slender springtail

Entomobrya clitellaria is a native, small, slender springtail. It occurs in the United States and southern Canada east of the Great Plains and on the West Coast.

Adults are small, up to 1⁄32″ to 1⁄16″ (1 to 2 mm) in length. The body is elongate and almost cylinder-shaped. It is not covered with scales. The color is highly variable. Four color forms have been described, all of which have also been considered separate species. The ground color is pale brownish yellow (pale), and there are some dark brown or dark blue to almost black (dark) areas and markings. The head, thorax, abdomen, and legs are covered with short, fine hairs. The thorax also has long, erect, clubbed hairs, and toward the end of the abdomen there are long, erect, sharply bent hairs.

The head is about as long as it is wide. On each side of the head there is a “composed eye”, which is a cluster of 8 simple eyes (ocelli) and no compound eyes. The front two ocelli on each side are large, at least twice as large as the others. The eye patches are dark. The antennae are shorter than the body and they have 4 segments. They are pale with a variable amount of dark pigmentation at the ends of segments 3 and 4 and at the base of segment 3. Segment 2 is shorter than segment 4, and segment 4 is slightly thicker than segment 3. There is no postantennal organ.

The thorax has 3 segments, and each segment bears a pair of legs. Segment 3 is dark.

The abdomen has 6 segments. Segment 4 is at least four times as long as segment 3, and at least as long as segments 1 through 3 taken together. The fourth segment has a spring-loaded, forked, tail-like appendage (furca) used for jumping. The furca is long, slender, and curved. It is held folded under the abdomen, locked in place by a clasp-like structure (retinaculum) on the third abdominal segment. When it is released, it launches the springtail into the air. The color of the abdomen is highly variable. Segments 1 and 2 are dark, and the upper (dorsal) side of segment 3 is dark. The presence and amount of dark pigmentation on abdominal segments 4 through 6 and on thoracic segments 1 and 2 are what define the 4 color forms of this species.

The legs are mostly pale with a variable amount of dark pigmentation.

Total length: 1⁄32″ to 1⁄16″ (1 to 2 mm)

Sources

29, 30, 82, 83.

Guthrie, Joseph E. & Geological and Natural History Survey of Minnesota. (1903). The collembola of Minnesota.

According to Guthrie, this species “was taken in the pine woods in the northern part of the state,” and was “fairly abundant” on the bark of red pine (Pinus resinosa). However, no specific location information was given.

Locally common to abundant

This species has no common name. The common name for the Family Entomobryidae is slender springtails, and it is applied here for convenience.

Alfredo Colon
6/11/2024

Location: Albany, NY