Enchytraeid Species Research Articles

Effects of benomyl on reproduction and population structure of enchytraeid oligochaetes (Annelida)—Sublethal tests on agar and soil

1. 1. The toxicity of the fungicide benomyl to terrestrial enchytraeid species was tested under different conditions. 2. 2. Despite a relatively low acute response even to higher concentrations in agar media, sensitive effects were observed for cocoon production and hatching success at the recommended concentration for agricultural application (5.9 ppm in the test medium). 3. 3. These sublethal effects could be reconciled with population tests in larger quantities of soil: lower abundance was due to a very low number of juveniles in the benomyl-treated cultures.

Influence of Cognettia sphagnetorum (Oligochaeta: Enchytraeidae) on nitrogen mineralization in homogenized mor humus

The influence of the enchytraeid species Cognettia sphagnetorum on N mineralization in homogenized mor humus was examined in a laboratory study. The mor humus was incubated in containers (150 ml) for 8 months at various temperatures and with different moisture levels. Two series were used, one with C. sphagnetorum and one without. The presence of enchytraeids in the cultures increased the level of NH4+ and NO3- by about 18% compared with the cultures without enchytraeids. Almost 40% of this difference was explained by the decomposition of dead enchytraeids. Temperature and soil moisture were the most important factors controlling the mineralization rate. The optimum moisture for N mineralization was between pF 1.6 and 1.1.

Quantitative investigations of the food of two terrestrial enchytraeid species (Oligochaeta)

Quantitative investigations of the food of two terrestrial enchytraeid species (Oligochaeta)

Effect of human treading on enchytraeid fauna of hornbeam-oak forests in Hungary

The effect of human treading on the composition of the enchytraeid fauna was studied on hiking trails in hornbeam-oak forests in Hungary. Compaction of the soil due to continuous treading has an unfavourable influence on the enchytraeid fauna, with density and species richness decreasing significantly. However, an interesting result is that one species, Fridericia conculcata, prefers these heavily trodden areas.

Enchytraeid oligochaetes as marine pollution indicators

Fifteen species of enchytraeid oligochaetes have been collected from a pulp mill waste receiving area. Of these, one species Lumbricillus lineatus which is a known stressresistant intertidal form is predominant within 1.5 km of the mill outfall. Beyond that distance the species is replaced by a variable association of 14 other species from the genera Lumbricillus, Marionina and Enchytraeus. L. lineatus is common in Europe and eastern North America in upper intertidal drift habitats, but on the Pacific Coast is not indigenous. In British Columbia it has only been collected adjacent to three pulp mills, not at five other such mills, nor at ten undisturbed intertidal stations at each of which a diverse association of Enchytraeid species occurs. L. lineatus can serve as an index of the impact of pulp mill effluent at the site investigated. The most practical index is percentage of total adult enchytraeids represented by L. lineatus.

Distribution, Abundance and Life Cycles of Oligochaeta from the Marine Hygropsammal with Special Reference to the Phallodrilinae (Tubificidae)

AbstractTubificid and enchytraeid oligochaetes are common members of the interstitial fauna of sandy beaches. Their abundance dynamics, life cycles and distribution patterns were investigated at two beaches on the western Baltic Sea and at a North Sea beach (Isle of Sylt). Populations of 115,000 ind./m2 were found at protected Baltic beaches. Reproduction of the tubificids, Phallodrilus monospermathecus and Spiridion insigne takes place within a well defined breeding period once a year. The market horizontal and vertical distribution patterns of various tubificid and enchytraeid species are elucidated by preference reactions to several physiographic parameters, such as oxygen and water content of the sediment, and salinity.

Three new species of Enchytraeidae (Oligochaeta) from Ireland

Descriptions are given of three new species of enchytraeid, each of which is recorded from several localities in Ireland. The species are compared with other members of their genera and some details of their ecology are given. The paper includes a review of the genus Cernosvitoviella with a comparison of the nine European species.

Marine Oligochaeta from the Koster Area, West Coast of Sweden, with Descriptions of Two New Enchytraeid Species

A total of 28 species of marine Oligochaeta (belonging to the families Naididae, Tubificidae and Enchytraeidae) are reported from eulittoral and sublittoral sediment samples taken in the Koster area on the Swedish West Coast. Lumbricillus algensis sp.n. and Grania ovitheca sp.n. are described and their morphological and taxonomical relations to other enchytraeids are discussed. L. algensis is characterized mainly by its spermathecae, which project into segment VI, and by its very large penial bulbs. G. ovitheca possesses no dorsal setae, the ventral setae being present posterior to the clitellum only, and its spermathecae consist of a narrow duct and a large egg‐shaped to oval ampulla, filling most of the coelom of segment V. Four sublittoral species, Limnodriloides barnardi (Tubificidae), Lumbricillus semifuscus, Marionina sublitoralis and Grania roscoffensis (all Enchytraeidae) are reported as new to the Swedish fauna.

