Dragonflies

The study of dragonflies

by admin - July 5th, 2013

The study of dragonflies, and sometimes damselflies, is called Odonatology. Dragonflies are referred to as Odonates.

Watching Dragonflies
Though watching odonates is easily done with the naked eye, a pair of close focusing binoculars will definitely make it easier. Though some species can easily be identified, some others need to be caught and closely examined in order to distinguish them from other similar looking species.

Most dragonflies prefer to perch themselves close to water, and the length of time they remain perched can vary. Various species tend to have individual behaviors, and you could have dragonflies that prefer hanging on twigs, or flying very high off the ground, making it quite difficult to observe.

Because of their compound eyes, dragonflies can see in many directions at once. This makes them very sensitive to movement, and some dragonflies can be quite easily startled. They don’t see very well from the rear, however – so if you plan to study one, it’s best approached quietly from behind.

band-winged-dragonlet-female-close

Identification
In order to properly identify odonates, you have to be familiar with the distinctive characteristics that can be found on the head, thorax, and abdomen of the dragonfly. This can be colors, shapes, or patterns. Roughly, the parts of a dragonfly are as follows:

1. Face
2. Eye
3. Occiput
4. Shoulder
5. Frontal thoracic stripes
6. Lateral thoracic stripes
7. Abdominal segments, of which there are ten
8. Cerci
9. Epiproct

One can look up the anatomy of a dragonfly in order to be able to distinguish it from a damselfly.

Size
Dragonflies can range in size from one inch to nearly six inches long. In order to identify one correctly, you have to make sure your size estimation is relatively accurate. This is easy if you have the dragonfly in hand. Otherwise, you can opt to measure them against something that can be measured, like a leaf that it was perched on, or your finger. Measuring the length of a dragonfly refers to the “nose” to the tip of its tail. The length of the wings are also measured, especially against the length of its abdomen.

Colour
It may seem like a no-brainer to determine what colour a dragonfly is, but bear in mind that there can be a lot of variations. Many species actually undergo changes in colour as they mature, as well as change as the temperature varies. Dragonflies are cold blooded, thus a dragonfly can become a darker colour in cooler weather, turning blue spots into purple or grey in cooler temperatures. Female dragonflies can also be coloured differently from the males, though most young males are coloured similarly to the females early in their life cycle. However, all dragonflies start out with hardly any colour, though some traces of their adult pattern may be visible. Some species, as they age, become pruinose – meaning they develop a bluish-white bloom that can cover their bodies and render their patterns obscure. Others can become darker, making their markings less distinctive.

How to control dragonflies

by admin - June 21st, 2013

Dragonflies are beautiful insects that belong to the order Odonata, along with damselflies. Dragonflies are predators that normally eat insects. They normally inhabit places near water – ponds, rivers, streams, and lakes – because their larvae, known as “nymphs,” are aquatic. Though adult dragonflies neither bite nor sting people, nymphs can sting at times. Though these stings are harmless, they can be relatively painful.

If for some reason, you would like to get rid of dragonflies in your home and yard, make sure that you have no water features around your home. Dragonfly nymphs, being aquatic in nature, need to have water in order to survive. So it you have a pond in your yard, you may want to consider getting rid of it altogether. If this is not an option, you can place fish in it, which will eat the dragonfly nymphs and eggs before they have the chance to reach adulthood. Frogs and toad eggs can also introduce diseases that will prevent dragonfly larvae from thriving properly.

You could also spray herbicide or pesticide in the area surrounding the pond, because polluted water will not be enticing to dragonflies. This will get rid of the nymphs, and potentially drive away the dragonflies because they will have no place for laying eggs. Pesticides will also get rid of the insects that dragonflies prey on, eliminating their food source.

Alternatively, you could allow floating plants to cover most of your pond. Because dragonflies are cold blooded insects, they need enough sunlight to survive. By allowing floating plants to grow and prevent sunlight from making its way into the pond, you will prevent dragonflies from breeding, eating, or escaping from predators.

If you want to get rid of the adult dragonflies, you will have to catch them with a net. You can then cut them in half and drop them into the pond in order to feed the other insects or small fish that reside there. You may have to repeat this process several times, and be ready – some dragonfly species are extremely quick and can soar to great heights.

