A blue bell dragonfly alights on a plant. Dragonflies have eyes that sit close together on top of their heads; damselflies have eyes separated on each side of their heads. / Missouri Department of Conservation
The black-winged damselfly is harmless to humans. / Getty Images/Brand X
The Hine's emerald dragonfly is the only species on a federal list of endangered insects. / Missouri Department of Conservation
If you spend time at a lake, stream or any other body of water, you’ll see them: Slender insects flying or hovering inches above the water until they land on a solid surface, sit motionless, then return to zigzag along the water’s surface.
These dragonflies and damselflies are common in Missouri. Anyone who swims can be the surface on which these harmless insects land.
The two types of insects are similar. They both belong to the order Odonata, both share similar habitats, have similar diets and behaviors, and while they do have similar appearances, there are a few important differences pointed out elsewhere on this page.
Dragonflies and damselflies are the adult, more highly visible versions of insects that spend most of their lives in water as larvae called naiads. The naiads hunt for small aquatic animals by resting at the bottom of the water and then using extendable jaws to snatch food. After spending as long as five years as a nymph, and after shedding its skin several times, the larva crawls onto the surface, sheds its skin one last time and emerges as a dragonfly or damselfly. As an adult, the insect mates and produces eggs that will become a new generation of naiads.
Dragonflies and damselflies are often seen as beneficial because, as adults, they eat mosquitoes. Both insects hunt with a method known as “hawking.” They fly with their legs held in a basket shape to grasp mosquitoes and other small flying insects, especially flies.
In hunting, they benefit from truly skilled flying. They can even fly backward.
Rare dragonfly lives here
Dragonflies and damselflies are easy to find in Missouri, and dozens of species call the state home. However, nine of the state’s species of dragonflies and six species of damselflies are considered species of conservation concern, meaning their numbers could vanish from the state some day.
Among these is the Hine’s emerald dragonfly, which is endangered both at the state and national level. It is the only species that is on federal list of endangered insects. It is extremely rare. Outside of a few counties in south-central Missouri, this dragonfly is found in Door County, Wis., and in small sites in northern Michigan and northeastern Illinois.
Information for this story came from the Missouri Department of Conservation
Dragon or damsel
Dragon or damsel
Dragonflies and damselflies are so similar, many people just think of both as dragonflies. There are a few differences, however, and here are some:
• Damselflies have longer, more slender bodies than dragonflies.
• Dragonflies have eyes that sit close together on top of their heads, whereas damselflies have eyes that are clearly separated on each side of the head.
• Dragonflies have dissimilar wing pairs, while damselflies have wings with similar shapes.
• At rest, dragonflies hold their wings out to the side. Damselflies hold them up.
• As nymphs, dragonflies have internal gills for breathing, whereas damselflies have external gills.
Source: Missouri Department of Conservation
• Dragonflies can fly forward at about 100 body lengths per second, and backward at about three body lengths per second. They are also capable of hovering in the air for about a minute.
• The Odonata are known to be ancient insects. The oldest recognizable fossils of the group belong to the Protodonata, an ancestral group now extinct. The earliest fossils so far discovered come from Upper Carboniferous (Pennsylvanian) sediments in Europe formed about 325 million years ago. Like modern-day dragonflies, the Protodonata were fast-flying with spiny legs that may have assisted in capturing prey; their wingspan was as long as 30 inches. The group became extinct in the Triassic period, about the time that dinosaurs began to appear.
• Though dragonflies are predators, they must be wary of many predators. Birds, lizards, frogs, spiders, fish, water bugs and even other large dragonflies all eat odonates. However, dragonflies have many adaptations to protect them, such as exceptional visual responses and truly agile flight.
Next week: NIE takes a look at bees.