Dragonflies are fascinating insects that have been around for over 300 million years. There are over 5,000 species of dragonflies found all over the world, except Antarctica. Dragonflies come in a stunning array of colors and patterns on their wings. Some species have wings that are partially or fully black in color. In particular, there is one group of dragonflies that has become known for their distinctive black and colored wing patterns. These are the skimmers, a family of dragonflies known as Libellulidae. Within this family, several species have wings that are half black. Let’s take a closer look at these fascinating dragonflies with bicolored wings.
Skimmers with Partially Black Wings
Skimmers are medium to large sized dragonflies that are incredibly agile fliers. They are named for their skill at skimming over water to hunt other insects. Several types of skimmers have wings that are partially black at the base or tip. Here are a few examples:
– The widow skimmer has black patches at the base of its wings. The rest of the wing is whitish with black veins.
– The ebony jewelwing has black wings with iridescent green, blue, or purple markings on the tip.
– Some male twelve-spotted skimmers have black tips on their forewings and hindwings.
While stunning, none of these skimmers have wings that are fully half black. There is one particular species, however, that does meet this distinctive criteria.
The Banded Skimmer
The banded skimmer (Erythrodiplax umbrata) is a tropical species of dragonfly found in Central and South America. As its name suggests, it has very striking banded wings. The top half of its wings are black, while the bottom half are clear or orange-brown in color. This gives the appearance of wearing “bands” when its wings are open.
Here are some more details on this uniquely-patterned skimmer:
| Scientific Name | Erythrodiplax umbrata |
| Family | Libellulidae (skimmers) |
| Size | 1.7 inches (45 mm) long |
| Range | Central and South America |
| Habitat | Tropical forests, marshes, ponds |
| Wing Color | Top half black, bottom half translucent orange-brown |
As you can see, the banded skimmer perfectly matches the description of having half black wings. When it is flying, the black and lighter portions create a defined banded pattern, unlike other skimmers that may just have black patches or tips.
Reasons for the Bicolored Wings
So why does the banded skimmer have such remarkably different colored panels on its wings? Entomologists aren’t exactly sure, but there are some leading theories.
One possibility is that the wing pattern helps regulate body temperature. The black sections may absorb more heat, while the translucent sections allow heat dissipation. This could help the dragonfly stay warm in cooler forest areas but prevent overheating in the tropical environment.
Another theory is that the conspicuous black and orange-brown pattern acts as a warning signal. The bold contrast may warn predators that the dragonfly could be distasteful or toxic. Many insects use this type of aposematic coloration as a defensive strategy.
There could also be a role in mate selection and territorial displays. The low contrast orange-brown sections may glow brightly in sunlight, making the wings more visible. This could help males stake out territories and impress potential mates.
More research is needed to determine the advantages the banded skimmer gains from its uniquely half black wings. Likely it is a combination of functions related to thermoregulation, predator evasion, and reproductive success.
Differences Between Males and Females
There is some slight sexual dimorphism between male and female banded skimmers. Males tend to have more extensive black coloration on their wings. The black area may take up nearly two-thirds of the wing surface. Females have relatively smaller black sections, usually limited to the top third of the wing.
Males also develop a powdery blue or pruinose coating on parts of their body as they mature. This includes the thorax, abdomen, and legs. The blue coloring is thought to have a role in mate attraction. Females lack this temporary pruinosity.
Otherwise, the sexes are similar in size, body shape, and wing patterning. Both feature the distinctive banded wings with black on top and clearer sections below.
Habits and Habitats
The banded skimmer lives in tropical regions from Mexico down through Central America into South America. Their habitat includes rainforests, marshes, ponds, and other wetlands.
Skimmers get their name from the way they hunt. They fly over water and use their legs like a basket to scoop up insects and small fish. The banded skimmer likely uses its maneuverable half black wings to swiftly snatch prey while darting and hovering over the water surface.
Very little is known about the reproductive behavior of these tropical dragonflies. Males likely use their bold wing patterns to defend breeding territories. Females lay their eggs in vegetation near water. As larvae, the young skimmers will develop underwater as voracious predators.
Adult banded skimmers likely play an important role as aerial predators that help regulate mosquito and other insect populations in tropical wetland systems. Their larvae also help cycle nutrients and serve as food for fish and other aquatic life.
Unusual Appearance
With its remarkably split black and lighter-colored wing pattern, the banded skimmer certainly stands out among its dragonfly peers. No other species has such an even bisecting line separating the top and bottom wing surfaces. This makes the banded skimmer unique among the 5,000+ types of dragonflies worldwide.
Of course, many other dragonfly species have some black coloration on their wings. But the banded skimmer exemplifies a dragonfly with precisely half of its wings black in color. This strange and striking appearance has made the banded skimmer a favorite among insect enthusiasts.
There is still much to learn about this charismatic tropical species. Future studies of its natural history, thermoregulation, mate selection, and other behaviors could give more insight into why it has evolved such an unusual wing pattern. For now, we can simply appreciate the banded skimmer for its distinctive good looks!
Conclusion
Dragonflies display a stunning diversity of wing colors and patterns. Among this variety, the banded skimmer stands out for having perfectly bisected wings – half black on top and lighter below. This tropical American species in the family Libellulidae is the only dragonfly that precisely meets the description of having half black wings. While the reasons behind its bicolored wings remain uncertain, possible advantages include better thermoregulation, predator avoidance, and visual displays for mate selection. With its striking appearance, the banded skimmer showcases the wonderful creativity of natural selection. The next time you see a dragonfly, take a closer look at the wings – you just might spot a banded skimmer!