Eliminating the dragonflies’ food source is the best way to get rid of them without having to catch them individually. Dragonflies normally prey on mosquitoes, gnats, and other small insects – if you are experiencing an overpopulation of dragonflies, it’s more than likely that your property has all of these other insects as well. If you get rid of these insects, the dragonflies will seek sustenance elsewhere. If you don’t get rid of the insects that serve as sustenance for the dragonflies, the population of mosquitoes and other insects will increase, and a new batch of dragonflies may come along after you get rid of the first one.

Of course, I’m a bit lazy, so I just contracted a pest control guy from this site to do the work for me.

Though it may seem like dragonflies can swarm, they normally don’t do this for over a week. Unless you live near a stream or ideal habitat for them, they will most likely move along before you know it.

Areas with high concentration of dragonflies

by admin - May 12th, 2013

The best place to look for dragonflies is in their natural habitat. A habitat will have to consist of several factors for it to be ideal, providing food and water, as well as space for various types of animals, plants and insects to interact and survive. Here are some of the types of habitat that dragonflies inhabit:

Rivers
Rivers are bigger than streams, and flows into a lake or ocean. When a river meets a flat expanse, the waters slow and spread out. This causes the silt to be deposited on the bottom. Where the river is slower and more sluggish, the water is nutrient-rich and warmer, making it more ideal for plant growth than upstream. The increased plant growth then provides more shelter for various types of insects, amphibians, and reptiles.

Some rivers are fast moving, while others are slow moving. Different types of dragonflies have preferences for either one.

Fast Rivers – Because the water in fast rivers move swiftly, organic materials don’t have the opportunity to accumulate. This in turn means that the food source is limited, and so is plant life. However, some dragonflies prefer this, like the Riverine Clubtail and Cobra Clubtail, and Stygian Shadowdragon.

Slow-moving River – The sluggish part of a river – where the rushing waters meet a flat expanse – is where the waters are nutrient-rich and the water is warmer. This makes it more conducive to plant growth, and in turn makes it a better food source for a variety of insects and amphibians. Dragonflies that prefer slow moving rivers with sandy bottoms are the Elusive Clubtail, Arrow clubtail, Skillet Clubtail, Common Sanddragon. Others prefer muddy bottoms, like Illinois River Cruiser and Prince Baskettail. Finally, some dragonflies prefer gravel bottoms like the Phygmy Snaketail.

Streams
Streams collect waste material such as dead leaves and rotting wood. This becomes the food source for various organisms, from bacteria to fungi. They form slime around leaves and rocks, and become the main food source of aquatic larvae.

Swift Streams – Because swift streams don’t allow organic materials to gather easily, there aren’t a lot of dragonflies that can be found around them. However, the ones that are attracted to swift streams are relatively uncommon, like snaketails.

Slow Streams – When fast streams mature, they turn into slow moving streams. Like those of rivers, slower streams are warmer and more-nutrient rich than fast streams. Many dragonflies enjoy the abundant food supply provided by this type of stream, like the Racket-tailed Emerald, Ski-tailed Emerald, Dot-tailed Whiteface and Ashy Clubtail.

stream

Still Water
Some dragonflies prefer to inhabit still water like ponds, lakes, bogs, and fence.

Lake – Natural or manmade lakes can be good habitats for dragonflies. Water plants usually are found near the shoreline since the middle might be too deep for rooted plants. Shallower lakes are richer in insects and algae, making it more ideal for dragonfly inhabitation.

Pond – Ponds are bodies of water shallow enough for plants to take root in them. They are usually home to Skimmers, which are a very large family of dragonflies, as well as Bluets and Forktails.

 

Plants which attract dragonflies

by admin - April 29th, 2013

If you want to attract dragonflies to your home, you’ll have to create a home for them too. A manmade pond is great for dragonflies, provided it’s well balanced and suitable for dragonflies in the egg and nymph stages. Make sure that your pond is a proper depth – not so deep that plants can’t take root in the center. Place flat rocks around it as well so dragonflies can perch on them. Your dragonfly pond should also be shielded from strong winds and gusts.

Aquatic plants, whether floating or submerged, can attract dragonflies. Different plants are suitable for different stages of a dragonfly’s life cycle.

Underwater Plants
Plants that are submerged can provide safety from dragonfly’s predators, making it necessary for a dragonfly pond. Dragonfly nymphs are vulnerable to predators, and these plants provide them with refuge, enabling them to make it to adulthood. One type of submerged plant that would be great for a dragonfly pond is the Dwarf Sagittaria, which is commonly found in ponds, lagoons, as well as freshwater streams. This ornamental plant can do well in zones 6 -10. Another option is the Brazilian Waterweed, which can survive zones 5 to 11.

