Your Land & Water for July 2026

jhansen49
Jul 11
7 min read

What's in this issue? A deep dive into the world of dragonflies and damselflies! These aerial acrobats make tremendous friends around our waterways. Read on about the differences and fascinating lives of these insects.

DRAGONFLIES AND DAMSELFLIES

One of the delights of summer is watching dragonflies hovering over a pond or stream as they hunt. They are among our most beautiful insects with their delicate wings and iridescent bodies. They are also among the best fliers in the animal kingdom with their ability to hover, fly forward and backward, and eat and mate in flight. Their wings are independent of each other which enables great maneuverability, and they have huge eyes that can see 360° around them.

Dragonflies and damselflies are both in the order Odonato, which means “toothed one” in Greek, referring to their toothed mouth parts (mandibles). Dragonflies are generally larger and heavier-bodied while damselflies are smaller and more petite. Dragonflies also hold their wings outspread when they perch, while damselflies hold their wings together (except for one small group that hold their wings partially open).

https://www.farmersalmanac.com/wp-content/uploads/2020/11/dragonfly-vs-damselfly.png

Around 3,000 described dragonfly species inhabit every continent except Antarctica, with the heaviest concentration in tropical and subtropical regions. In North America alone, roughly 350 species have been documented. New Jersey, which is the 3rd smallest state by area, ranks 4th for the longest list of dragonfly & damselfly species of any state, behind Texas, Virginia, and New York.

Dragonflies and damselflies occupy a considerable variety of habitats, but many species, and some families, have their own specific environmental requirements. Some species prefer flowing waters, while others prefer standing water. Adults may require emergent or waterside plants to use as perches; others may need specific submerged or floating plants on which to lay eggs. The chemistry of the water, including its trophic status (degree of enrichment with nutrients) and pH can also affect its use by dragonflies. Most species need moderate conditions, not too eutrophic (well-nourished), and not too acidic.

Dragonflies and damselflies (Odonates) are terrifying hunters. Both typically consume up to 95% of the prey they chase. In a single day, a dragonfly may eat an amount of prey equal to about one-fifth of its body weight and can consume 30 to hundreds of mosquitoes per day.

The Odonates are powerful and agile fliers, capable of moving in any direction, and changing direction suddenly. In flight, the adult dragonfly can propel itself in six directions: upward, downward, forward, backward, to left and to right. In general, large dragonflies like the hawkers have a maximum speed of 22–34 mph (36-54 km/h) with an average cruising speed of about 9.9 mph (16 km/h).

Young Dragonflies and Damselflies

Dragonfly and damselfly young, called larvae or nymphs, are aquatic predators. The nymphs are as dedicated predators under water as the adults are in the air. They consume mosquito larvae, worms, crustaceans, tadpoles, and small fish.

The nymphs have bulging eyes somewhat like the adults but possess a formidable anatomical structure that is not present in the adult. Called the “mask,” it is a fusion of the larva’s third pair of mouthparts. Quite large, the mask folds beneath both the head and thorax when it is not in use. At the end of the mask is a set of fanglike pincers used to seize prey.

Illustration of "the mask" found on dragonfly larvae.

Most of a dragonfly's life is spent as a nymph, beneath the water's surface. In some (larger) species, the nymphal stage lasts up to five years, and the adult stage may be as long as 10 weeks, but most species have an adult lifespan of five weeks or less, and some survive for only a few days.

The larvae of different species have different requirements for the depth and quality of the water, and how fast it moves, among other characteristics. A sample of the species present can tell ecologists a lot about the ecosystem they’re looking at. Consequently, dragonflies and damselflies serve as “indicator “species“ – organisms whose presence, absence, or abundance serves as a measure of ecological health. For example, dragonfly nymphs are more tolerant of some pollution in water while damselflies are less so and their populations will drop out or be less abundant as the water quality decreases.

