Lumbricid Earthworms Research Articles

Lumbricid earthworm invasion in the Carpathian Mountains and some other sites in Romania

Recent field research shows that the ubiquitous Lumbricus terrestris and Octolasion lacteum (the large parthenogenetic form) have invaded new habitats in Romania, replacing mostly endemic or rare species of the former earthworm communities which were recorded 20–30 years ago. Seven different cases of earthworm invasion are currently described. Invader species have larger ecological tolerances as compared with the endemic species.

An annotated checklist of the earthworm fauna of Turkey (Oligochaeta: Lumbricidae)

A checklist of the Lumbricid earthworms in Turkey is presented. Each entry is accompanied by complete references and, where it is appropriate, remarks are also added. The present list consists of 66 species of which 24 spp. (36.4%) seem to be Anatolian endemics. This indicates a highly specialized earthworm fauna predominated by the representatives of the genera Healyella Omodeo & Rota, 1989 and Dendrobaena Eisen, 1874.

Transmission of Nephridial Bacteria of the EarthwormEisenia fetida

The lumbricid earthworms (annelid family Lumbricidae) harbor gram-negative bacteria in their excretory organs, the nephridia. Comparative 16S rRNA gene sequencing of bacteria associated with the nephridia of several earthworm species has shown that each species of worm harbors a distinct bacterial species and that the bacteria from different species form a monophyletic cluster within the genus Acidovorax, suggesting that there is a specific association resulting from radiation from a common bacterial ancestor. Previous microscopy and culture studies revealed the presence of bacteria within the egg capsules and on the surface of embryos but did not demonstrate that the bacteria within the egg capsule were the same bacteria that colonized the nephridia. We present evidence, based on curing experiments, in situ hybridizations with Acidovorax-specific probes, and 16S rRNA gene sequence analysis, that the egg capsules contain high numbers of the bacterial symbiont and that juveniles are colonized during development within the egg capsule. Studies exposing aposymbiotic hatchlings to colonized adults and their bedding material suggested that juvenile earthworms do not readily acquire bacteria from the soil after hatching but must be colonized during development by bacteria deposited in the egg capsule. Whether this is due to the developmental stage of the host or the physiological state of the symbiont remains to be investigated.

Valosine-containing proteins (VCP ) in an annelid: Identification of a novel spermatogenesis related factor

Two cDNAs similar to mammalian valosine-containing proteins (VCPs) were isolated from the common lumbricid earthworm Eisenia fetida (Savigny, 1826). The primary sequences, referred to as eVCP-1 and eVCP-2, display a similarity of 74%. Despite of the variable C-termini, both eVCPs have a conserved intron/exon organization spanning 14 kb, which is also conserved to their mammalian counterparts. Although this finding strongly suggests VCPs have a common ancestral origin, phylogenetic analysis predicts that eVCP-2 may be distinct. An investigation by reverse transcription-polymerase chain reaction (RT-PCR) revealed that, whilst evcp-1 was ubiquitously expressed during all developmental stages, evcp-2 was specifically expressed in the anterior segments of sexually mature earthworms. In situ hybridization clearly demonstrated that evcp-2 is expressed in the seminal vesicles, the location of spermatogenesis, and more precisely within the cytophores surrounded by secondary spermatocytes or spermatids. Taken together, this evidence leads to the notion that eVCP-2 is a likely component involved in the final modulation of spermatogenesis.

First record of Dendrobaena pygmaea (Oligochaeta: Lumbricidae) from Asia (Yokohama, Japan)

The 'cosmopolitan' lumbricid earthworm Dendrobaena pygmaea (Savigny, 1826) is reported for the first time from Asia, from the campus of Yokohama National University, Japan. It is a small detritivorous 'litter species' or 'humus feeder' found to have a simple intestinal typhlosole. Here it is briefly re-described, and its taxonomy and previously known distribution (in Europe, North Africa, North and South America) are discussed. A figure is provided. As Yokohama port was opened for foreign trade shortly after Commodore Perry's visit in 1853, the incursion of this species is probably only within the last 150 years. It is not considered to pose any particular environmental risk.

