Dragonflies are sometimes colloquially called devil's darning needles, thus no differences exist between the two as they're one and the same. Roughly 3,600 dragonfly species are found across the globe, all belonging to the taxonomic family Anisoptera. Although these species all have their own characteristics, they're also similar in certain ways.
Adult dragonflies have long, thin, needle-like bodies, which is why they're sometimes referred to as devil's darning needles. All species have six legs, two pairs of wings, disproportionately large eyes, short thoraxes and long abdomens that are split into 10 segments. They're generally bright and colorful, although exact colors and patterns vary between species. The largest known dragonfly species has a wingspan of up to 6.3 inches, whereas the smallest has a wingspan of roughly 1.3 inches.
Range and Habitat
While dragonflies are found anywhere across the globe -- excluding polar regions -- the largest number of species are located in tropical areas. They live in many different areas and habitats. However, one essential factor is they must live near freshwater, as they lay their eggs in or near water and their larvae -- or nymphs -- are aquatic creatures. Depending on the species, they inhabit areas around different types of water sources, including rivers, streams, lakes, swamps, marshes and dikes. They may fly several miles away to hunt for prey, but most of their time is spent near open water.
Adult dragonflies are active hunters, meaning they chase and capture their prey, rather than waiting for it to come to them. Their six legs act as nets to help them capture their dinner. They primarily eat flying insects, such as mosquitoes, aphids, flies, moths, bees and other dragonflies. The type of prey they go for depends on the size of the species. Dragonfly nymphs are fully aquatic and live mostly on insects that live in water. Their modified, hinged lower lips -- known as facial masks -- help them catch their prey.
Reproduction and Development
Breeding season for dragonflies is in spring or summer, not long after they enter their adult stage. Some species are territorial, and males will defend a prime egg-laying area, whereas other species are happy to share territories. Males and females practice internal fertilization, with males depositing their sperm into females' sperm storage organs. Females then lay their eggs either in or near the water, depending on their species. When they hatch out, baby dragonflies are known as nymphs. These nymphs are aquatic creatures with stout bodies and six legs that look quite different from their adult counterparts. Different types of dragonflies take varying amounts of time to reach adulthood -- anywhere from a few months to a few years.