The Odonates have been around for 300 million years. They are among the oldest insects on earth, existing 100 million years before dinosaurs. Fossils indicate that some were super large, such as Meganeuropsis permiana, having a wingspan of over 2 feet, compared to those living today which typically span only 2 to 5 inches.

https://animalcorner.org/dragonfly-anatomy/

Reproduction

The males of most dragonflies and damselflies are highly territorial, patrolling an area that has either an abundance of prey food or good vegetation for egg-laying, or both. For most species, a female will not mate with a male unless he has a territory.

During courtship, many male odonate species behave similarly to birds, chasing away other males, guarding the female, and doing courtship displays. The stunning damselfly, the Ebony Jewelwing, for example, will attempt to attract a female by performing what’s known as a “cross” display. It faces the female and then turns its hindwings downward, keeping them perpendicular to the body. Then it raises its forewings and abdomen, displaying the pale underside.

When they mate, the male dragonfly/damselfly grasps the female behind her head with pincers on his tail. She then curves her long abdomen under and upward to the genitalia on segments 2-3 of his abdomen where she can pick up the packet of sperm. This distinctive position is known as the “heart” or “wheel.”

White-legged damselflies (male is blue, female is greenish white) forming a “heart.” Livescience.com

The male and female fly in tandem to an area with vegetation that might be good for egg-laying. For some species, the male will not let go until the eggs are laid, ensuring that the female will not mate with another male before depositing her eggs within a plant stem or, in some cases, on the water. This behavior following the transfer of sperm is termed as “mate guarding,” with the guarding male attempting to increase the probability of his sperm fertilizing the eggs. Flying in tandem has the advantage that less effort is needed by the female for flight, and more can be expended on egg-laying, and when the female submerges to deposit eggs the male may help to pull her out of the water.

Migration

Some dragonfly species are migratory. For instance, the globe skimmer (Pantala flavescens) undertakes an annual journey, with each individual traveling over 6,000 km (3,730 miles), from India to Africa, one of the longest known migrations among insects.

Migration normally occurs in August and September. Two groups of dragonflies are migrators in North America—the darners and the skimmers—and 16 species make up these groups. In the adult form most dragonflies live for only two to four weeks, while migrating species may live for a few months.

Scientists have attached miniature transmitters to green darners and discovered that darners from New Jersey traveled every third day, averaging 7.5 miles. One individual logged 100 miles in one day. Some migratory species travel in swarms that can be quite enormous. Fortunately, dragonflies don’t bite people unless they are grabbed and feel threatened.

"Common Green Darner (Anax junius)" by sankax is licensed under CC BY-NC 2.0.

Green Darners are abundant dragonflies in New Jersey. A Common Green Darner migration is complex and challenging to study. Researchers now suspect a full migration takes place over at least three generations. The first generation emerges in spring in the southern part of the range and travels north in the summer. The second generation emerges in the northern part of their range in summer and migrates south during the fall. The third generation emerges in the southern part of the range during the winter and doesn’t migrate. Then the cycle begins again with the next generation.

Conservation

Habitat degradation has reduced dragonfly populations across the world. The dragonfly's long lifespan and low population density makes it vulnerable to disturbance, such as from collisions with vehicles on roads near wetlands. Species that fly low and slow are more at risk.

The majority of species live in tropical areas and have been little studied. With the destruction of rainforest habitats, many of these species are in danger of becoming extinct before they have even been named. The greatest cause of decline is forest clearance with the consequent drying up of streams and pools which become clogged with silt. Loss of habitat in general, the damming of rivers for hydroelectric use, and the drainage of low-lying land has reduced suitable places for odonates, as have pollution and pesticide use.

New Jersey Species

Dragonflies are abundant across New Jersey, with over 100 species recorded in the state, although 33 of these species are on the state’s threatened and endangered species list. These aerial hunters are easiest to identify by focusing on three markers: body color (green, blue, red, brown, or yellow), wing patterns (solid, banded, or spotted), and size (from 1 inch to 3+ inches). Most sightings occur from late May through August, with peak diversity in July and early August. The most commonly encountered species are the Common Green Darner (large, green), Eastern Pondhawk (green females, blue males), Blue Dasher (small, white face), and Widow Skimmer (white wing bands).