''Folsomia candida'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

springtail Springtails (Collembola) form the largest of the three lineages of modern hexapods that are no longer considered insects (the other two are the Protura and Diplura). Although the three orders are sometimes grouped together in a class called Ento ...

in the family

Isotomidae Isotomidae is a family of elongate-bodied springtails in the order Entomobryomorpha. Genera These 109 genera belong to the family Isotomidae: * '' Aackia'' Yosii, 1966 * '' Acanthomurus'' Womersley, 1934 * '' Aggressopygus'' Potapov & Babenko, ...

. It is found in soil in many locations around the world, having been spread inadvertently by humans. It reproduces by

parthenogenesis Parthenogenesis (; from the Greek grc, παρθένος, translit=parthénos, lit=virgin, label=none + grc, γένεσις, translit=génesis, lit=creation, label=none) is a natural form of asexual reproduction in which growth and developmen ...

and has been used as a model organism in research.

Description

''Folsomia candida'' has an unpigmented, slender body up to in length. The head bears a pair of four-segmented antennae and a pair of post-antennal organs but no eyespots. The dorsal part of the first thoracic segment is reduced and the posterior three abdominal segments are fused. The ventral side of the fourth abdominal segment bears a furca, used in jumping, and it is the number of

bristles A bristle is a stiff hair or feather (natural or artificial), either on an animal, such as a pig, a plant, or on a tool such as a brush or broom. Synthetic types Synthetic materials such as nylon are also used to make bristles in items such as br ...

on this organ that distinguishes this species from others in the genus.

Distribution and habitat

This springtail has been called a "tramp" species as it has spread around the world in soil and in plant pots and its original distribution is unclear. It occurs in mines and caves, and in soils with a high organic content, on farms, in leaf litter in forests and on stream verges.

Ecology

Populations consist only of females, which reproduce by

. The globular white eggs take about one week to hatch at and three weeks to reach maturity, having moulted five times. Development takes longer at lower temperatures. Adults continue to moult, doing so about 45 times during their lives, including shedding the lining of the midgut. They may live for 110 to 240 days, depending on the temperature, and each may lay about a thousand eggs. The diet consists mainly of the hyphae of fungi including grazing on root mycorrhizae. Invertebrates living among the soil particles in underground habitats often experience raised levels of

carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is trans ...

, which tends to increase with depth. Researchers have found that the surface-dwelling springtail ''

Allacma fusca ''Allacma fusca'' is a species of springtail. This species is endemic to western areas of Continental Europe and the British Isles, where it lives in the surface layers of the soil in moist habitats such as among leaf litter. Description ''All ...

'' can tolerate a 10% level of carbon dioxide for a few hours while in contrast, ''Folsomia candida'', which lives deeper in the soil, can survive under the same conditions for more than six weeks. It is unclear whether springtails in soil are on balance beneficial to crops or disadvantageous. In the case of ''Folsomia candida'', beneficial actions include feeding on plant-pathogenic nematodes and mites.

Use in research

''Folsomia candida'' is easily kept in the laboratory where it can be maintained on granulated

baker's yeast Baker's yeast is the common name for the strains of yeast commonly used in baking bread and other bakery products, serving as a leavening agent which causes the bread to rise (expand and become lighter and softer) by converting the fermentabl ...

. Researchers have developed strains bred from single individuals. It has been used for over forty years to test the effects, on non-target soil invertebrates, of pesticides and soil

pollutant A pollutant or novel entity is a substance or energy introduced into the environment that has undesired effects, or adversely affects the usefulness of a resource. These can be both naturally forming (i.e. minerals or extracted compounds like o ...

s. It has also been used as a model organism to investigate many different characteristics including cold tolerance, carbon dioxide tolerance and the effects of its grazing activities on soil fungi and mycorrhizae growing on roots. It has been used to study the processes involved in the decomposition of leaf litter, circadian rhythms,

circaseptan A circaseptan rhythm is a cycle consisting of approximately 7 days in which many biological processes of life, such as cellular immune system activity, resolve. See also *Circadian rhythm *Chronobiology Chronobiology is a field of biology th ...

(weekly) rhythms, the palatability and nutritious value of different plant residues and species of fungi, the effects on ageing of different environmental conditions, population dynamics and behaviour. Strains have been kept growing in cultures for upwards of five years, and excess individuals can be used as invertebrate food for other organisms kept in the laboratory.

References

{{Taxonbar, from=Q10497530 Collembola Animals described in 1902