Ischnura ramburii

Rambur's Forktail

Ischnura ramburii, Rambur's Forktail, Coenagrionidae

Family: Coenagrionidae

Length: 27-36 mm

 

Ischnura ramburii is a nonterritorial damsefly found at the edge of ponds. The life expectancy of a newly emerged damselfly in genus Ischnura is 4-10 days.

Favored food items of Ischnura ramburii include leafhoppers, flies, moths, and other damselflies (even other Ischnura ramburii). In turn, the Ischnura ramburii are preyed upon by birds, frogs, spiders, dragonflies, and damselflies. Fish are among the predators of larval damselflies including those of this species.

Rambur's Forktail is one of a number of damselflies that have two forms of female, one colored like the males and one colored differently. One theory is that the females that are colored like males may be relieved of the constant pressure by males to mate. Females may gain nothing by numerous additional matings after their first mating, and such matings can interfere with their feeding and predator avoidance.

Sirot and Brockman (2001) showed that the male-like females did not have an advantage over the differently colored females, based on such measures as number of eggs laid. They added, however, that their laboratory experiments might be misleading compared with behavior of the species in the field. For example, mating may be more dangerous in the wild, where females often fall into the water and are trapped on the water surface, where they are preyed upon by frogs or fishes.

Photo location for upper four photos: Sanderling, North Carolina. The photo above and the one immediately below show a male-like female, identifiable as female by the appendages.

Rambur's Forktail, dorsal view of male

Ischnura ramburii, orange form female

Above and below: Immature female adults sport this orange color pattern.

Ischnura ramburii, lateral view of throax

Locale of the photo below: Oranjestad, Aruba.

Ischnura ramburii, image from Aruba

Map, Ischnura ramburii (United States records)

Map, Ischnura ramburii, Mexico, Central America, and Caribbean

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