways are of the family Coenagrionidae—the narrow-winged damselflies. They are a small, slender, and dainty flying insect that have clear wings that they hold vertically over their body at rest, which distinguishes them easily from the dragonflies, which hold their wings horizontally.
Coenagrionidae is represented in the Old Dominion by six genera and 36 species. The various species of the genera Argia and Enallagma make up what we commonly see and call blue damselflies, and it’s the latter genus, commonly called the bluets, that is the most common, accounting for about a third of the damselfly species in our state. Members of the former, Argia, are commonly called dancers, and can be distinguished from the bluets primarily by their namesake bouncy, jerky flight pattern.
Life of a Damselfly
Damselflies have a one-year life cycle. The nymphs are aquatic, long and slender, resembling small, wingless adults with the addition of three leaf-like appendages extending from the end of their abdomens that serve as gills. Nymphs spend most of their time stationary, and are ambush predators, using their large, swift, extendable lower jaw to grab passing prey. These nymphs are born in the fall, and mature through the winter and spring, molting several times.
In late-spring or early-summer, the nymphs exit the water via emergent vegetation (usually willow grass beds on our rivers) and emerge into adults. They then fly off to nearby vegetation to feed and mature further.
Mature adults spend most all of their time feeding on flying insects and searching for mates. If you’ve spent any time on a river observing damselflies, you’ve likely witnessed mating behavior. Males will fasten the small appendages at the end of their abdomen to the female just behind her head. If the female is receptive, she’ll allow the male to grasp her, and she’ll curl her abdomen around to attach to the male’s secondary sexual organs, called hamules, at the base of his abdomen. The female will then use her ovipositor to slice a hole in emergent grass shoots and deposit the fertilized eggs. Often times, the male will remain attached to the female’s head as she does this, guarding his mate in the tandem flight formation that many are familiar with.
Smallmouth in Distress
Damselflies have a relatively short life span—usually just a few weeks long. And during that time, they must evade predators from above (birds) and below (smallmouth). Unfortunately, recent generations of damselflies have had less to worry about from below.
The numbers of smallmouth bass in our river populations have been largely declining in recent years, thanks largely to poor spawning success, due almost entirely to unfavorable streamflows in April and May. In 2020, the James River sustained five flooding events during the bulk of the smallmouth spawn, between April 10 and May 31, and as a result, very few juveniles were successfully spawned. In 2018, there were five flooding events in the same time period. In 2017, there were four. In 2015 and 2016, there were fewer, but floods just after egg-laying resulted in poor to fair spawning success, too.
All ages of smallmouth feed on damselflies, but while the young fish will leap wildly from the water attempting to intercept their flight, the older, slower, and more cautious specimens are more subtle. Because of poor spawning success in recent years, numbers of young, one- to five-year-old (0- to 12-inch) smallmouth are abysmal in most of our rivers, and the entrancing scene that played out every summer in the riffles of my home river is relatively absent. It’s one of my greatest hopes that it will return, someday soon.
*Originally published in The Rural Virginian