Family: Lestidae
Length: 50-62 mm
This species is the only spreadwing found in West Virginia (and indeed in the region) that is not a member of the genus Lestes. It is enormous, the largest damselfly in the state and region, reaching lengths of more than 60 mm. Like other spreadwings, it holds it wings out to the side, almost like a dragonfly, though not as widely spread.
Viewed from above, the thorax is brown and has a broad green stripe on each side. In older individuals this green stripe is dull or obscured by pruinesence. Viewed from the side, the lower part of the thorax has two broad yellow stripes (the lower one may seem incomplete).
The tip of the abdomen is whitish.
As in all male spreadwings, Great Spreadwing males have a very prominent clasper used to clasp the female in mating. Females are similar to the males but have a thicker abdomen, and of course females have an ovipositor instead of the claspers.
Male Great Spreadwings spend a lot of time hanging diagonally from waterside plants such as cattails, only occasionally flying out to feed or look for females. Females are seldom seen at the water until time to mate; prior to this they are seen feeding in the woods or woods margins.
Bick and Bick (1970) report that Archilestes grandis prefers to oviposit in Sycamore petioles. Other plants sometimes used for oviposition include various species of mint, sorrel, and verbena. One unsual trait of ovipositing Great Spreadwings is that they lay their eggs high in trees, in some cases even 10-13 meters up. The tandem pair chooses locations where they can see water below, since the hatchlings (prolarvae) will need to drop down into the water to begin their nymphal development period. Bick and Bick twice observed the hatching of Archilestes grandis eggs. On one occasion, observing in a stereomicroscrope, they saw the prolarva emerge from the egg and seem to jump; about a minute later they located the creature in a petri dish of water below the microscope setup, already having molted to the next stage. They noted, "The prolarval stage could hardly have lasted more than one minute."
Once considered a species of the southwestern U.S., the Great Spreadwing has moved into the East and then the Northeast, and is fully established as a West Virginia resident. Look for Great Spreadwings at ponds, temporary ponds, and slow-moving streams. They are seen most often in West Virginia in August and September.
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| The two broad yellow stripes are key characteristics for this species, as is the large size (for a damselfly) which is sure to get your attention. |
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| Note the blue eyes and face. On this specimen the green dorsal stripes are starting to be obscured by pruinosity. |
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| Another female is pictured above, this time in profile. Note the thicker abdomen, also the ovipositor (the appendage at the tip of the abdomen, below the main part of the abdomen). At lower right are exuviae, cast off by the aquatic larvae when they left the water for the last time. |
