Symphyla
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Scutigerellidae |
Symphylans, also known as garden centipedes or glasshouse symphylans, are soil-dwelling arthropods of the class Symphyla in the subphylum Myriapoda. Symphylans resemble centipedes, but are smaller and translucent. They can move rapidly through the pores between soil particles, and are typically found from the surface down to a depth of about 50 cm. They consume decaying vegetation, but can do considerable harm in an agricultural setting by consuming seeds, roots, and root hairs in cultivated soil.
Juveniles have six pairs of legs, but, over a lifetime of several years, add an additional pair at each molt so that the adult instar has twelve pairs of legs. Lacking eyes, their long antennae serve as sense organs. They have several features linking them to early insects, such as a labium (fused second maxillae), an identical number of head segments and certain features of their legs.[1]
About 160 species are known worldwide.[1]
The body is divided into a head and segmented trunk. The head has long, segmented antennae, a postantennal organ, three pairs of mouth-parts: mandibles, the long first maxillae, and the second pair of maxillae which are fused to form the lower lip or labium of the mouth. The trunk consists of 15-24 segments protected by overlapping dorsal plates, 12 (10) segments are leg bearing, the first segment is large and usually provided with a pair of legs, the last segment is slender lacks legs and possesses a pair of cerci and sensory structures (trichobothria or sensory calicles) distally on the abdomen. Immature individuals have six pairs of legs on hatching. The sexes are separate.
Symphyla are small, cryptic myriapods without pigment or eyes. The body is soft and from 2-10 millimetres long, with two body regions, a head and segmented trunk. The head has long, segmented antennae, a postantennal organ and three pairs of mouth-parts; mandibles, long first maxillae and second pair of maxillae fused to form the lower lip or labium of the mouth. The trunk consists of 15-24 segments protected by overlapping dorsal plates, segments 12 (10) are leg bearing, the first segment is large and usually provided with a pair of legs, the last segments are slender lacking legs, and possessing a pair of cerci and sensory structures (trichobothria or sensory calicles) distally on the abdomen. Immature individuals have six pairs of legs on hatching. The sexes are separate.
Symphyla are rapid runners. They are primarily herbivores and detritus feeders living deep in the soil, under stones, in decaying wood, and in other moist places where they feed on the root hairs and rootlets and can sometimes cause crop failure. The garden centipede, Scutigerella immaculata can be a serious pest of vegetable crops and tree seedlings and occurs in greenhouses as well as agricultural situations. A species of Hanseniella has been recorded as a pest of sugar cane and pineapples in Queensland (Boyle 1981; Murray & Smith 1983). A few species are found up trees (Adis & Scheller 1984; Clark & Greenslade 1996) and in caves (Eberhard & Spate 1995; Eberhard et al. 1991). A species of Symphylella has been shown to be predominately predacious (Walter et al. 1989) and some species are saprophagous. Worldwide, there are some 200 described species.
Seven genera and subgenera and 27 species are currently named in the Australian fauna with two species Symphylella A (WA), and Symphylella B (Qld) distinguished but not named (Scheller 1961). Tillyard (1930) illustrated a species as an undescribed Scolopendrella from Australia that Tiegs (1939) considers is probably referable to the “common” species Hanseniella agilis.
Only one species, Scutigerella immaculata Newport, is introduced. Apart from this, all species and one subgenus, Millotellina (Diplomillotellina), are endemic to Australia. The total Australian fauna is likely to comprise at least 150 species.
[edit] References
- Adis, J. & Scheller, U. (1984). On the natural history and ecology of Hanseniella arborea (Myriapoda, Symphyla, Scutigerellidae), a migrating symphylan from an Amazonian black-water inundation forest. Pedobiologia 27: 35-41
- Boyle, H. (1981). Symphyla control in young plant cane. Cane Growers' Quart. Bull. 44: 115-116
- Clark, S. & Greenslade, P. (1996). Review of Tasmanian Hanseniella Bagnall (Symphyla: Scutigerellidae). Invertebr. Taxon. 10: 189-212
- Eberhard, S.M. & Spate, A (1995). Cave Invertebrate Survey; toward an atlas of NSW Cave Fauna. A report prepared under NSW Heritage Assistance Program NEP 94 765.
- Eberhard, S.M., Richardson, A.M.M. & Swain, R. (1991). The invertebrate cave fauna of Tasmania. Unpublished Report. Zoology Department, University of Tasmnania.
- Edwards, C.A. (1990). Symphyla. pp. 891-910 in Dindal, D. (ed.) Soil Biology Guide. New York : Wiley
- Murray, D.A.H. &Smith, D. (1983). Effect of Symphyla, Hanseniella sp., on establishment of pineappes in south-east Queensland. Qld. J. Agric. Sci. 40: 121-123
- Scheller, U. (1961). A review of the Australian Symphyla (Myriapoda). Aust. J. Zool. 9: 140-171
- Scheller, U. (1982). Symphyla. pp. 688-689 in Parker, S.P. (ed.) Synopsis and Classification of Living Organisms. New York : McGraw-Hill Book Co. Vol. 2
- Tillyard, R.J. (1930). The evolution of the class Insecta. Pap. R. Soc. Tas. 1930: 1-89
- Walter, D.E., Moore, J.C. & Loring, S. (1989). Symphylella sp. (Symphyla: Scolopendrellidae predators of arthropods and nematodes in grassland soils. Pedobiologia 33: 113-116