A description of five new species of Enchytraeidae (Oligochaeta) from Ireland

Descriptions are given of five new species of enchytraeid from Ireland. Cernosvitoviella sphaerotheca sp. nov. has a long spermathecal duct and cylindrical sperm funnel. Cernosvitoviella goodhui sp. nov. is closely related to C. aggtelekiensis. Cognettia hibernica sp. nov. is a small species resembling C. lapponica but the transition between oesophagus and intestine is abrupt, a character not previously observed in this genus. An emended diagnosis of the genus Cognettia is given. The distinguishing feature of Fridericia discifera sp. nov. is a very large spermathecal ampulla with two disc-shaped diverticula. Marionina minutissima sp. nov. has conspicuous cutaneous glands and lacks posterior dorsal setae. Cernosvitoviella sphaerotheca and Cognettia hibernica are common and widespread in Ireland. The taxonomic relationships of the species and other members of their genera are discussed.

Marionina charae, a new species of enchytraeid (Oligochaeta) from the Canadian arctic

Marionina charae n. sp. was collected from a stream flowing out of Char Lake, Comwallis Island, in the Northwest Territories of Canada. Thirteen species of Marionina have now been described from North America, and seven species of enchytraeid have been found in the North American arctic.

Aspects of the Distribution, Life History and Metabolism of the Enchytraied Worms Lumbricillus rivalis (Levinsen) and Enchytraeus coronatus (N & C) in a Percolating Filter

The principal function of percolating filters used in the treatment of sewage and organic wastes is to break down organic matter, oxidizing the organic carbon to carbon dioxide. Solids are generally made more readily settleable, ammonia is frequently oxidized to nitrate, and toxic metals such as zinc and copper are partially adsorbed by the attached microbial film. The role of invertebrates present in filters in maintaining the efficiency of such systems is a complex one. It has already been demonstrated from experimental studies (Williams & Taylor 1968) that both enchytraeids and psychodid flies can prevent the blocking of filter interstices by microorganisms and sewage solids, such blocking resulting in the development of anaerobic conditions and a declining efficiency of treatment. Further experiments have been conducted (Solbe, Ripley & Tomlinson, in preparation) which demonstrate the effect of temperature on their activity and metabolism. The present study was carried out on the filter described by Solbe, Williams & Roberts (1967). The rate at which the two most abundant enchytraeids Lumbricillus rivalis and Enchytraeus coronatus consumed organic matter has been calculated from estimates of their numbers and biomass in the filter, together with laboratory measurements of their rate of consumption of oxygen. The result has been compared with the total rate of dissipation of organic matter within the filter. In determining enchytraeid densities and size distributions for biomass estimates, information on the biology of the two enchytraeid species present, particularly their lifehistories and depth distributions, has also been collected and is presented here. In the past, most faunal studies of percolating filters have been limited to surface and subsurface sampling and consequently have not adequately taken into account vertical gradients in distribution, their influence on the interaction between species and their importance in studying species requirements and life-histories.

New Enchytraeidae (Oligochaeta) from the east coast of Vancouver Island

The following new species of littoral enchytraeid are described from the east coast of Vancouver Island, British Columbia—Enchytraeus cryptosetosus, Lumbricillus mirabilis, L. vancouverensis, L. georgiensis, L. qualicumensis, L. belli. These descriptions bring the number of North American Enchytraeus spp. to 6 and that of Lumbricillus spp. to 13. Existing evidence suggests that the enchytraeid fauna of the Pacific slope is quite distinct from that of the rest of North America and may have closer affinities with that of the northwest Pacific.

A new species of Lumbricillus, with a revised check-list of the British Enchytraeidae [Oligochaeta

A new species of enchytraeid worm, Lumbricillus christenseni, is described and compared with some closely related members of the genus Lumbricillus.Twelve other species of enchytraeid, recorded in the British Isles for the first time, are listed.The habitats and localities in which these new records have been found in North Wales and Europe are also listed.A revised check-list of the British Enchytraeidae is given.Following the publication (Nielsen & Christensen, 1959) of a critical revision of the taxonomy of European enchytraeids, which resolved much of the confusion in the existing literature, the task of identifying the members of this family has been made much easier. Between 1961 and 1964, during an investigation of the littoral Enchytraeidae of the coasts of Anglesey and the Menai Straits, twelve species of enchytraeid new to the British Isles and one species new to science were identified. The new species, a member of the genus Lumbricillus Ørsted 1844, is hereby named Lumbricillus christenseni, after Dr Bent Christensen of the University Zoological Museum, Copenhagen, in recognition of his contribution to our knowledge of enchytraeid taxonomy.Lumbricillus christenseni sp.nov.Location and habitatThis worm has been found in only one location, namely, Porth Eilian, a small bay at the north-east corner of the island of Anglesey, North Wales. The worm was most common at about high-water mark of the neap tide, in a mixture of sand and pebbles with a sparse covering of undecayed weed. The specimens examined were all taken within 5 cm of the surface. There was a large proportion of mature specimens at the time of collection, that is, late spring and early summer of 1964.

Enchytraeus fragmentosus , a New Species of Naturally Fragmenting Oligochaete Worm

A new species of enchytraeid (Oligochaeta) worm has no sex organs, but reproduces solely by fragmentation.

Enchytraeus fragmentosus, a New Species of Naturally Fragmenting Oligochaete Worm

A new species of enchytraeid (Oligochaeta) worm has no sex organs, but reproduces solely by fragmentation.