14 Ocak 2013 Pazartesi

Alaska State Insect

Alaska State Insect

Four-spot skimmer dragonfly (common name)
Libellula quadrimaculatas 
(scientific name)


The four-spot skimmer species is about 300 million year old. Skimmers are large insects (almost two inches, or 4.2 cm, long) and have wingspans longer than their bodies. The bodies are comprised of a head with very large eyes, a stout furry thorax, and a vivid orange abdomen with a yellow line along each side. The base of the hind wings is rounded, and there are two dark– brown spots at the leading edge of each set of wings, making the insect’s appearance quite distinctive.


Wingspan: 2 3/4–3 1/8 in (6–8 cm)
 Odontate larvae are called nymphs or naiads. They feature short abdomens covered with spines and knobs, small eyes, long antennae, short legs, and a double-hinged jaw that juts out to capture prey with hooked teeth.
Adult: Three months
 The larval stage comprises the majority of the insects’ lifespan. The larva goes through a dozen molts over a period of typically two years before its metamorphosis into a flying insect.
Ponds, vernal pools, and slow-moving rivers.
Range: Labrador to New Jersey in the east; Alaska to Arizona in the west. The four-spot has a circumpolar range around the northern hemisphere from Europe to Japan as well as across the United States and Canada.
Flight period: Early April to mid-August. They are most active in June and July.
Conservation status: Secure globally, but now rare in parts of its traditional range.
Males often perch around the margins of pools and ponds with good visibility and will often return to these same perches. The male is highly aggressive and will patrol its territory and defend it from incursions by other dragonfly males. Both sexes are in almost constant motion, and mating even takes place in the air. Females lay their eggs on floating vegetation in April through October, and the eggs hatch shortly afterwards. Larvae overwinter before hatching in the spring. The four-spot is an aggressive hunter of other insects, including smaller dragonflies. They do not bite or sting, but rather bite their prey.
Adults: Small, flying insects primarily mosquitoes, gnats, and midges.
Larvae: Aquatic insect larvae, tadpoles, and even minnows.
  • In 1995 votes were tallied from every Alaskan elementary school in the state, and the children nominated the four-spotted skimmer as the state insect. The dragonfly narrowly defeated the mosquito by a vote of 3,914 to 3,035. The state legislature subsequently declared the skimmer the state insect. In a sponsor statement for the bill State Rep. Irene Nicholia said, "The dragonfly’s ability to hover and fly forward and backward reminds us of the skillful maneuvering of the bush pilots in Alaska."
  • A variant form more common in Europe, praenubila Newman, has larger wing spots, possibly due to higher water temperatures during larval development.

Click to enlarge an image
State Insect
Four-spot Skimmer Dragonfly
State Insect
Close-up of Four-spot Skimmer Dragonfly
State Insect
Four-spot Skimmer Dragonfly Emerging from Larva
State Insect
Blue Flower Reflected in Four-spot Skimmer Dragonfly Eye

Species:L quadrimaculatas
Author: World Trade Press

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