Collembola

Common names: springtails, collembolans, lucerne flea

Probability of encounter: high

Quarantine importance: some species are pests of plants.

Similarity to mites: small size and ubiquity.  Members of the Symphypleona and Neelipleona have indistinct segmentation and are most likely to be confused with mites, but all have antennae and a collophore.

Normal adult length: <3 mm (0.5 - 10 mm)

Body tagmata: head, thorax, abdomen (6-segmented, with ventral tube on S1 and furcula on S4, cerci absent)

Eyes: 8 + 8 ocelli maximum

Antennae: 4 segmented (sometimes subdivided)

Mouthparts: entognathous, mandibles usually with molar area; short buccal cone in some taxa; labial & maxillary palps usually vestigial

Legs: 3 thoracic pairs (subcoxae + 4 segments: coxa, trochanter, femur, tibiotarsus); single claw (unguis) + empodial appendage (unguiculus)

Distinguishing features: trichobothria, postantennal organ (olfactory), pseudocelli (head and body of Onychiuridae), distal furcula (furca), genital opening on S5.

Comments: Springtails have two basic body forms - elongate and rounded.  The elongate species usually have clearly defined abdominal segmentation, but those with rounded bodies lack clear segmentation. 

Springtails always have a distinct head with antennae and may or may not have simple eyes (ocelli).  The mouthparts are mandibulate, but withdrawn into the head and difficult to see.  Neanurine springtails have a short, cone-like beak and appear to be fluid feeders.  The thorax has three pairs of legs that end in distinctive claws, and the abdomen usually ends with a forked appendage - the furcula (or furca) - that is used to propel them through the air when threatened.

Springtails are very common and often abundant in any kind of soil, moist or rotting wood, and areas with mildew or other fungal growths, including low growing plants, the trunks of trees, and suspended soils.  Springtails were among the first terrestrial arthropods and most species feed on microbes, detritus, and minute invertebrates (e.g. nematodes).  Some are predators and a few species feed on plants and are important pests - e.g. the lucerne flea.  In life, most species are greyish to pale brown or colorless (white); however, some soil-dwellers are brightly colored (orange or boldly patterned in white and bluish grey).