Floating Plants
Floating plants don’t need to be able to take root in the pond. They are essential to your dragonfly pond however, because certain species of dragonfly lay eggs on the plants’ stems or undersides. Water lilies are an excellent option for water plants, and different types can survive in different areas. Just check which one is most appropriate for your climate.

Emergent Plants
Emergent plants are like submerged plants in the sense that they need to be rooted on the bottom of the pond. However, they are like floating plants because their stems and leaves emerge from the water. Emergent plants are an essential feature of dragonfly ponds because dragonfly larvae use them to get to the pond surface when they reach adulthood.

Shoreline Plants
Marsh plants, also known as shoreline plants, are used by adult dragonflies for perching, as well as egg-laying. These hydrophilic plants do best in damp, moist soil. Examples of these are cattails, Arrowhead, Water Lilies, and Blue Flag.

You should place your pond in an area that gets full sun because dragonflies are cold blooded. This will also allow sunlight to make its way to the aquatic life below. Make sure to prevent the floating plants from covering most of the pond’s surface as well to allow sunlight to go through.

When creating your dragonfly pond, make sure not to put any fish in them. Though fish are a lovely addition to a pond, they eat dragonfly nymphs. Avoid using pesticides or herbicides around your pond as well, as this might kill dragonfly nymphs – and dragonflies will end up avoiding the pond because of the tainted water. Also, don’t mow the area around your dragonfly pond. Allow the plants to become well established so they can serve as perching places for the dragonflies.

Different Types of Dragonflies

by admin - February 8th, 2013

Dragonflies belong to the order Odonata, along with damselflies. Dragonflies are known as Anisoptera, while damselflies are known as Zygoptera.

Dragonfly Families

Skimmers
The dragonflies belonging to the libellulidae family are the skimmers and perchers. They can be found in nearly all areas inhabitable by dragonflies in North America, though not the extreme north areas like Alaska and Canada. This is one of the most diverse families, and thus there is no one type of body that exemplifies it. Libellulidae does have several types of genus that fall under it:

  • Erythemis – found mostly in the topics, they have a slender and triangular abdomen. They have long spines on the front of the legs.
  • Leucorrhinia – small, with slender abdomens, these types are mostly black in color with red markings. Most species can be found at high elevations.
  • Libellula – these dragonflies have thick abdomens and are usually large to medium-sized. While most species are brown or black with yellow markings, adult males turn a powdery pale blue.
  • Pachidyplax – only one species belongs to this genus. Though similar to Erythemis, they are smaller and have a striped thorax. The larvae’s undersides are bright green.
  • Pantala – dragonflies of this gees have large, triangular hind wings. Both sets of wings – forewings and hindwings – are large in proportion to their bodies. They are normally colored orange to brown. They can travel long distances and can store fat in their abdomens in order to sustain them throughout their migrations.
  • Sympetrum – except for the black meadowhawk, dragonflies belonging to this genus are generally colord red. They are small and have slender abdomens.
  • Tramea – these dragonflies have large, triangular hind wings, which are long in relation to their bodies. They are commonly called saddlebags because they have markings on their bases which resemble saddlebags.

Darners
Darners are among the largest types of dragonflies that can be found, ranging between 2.5 – 5 inches in length. Their thorax is robust, and have large compound eyes which cover most of the head. They normally have long and slender abdomens patterned with blue, green, or yellow. They can usually be seen in swarms during late summer. They are strong and fast fliers, capable of reaching great heights. Because they have a highly developed nervous system, they actually can control their body temperature to a degree. This allows them to fly in colder temperatures compared to other dragonflies.

Petaltails

Petaltails are shaped like Darners. However, unlike Darners, their eyes are separated and have long and narrow stignas. They are believed to have existed for more than three hundred million years, making them the oldest of all flying insects.

Clubtails

Clubtails have wider abdominal segments 7-9, hence their name. However, not all clubtails possess this quality, while some non-clubtails do. They range in size from 1.5 to more than 3 inches long, and have widely separated eyes which are normally either green or blue. Their thorax and abdomen have a distinct yellow, gray or green pattern. Males and females are similar in coloration, but females usually have a stockier abdomen and more extensive yellow markings.