''Sminthurus viridis'' is a member of the

Collembola 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 ...

, the

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 ...

s, an order in the subphylum

Hexapoda The subphylum Hexapoda (from Greek for 'six legs') comprises most species of arthropods and includes the insects as well as three much smaller groups of wingless arthropods: Collembola, Protura, and Diplura (all of these were once considered ins ...

. The species is known by common names such as clover springtail,Department of Agriculture, Fisheries and Forestry (Queensland) The Department of Agriculture and Fisheries is a department of the Queensland Government which aims to maximise the economic potential for Queensland's primary industries on a sustainable basis through strategic industrial development. The secti ...

flea Flea, the common name for the order Siphonaptera, includes 2,500 species of small flightless insects that live as external parasites of mammals and birds. Fleas live by ingesting the blood of their hosts. Adult fleas grow to about long, a ...

Eurasia Eurasia (, ) is the largest continental area on Earth, comprising all of Europe and Asia. Primarily in the Northern and Eastern Hemispheres, it spans from the British Isles and the Iberian Peninsula in the west to the Japanese archipelago ...

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Description

Sminthuridae

As Collembola go, it is a fairly large species, commonly up to about 3 mm in length. The species has a well-developed

furcula The (Latin for "little fork") or wishbone is a forked bone found in most birds and some species of non-avian dinosaurs, and is formed by the fusion of the two pink clavicles. In birds, its primary function is in the strengthening of the thoracic ...

and it leaps actively if alarmed.Roberts, John & Umina, Paul. Lucerne Flea. AG0415. June, 2008 Centre for Environmental Stress and Adaptation Research (CESAR), University of Melbourne. Department of Environment, Land, Water and Planning (DELWP), Victoria, Australia The mouthparts of ''S. viridis'' are

mandibulate Mandibulata, termed "mandibulates", is a clade of arthropods that comprises the extant subphyla Myriapoda (millipedes and others), Crustacea and Hexapoda (insects and others). Mandibulata is currently believed to be the sister group of the clade ...

, meaning that they have biting mouthparts, though only the tips of the mandibles project out of the mouth folds.

Biology

The mature female lays variable batches of eggs, usually in damp soil or litter. Oviposition is slow; she takes a few minutes to lay each egg. The eggs are very difficult to find in the field because they are covered by sticky excreta containing soil that the female had swallowed. The eggs are spherical, pale yellow, and only about a 1/4 mm in diameter. Their resistance to both drought and cold has enabled the species to survive introduction from cool, moist conditions of Northern Europe, to Australasia and Southern Africa. In conditions of drought, they simply enter a state of aestivation in the form of

diapause In animal dormancy, diapause is the delay in development in response to regular and recurring periods of adverse environmental conditions.Tauber, M.J., Tauber, C.A., Masaki, S. (1986) ''Seasonal Adaptations of Insects''. Oxford University Press I ...

in which embryonic development is delayed. The delay lasts till a period of soaking rain sets in or until irrigation begins. During a period of active breeding when plenty of moisture exists, the hatching period is variable; under favourable conditions, most eggs hatch in about 2 weeks, but some take 3 weeks or more, while eggs that have aestivated hatch at various intervals over period around a week to a month or more after wet conditions return. When rain is delayed in spring, a bank of partly developed eggs in the soil may accumulate, leading to something of an explosion of emergence after good rain. Their lifecycles vary with climatic conditions and also with gender; males and female develop according to different schedules. Males are somewhat smaller than females and they undergo ecdysis only four times, after which they are ready for reproductive activity. They produce

spermatophore A spermatophore or sperm ampulla is a capsule or mass containing spermatozoa created by males of various animal species, especially salamanders and arthropods, and transferred in entirety to the female's ovipore during reproduction. Spermatophores ...

s mounted on fine stems well above the substrate surface. A female that encounters such a spermatophore might take it up into her cloaca or simply eat it if she is not receptive. Rival males might each other's spermatophores or even their own after they have failed to attract any female and are no longer viable. The female sheds her skin nine times, but achieves sexual maturity in the sixth

instar An instar (, from the Latin '' īnstar'', "form", "likeness") is a developmental stage of arthropods, such as insects, between each moult (''ecdysis''), until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or ...

, that is, after the fifth ecdysis. The earlier instars last for only a matter of days, but the sexually functional instars for a fortnight or so. The fully mature female might live for two months or more. Generations in the field overlap, but roughly four to eight generations a year might occur, depending on the region and conditions.

Pest status

''S. viridis'' often swarms in large numbers on living plants, especially Fabaceae. It commonly occurs on lucerne (an alternative name for alfalfa, hence the first part of the common name). It feeds mainly on the surface cells of leaves, and when it occurs in especially high densities, it causes enough damage to be regarded as an agricultural pest. In this respect, it is unusual among Collembola, because very few members of the suborder do significant harm and some actually are mildly beneficial, either as predators or in recycling detritus. The biological control of ''S. viridis'' is fairly complex and reasonably effective where it is adequate, because no one agent accounts for the entire control. For instance, fungal infections have been documented as killing the springtails, though they are not seen as major control agents.Keller, Siegfried; Steenberg, Tove / Neozygites sminthuri sp. nov. (Zygomycetes, Entomophthorales), a pathogen of the springtail Sminthurus viridis L. (Collembola, Sminthuridae) Sydowia, Vol. 49, No. 1, 1997, p. 22-24.

References

{{Authority control Collembola Animals described in 1758 Arthropods of Europe Taxa named by Carl Linnaeus