Dragonflies

Having emerged, the adult dragonfly must cling to the plant stem for about two hours, during which time the body and wings harden in readiness for flight. The adult dragonfly emerges from the larval skin (which remains clinging to the plant stem). The order of insects to which dragonflies belong (Odonata) is divided into two sub-orders.

The first of these (Anisoptera) includes the large, fast-flying dragonflies while the second (Zygoptera) covers the smaller, slower-flying damselflies. Dragonflies are the world's fastest insects, capable of reaching speeds of up to 60 mph. The Common Green Damer dragonfly ( Anax junius) is nicknamed "Darner Needle" because of its body shape. It is one of the biggest and fastest-flying dragonflies, able to reach speeds of 53 mph (85 km/h).

Found only in the wet and moist forests in Central and South America is the Megaloprepus caerulatus damselfly. It has the greatest wingspan of any living damselfly or dragonfly but remember it is not a dragonfly. The wingspan grows up to 19 centimeters (7.5 inches) in the largest males. Its large size and the markings on its wings make it a conspicuous species; a hovering Megaloprepus has been described as a "pulsating blue-and-white beacon".

Dragonflies may exist as larvae, or nymphs, from a few months up to five years, depending on the species. During this stage they live entirely under water, mostly in ponds, lakes and canals. The dragonfly's adult life lasts for little more than one month.

Dragonflies are fast-flying, four-winged insects with long bodies and enormous eyes. The adult dragonfly has the biggest eyes in the insect world and they are capable of detecting movement up to 15m away! They have up to 30,000 facets to their compound eyes; each one is a separate light-sensing organ, arranged to give nearly a 360 degree field of vision. These fascinating and colorful creatures are among the fastest and oldest insects in the world. Their fossilized remains show that they were already here on earth 300 million years ago! For these reasons only the dragonflies are well worth studying and protecting.

All dragonflies are carnivorous in both the larval and adult stages of their lives. They feed on insect larvae and other smaller water dwellers up to the size of a large tadpole during the larval stage, and then graduate to most flying insects as adults.

Dragonflies may exist as larvae, or nymphs, from a few months up to five years, depending on the species. During this stage they live entirely under water, mostly in ponds, lakes and canals. The dragonfly's adult life lasts for little more than one month.

Male dragonflies have their own territory; they guard their particular stretch of water seeking prey, females and chasing off rivals.

There are two groups of dragonflies; one is known as hawkers: these have long, slim bodies and patrol up and down stretches of water, 'hawking' for prey. When they rest they hold their wings out, either horizontally or slightly forward. The other group is known as darters: these have smaller, fatter bodies than hawkers, the eyes of a damlesfly are separated, while those of a dragonfly are nearly touching, and spend most of their time clinging to waterside plants, occasionally darting out to catch a passing insect. When they rest they hold their wings together above the body.

Dragonflies in Danger

Fifty years ago there were twice as many ponds as there are today. The draining of agricultural land, filling in and pollution have all contributed to the disappearance of most countryside ponds. Canals have also suffered from pollution, especially by chemicals used on farmland draining into water. The loss of suitable fresh water habitats has affected dragonflies enormously and they are becoming increasingly rare.

Last but not least is the world's smallest dragonfly seen at the left. Normally found in eastern Asia, according to some entomologists from the Metropolitan Museum of Natural History that I took on tour, they pointed out several to me here in Rio Dulce. It has a total length of approximately 15mm (0.6 inches) and a wing span of only about 20mm (0.8 inches).