malaeng poh (แมลงปอ)
Thai.
Generic name for ‘dragonfly’, as well as ‘damselfly’,
though the latter is officially known as
malaeng poh khem (แมลงปอเข็ม), literally
‘needle dragonfly’. These two types
of insects have elongated bodies, two pairs of strong, usually
transparent wings, and large multifaceted eyes, and both belong
to the order Odonata. Dragonflies are similar to damselflies, but in
resting adults the wings of the latter are held along and parallel
to the abdomen (fig.), whereas those of dragonflies are held away from and
perpendicular to the body (fig.).
Dragonflies have a life span of more than a year and up to several
years, but very little of that life is actually as an adult
dragonfly. Most of their life cycle is lived out in the nymph stage,
underwater, in still and calm waters. At the end of the nymph stage,
it will crawl out of the water to complete its metamorphosis into a
dragonfly. It does so by shedding its skin, which is left behind as
an empty shell, known as the exuvia (fig.).
These empty shells can often be found sticking on the spot where the
dragonfly emerged, even long after the actual event. Dragonflies are
among the greatest flyers in nature: they can hover, fly backwards,
and even upside-down, as it is able to move all four wings in
different directions at the same time. When patrolling their
territory, they fly with speeds of more than 50 kilometers an hour
and are able to dart off at top speed from a standing start, yet
when traveling long-distance they can reach speeds of up to 130
kilometers per hour. With only about 30 flaps per second, they beat
their wings so slowly that they don't produce a humming or buzzing
sound but a sizzle.
There are more than 5,000 species
worldwide, of which 295 are found in Thailand and with over 190
species, Chiang Mai is reported to have more dragonflies and
damselflies than any other province in the country. Both dragonflies and damselflies have a unique mating process in which the male grips the female behind its head with pincers at the end of its abdomen while the female bends her lower body forward to unite with the male
genitalia on the frontal underside of its abdomen. This unusual position is known as a
mating wheel. The male's grip can last for anything between a few seconds to an hour, while many damselflies usually stay connected while the female lays her eggs, usually on water, though some species hide them in moss cushions or in between stones, where rain shower will eventually flush tier eggs into the water. The damselfly couple will fly in tandem to a location on the water, where the female will either poke her abdomen under the surface to deposit her eggs on the underside of an aquatic plant or leaf, all the time with the male still attached on the back of her head, or she will dive underneath the surface to attach her eggs to a plant underwater, being able to stay down up to 90 minutes. While in some species of dragonfly, the female lays her eggs alone, other species of dragonfly also fly united in tandem while the female individually taps her eggs onto water plants with out ever landing. Commonly found
species in Thailand include the
Crimson Marsh
Glider
(Trithemis aurora -
fig.),
the
Indigo
Dropwing
(Trithemis festiva -
fig.), the
Scarlet
Skimmer or Crimson Darter (Crocothemis servilia servilia),
etc. In Japan dragonflies
symbolize martial success, due to the similarity of sound in the
Japanese words for dragonfly and victory.
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