Wandering Glider
Pantala flavescens
Summary 3
Pantala flavescens, the globe skimmer, globe wanderer or wandering glider, is a wide-ranging dragonfly of the family Libellulidae. This species and Pantala hymenaea, the "spot-winged glider", are the only members of the genus Pantala from the subfamily Pantalinae. It was first described by Fabricius in 1798. It is considered to be the most widespread dragonfly on the planet with good population on every continent except Antarctica although rare in
Characteristics 4
The dragonfly is up to 4.5 cm long, reaching wingspans between 7.2 cm and 8.4 cm. The front side of the head is yellowish to reddish. The thorax is usually yellow to golden coloured with a dark and hairy line. There were also specimens with a brown or olive thorax. The abdomen has a similar colour as the thorax.
The wings are clear and very broad at the base. There, too, there are some specimens with olive, brown and yellow wings. On Easter Island there are wandering gliders with black wings.
The pterostigma turns yellowish. The transparent wings may turn a yellowish shade towards the tip. The chestnut-red eyes take up most of the head, as is usual in the large dragonflies (Anisoptera). The above colours explain the many scientific descriptions of this species under different names.
Females show some differences compared with males. The general rule is, the males have reddish yellow abdomen marked with black whereas the females lack the reddish wash in abdomen. The males have golden yellow patch on base of hindwings and narrow apical brown spot at the hind border of wings. The females lack apical brown patches in wings.
In mainland males, the length of the femur, the longest leg section, varies; they also have longer front and shorter hindwings than the females. The island representatives, however, have the front and hindwings longer than the female, and the femur is the same for both sexes. There are other differences between mainland and island specimens, particularly in terms of colouring. Island representatives are generally darker.
The larva is between 24 and 26 mm long. It is light green with light, brown speckles. The round eyes are sideways on the bottom of the head, the abdomen and the tail blunt.
The paired side plates on the eleventh segment of the abdomen, the so-called paraproct, is smooth when seen from the side. The unpaired dorsal plate of the eleventh segment, called the epiproct, is roughly the same length as or longer than the paraproct. This distinguishes them from larvae of the genus Tramea, where the epiproct is shorter than the paraproct. Furthermore, the mouth parts (palpus) have 12–14 bristles and thus fewer than P. hymenaea which has 15–18 bristles.
Pantala flavescens may be confused with the P. hymenaea, the "spot-winged glider", but this has a striking brown basal fleck in the hindwing and is generally slightly darker in colour. It might be taken for a member of the genus Tramea but these usually have a distinctive stripe on their hindwings.
Common name 4
The English common names "wandering glider" and "globe skimmer" refer to its migratory behaviour. The German name Wanderlibelle means "migrant dragonfly". In Hong Kong, its name translates as "typhoon dragonfly" as it arrives with or shortly before the seasonal rain. The Japanese name is usubaki-tombo (ウスバキトンボ) which is translated as "yellow dragonfly with delicate wings". Similarly, the South Korean name is '된장잠자리'(translated as "doenjang dragonfly") because its colour is similar to doenjang, the Korean bean paste.
Distribution and flight 4
The globe skimmer, as its name suggests, has a very wide distribution area, between about the 40th parallels of latitude or within the 20 °C isotherm (areas of the world where the annual mean temperature is above 20 degrees Celsius), and up to about the 50th parallel north in North America. In Europe there are only occasional sightings of the species, with credible evidence to date mainly from the Aegean Sea and the adjacent mainland. Globe skimmer records from England or France are doubtful and may arise from co-importation with shipments of bananas. An explanation for the scarcity in Europe of this otherwise common species is the barrier effect of the Sahara which generates unfavourable winds, such as the Sirocco, whose dryness makes dragonfly passage almost impossible.
Their arrival in the subtropics and tropics coincides with the Intertropical Convergence Zone. More evidence of their preference for moist winds is that the dragonfly migrates to Southeast India's Tamil Nadu only after the second monsoon, which brings the rain to that region. In the rest of India, however, it arrives with the first rain-making monsoon. Observations and stable isotope evidence suggests that they migrate from India or beyond to Africa across the Arabian Sea.
It is the highest-flying dragonfly, recorded at 6,200 m in the Himalayas. It was also first dragonfly species that settled on Bikini Atoll after the nuclear tests there. Furthermore, it is the only Odonata on Easter Island. These individuals seem to be a small gene pool, derived from the continental populations, which is slowly creating a new type by genetic drift. In colder areas like South Australia and Southern Canada, the species cannot overwinter and must therefore be replaced by new migrants each year.
According to recent research carried out by biologists at Rutgers University-Newark this species of dragonfly is the world's longest known distance insect traveller. Genetic evidence taken from dragonflies across the globe suggests that these small size insects are travelling vast distances to mate and are thus creating a worldwide gene pool. Another study concluded that Pantala flavescens is a near global panmictic population.
Flight behaviour 4
They are very conspicuous dragonflies; seen in swarms over paddy fields, playgrounds or open areas. They fly tirelessly with typical wandering flight for hours without making any perch. Their flight speed is up to 5 m/s. Especially in the autumn, the wandering glider flies in large swarms, using thermals to advantage. One report even speaks of a "cloud" covering 34 km2. They prefer moist winds. In normal flight, island populations keep to 2.5 meters above the ground and stop flying in thermal updraughts. The continental populations fly at altitudes of three to four meters, and do not stop flying even in bad weather. Those on Easter Island have adapted away from their migratory habits because to fly out to the open sea would usually mean certain death.
When landing, it seeks a vertical attitude. Like all large dragonflies, the wings are held out from the body at rest.
Sources and Credits
- (c) Ryosuke Kuwahara, some rights reserved (CC BY-NC), uploaded by Ryosuke Kuwahara
- (c) Ken-ichi Ueda, some rights reserved (CC BY), uploaded by Ken-ichi Ueda
- Adapted by Greenpigeonsnaturelk from a work by (c) Wikipedia, some rights reserved (CC BY-SA), https://en.wikipedia.org/wiki/Pantala_flavescens
- (c) Wikipedia, some rights reserved (CC BY-SA), https://en.wikipedia.org/wiki/Pantala_flavescens
More Info
iNat Map
| Taxonomy:family | Libellulidae |
|---|---|
| Taxonomy:suborder | Anisoptera |
| Taxonomy:species | Pantala flavescens |
