Most people know that there are blue ones and red ones, but the array of dragonflies to be found is much, much wider. Have you joined the fan club yet? By Warwick Tarboton
Some are multi-coloured, others are shimmering green, or black and yellow, or mottled in shades of ochre and tan. Dragonflies need little introduction, being as familiar a group of insects as bees, flies, butterflies or beetles. But did you know that in South Africa there are 164 species, all with strikingly patterned wings, delicately coloured faces or brightly coloured tips to their abdomens? There are species so large that, at a glance, they could be mistaken for a small swallow as they skim across the water, and species so tiny, less than 20 mm in length, they are easily overlooked in their habitat of dense emergent grass.
Like birdwatching, watching and photographing odonata, as dragonflies and damselflies are collectively known, is becoming increasingly popular. This is because they can be found on virtually any water body, even on seeps and dams in the driest parts of the Karoo. They are easy to observe, mostly not difficult to identify using close-focusing binoculars and have interesting behaviours and life histories. They are very photogenic, too. There are other advantages, not least that they operate only during the warmer hours of the day, so you don’t have to get up before dawn to find and watch them. And, unlike birds, there are no calls to learn.
These insects share numerous characteristics with birds though. Many are supreme fliers, capable of speeds of 35 km/h in direct flight, with superb manoeuvrability and the ability to hover, climb vertically and turn on a tickey. All the species are predatory, hunting and eating other smaller insects, which are pursued and caught in flight in the way a sparrowhawk hunts its prey. Several species are migratory and there is growing evidence that one of the common species, the Pantala sp., even commutes annually between India and Africa.
Many species are territorial, others lead mostly solitary lives, and a handful are highly gregarious. Territoriality is confined to males and mostly to the perching species in which males return daily to selected positions over water. These sites are aggressively defended from other males, while visiting females are lured here to mate.
One summer my wife and I gained an insight into this territoriality by following the fortunes of a population of a very common species, the red-veined dropwing, which occupied our garden pond. During the course of the summer we caught and marked 407 males. By doing frequent roll-calls on the pond we chalked up over 8000 resightings of these recognisable individuals. Females lived in the bush away from the pond, only coming to it to mate and lay eggs, whereas males lived on or close to the pond throughout their adult life, roosting at night in nearby rank grass and taking up a position on the pond daily, usually coming on-site from about 09h00 to 17h00. The competition for territories was fierce as newcomers arrived daily and jostled for a place on the pond. Once secured, most males managed to retain a territory for at least 20 days, fewer for 30 days, and only a handful for 40 days or more, by which time these elderly survivors were ragged-winged from wear and tear.
Dragonfly diversity is highest in the warmer, wetter subtropical parts of South Africa and the coastal plain of KwaZulu-Natal is especially rich in species. The rivers and seasonal pans and streams of the Kruger National Park support about 92 species. These species occur widely across Africa. To find the species unique to the country you must go to the grassland and fynbos biomes where diversity is much lower but endemism is high.
Next time you encounter a dragonfly, spend a little time closely observing it. I’m sure you’ll be richly rewarded by what you see, and perhaps even join the fan club.
What are Odonata?
The order Odonata, which is what dragonflies are called technically, comprises two suborders: ‘true’ dragonflies and damselflies. The latter (far left) are distinguished by their more slender build, simpler wing design and their widely spaced eyes. Across the world the ratio of the two is about 60:40 and this is the case in South Africa, too. Because of the ambiguity arising from the use of the word ‘dragonfly’, as a group dragonflies and damselflies are often collectively referred to as odonata rather than dragonflies.