Collembola
Description
Members of the Collembola Family are relatively small, typically less than 6 millimeters in length, with as many as six abdominal segments [1]. They have a tubular appendage called a collophore, which protrudes from the first abdominal segment. The collophore used to be thought to be a stabilizing mechanism for the collembola when it jumped by sticking to the surface on which it landed. More recent research has concluded that the collophore is used in osmoregulation, water intake, and excretion [2].
Collembola that live in the upper soil layers are often referred to as Springtails because of a tail-like appendage found among most species, called the furcula. It is a forked appendage attached to the fourth segment by a structure called the retinaculum and is used for jumping when the animal is threatened; it is not used for normal locomotion [3]. In as little as 18 milliseconds the furcula can be released from the retinaculum, snapping against the substrate and flinging the springtail into the air[4]. A reason that this mechanism is not used in typical locomotion is that it’s direction is very unpredictable. When the furcula is released, the springtail is sent tumbling through the air on an arbitrary trajectory, landing randomly [3].
Springtails are able to reduce their body size by up to 30% through genetically controlled molting if temperatures are high enough. Warmer conditions increase energy needs, as well as metabolic rates; a smaller body size comes with many advantages to the organism [5].
Habitat & Distribution
Evolution
Environmental Impacts
References
1. Davies, W. Maldwyn (1927). "On the tracheal system of Collembola, with special reference to that of Sminthurus viridis, Lubb" (PDF). Quarterly Journal of Microscopical Science. 71 (281): 15–30.
2. Eisenbeis, G., 1982. Physiological absorption of liquid water by Collembola: absorption by the ventral tube at different salinities. Journal of Insect Physiology 28:11–20.
3. Christian, E., 1978. The jump of the springtails. Naturwissenschaften 65:495-496.
4. Piper, Ross (2007). Extraordinary animals: an encyclopedia of curious and unusual animals. Santa Barbara, California: Greenwood Press.