|Libellula is a genus of dragonflies,
commonly called Skimmers, in the family Libellulidae, distributed throughout
the temperate zone of the Northern Hemisphere. Most species are found in
the United States, where they are the best-known large dragonflies, often
seen flying over freshwater ponds in summer. Many have showy wing patterns.
The taxa Ladona (Corporals) and Plathemis (Whitetails) have been considered
as synonyms of Libellula, subgenera, or separate genera by different authorities.
Recent phylogenetic analysis has supported their status as either subgenera
or full genera. The genus contain 25 species.
Libellula pulchella (Drury, 1770),
the Twelve-spotted Skimmer, is a common North American skimmer dragonfly,
found in southern Canada and in all 48 of the contiguous U.S. states.
It is a large species, at length
48 - 53 mm, hindwing length 42 - 46 mm. Each wing has three brown spots.
In adult males, additional white spots form between the brown ones and
at the bases of the hindwings, and thus its name comes from; it is sometimes
called the Ten-spot Skimmer for the number of these white spots. The abdomen
of the male is white-blue or grey and has a powder-like appearance. The
thorax is brown with two stripes on each side, which are grey above and
yellow below. As it ages, the stripes on the thorax of the male become
The female is similar to the male
in appearance but has a brown abdomen and thorax, with continuous yellow
stripes along each side. Both the male and female also have white spots
between the darker spots on the wings, which develop with age. The eyes
of both sexes are red-brown. The juvenile is similar in appearance to the
The flight season of the twelve-spotted
skimmer, when the adults are active, varies throughout its range. Activity
usually occurs between late March and November, but is most common between
June and October. It is a highly territorial species, and the male defends
its territory from other dragonfly species, as well as its own. Conflicts
are usually won by the individual with the greatest flight agility, and
the winner gains a better territory or succeeds in retaining its original
territory. Disputes are usually between males over areas which are frequently
visited by females.
Libellula pulchella is common across
the United States, southern Canada and northern Mexico. Throughout this
range it is absent from certain areas in the far south and south-western
United States. There are not known to be any specific conservation measures
currently in place for this species, and it is not yet to be classified
by the IUCN.