Dual stable isotope analysis (δ 13C and δ 15N) of soil invertebrates and their food sources

More research is required to validate and refine natural abundance stable isotope ratio techniques as a tool for the investigation of the feeding ecology of soil animals and trophic relations in soil food webs. Isotope ratios of C (δ 13C) and N (δ 15N) were measured in herbivorous and detritivorous invertebrate groups, namely lumbricid earthworms (7 species), enchytraeid worms (3 species), slugs (3 taxa), and their potential food sources in an arable system. Intrapopulation δ 15N variation in the slug Deroceras reticulatum ( n=52) was large (range 4.2‰), possibly reflecting spatial variability in the food sources. Significant correlations between C:N ratios and isotope ratios in earthworms suggest that factors other than feeding may influence isotopic patterns. One enchytraeid species, Enchytraeus buchholzi, was enriched in 13C and strongly depleted in 15N compared to all other groups. Invertebrates formed a continuum when considered in relation to C and N separately, but fell into two distinct groups on the basis of combined C and N isotope ratios. The less enriched group represents herbivorous and litter-feeding species, while the more enriched group represents soil feeders. It is concluded that δ 13C measurements could provide a means of assigning separate baseline δ 15N values to primary and secondary decomposers, which in turn could improve the inference of higher trophic levels, omnivory and intraguild predation.

Pesticide-induced surface migration by lumbricid earthworms in grassland: life-stage and species differences

Pesticide-induced changes in surface migration by earthworms in grassland were investigated using trapping and the fungicide benomyl. Traps were tended daily for 15 days after spraying, resulting in 2152 earthworms, five species, and juvenile predominance which reflected species/life-stage composition in the soil. Significant increases in migration (all worms) occurred already by day 2 due to spraying, final treatment level being 2.8× control. Life-stage composition indicated an increased juvenile proportion from 55% to 75% due to treatment. Spraying caused surfacing juveniles to increase significantly by day 2, reaching a final level 3.8× control, whereas for mature worms a significant increase did not occur until day 4. Species rank-order was Aporrectodea longa> A. rosea> Lumbricus terrestris> A. caliginosa in control areas, but A. longa> L. terrestris> A. rosea> A. caliginosa in sprayed areas; spraying altered the rank-order such that the anecic A. longa and L. terrestris dominated, jointly increasing from 59% to 78%. At species level, L. terrestris and A. longa exhibited significant increases of 4.6× and 3.6× in final migration levels in treated areas, the endogeic A. rosea and A. caliginosa having trends for increase. Species-specific differences for reaction time occurred, with significantly elevated migration already by day 1 for L. terrestris, and day 2 for A. longa and A. caliginosa. For each species, juveniles consistently showed greater increases than mature worms due to spraying, significantly so for juvenile L. terrestris, A. longa, and A. caliginosa, the two anecics reaching as high as 5.3× and 4.7×. The response of mature worms differed: A. longa and A. rosea increased surfacing due to treatment, L. terrestris showed a delayed reaction, whereas A. caliginosa exhibited suppressed migration. Results are discussed relative to behavior, ecological category, and risk of toxic exposure.

Uniparental reproduction of Eisenia fetida and E. andrei (Oligochaeta: Lumbricidae): evidence of self-inseminationThe 7th international symposium on earthworm ecology · Cardiff · Wales · 2002

Summary This study investigated the copulatory behaviour of the lumbricid earthworm Eisenia fetida (Savigny, 1826) in a natural population, and the uniparental reproduction of E. fetida and E. andrei Bouche 1972, two closely-related species. Sperm transfer occurred in 61% of the matings observed, of which 88.2% showed bi-directional sperm transfer, 9.8% unidirectional sperm transfer and one earthworm was self-inseminating. Although uniparental reproduction in earthworms has been reported by many authors, self-insemination has never been recorded before this study. Moreover, specimens of the two species were reared in isolation from hatching to see if they were able to produce cocoons when clitellate. The percentage of earthworms that produced cocoons was significantly higher in E. andrei (33%) than in E. fetida (3.5%). Numbers of cocoon produced and the number of hatchlings per cocoon were also significantly higher in E. andrei than in E. fetida ; the cocoon viability was similar in the two species. One of these isolated individuals of E. fetida that produced cocoons was dissected and sperm was found into the spermathecae, indicating that self-insemination could be responsible, to some extent, of uniparental reproduction. Since parthenogenesis has not been demonstrated in these species, further studies are needed to show if uniparental reproduction is due only to self-fertilization.

Uniparental reproduction of Eisenia fetida and E. andrei (Oligochaeta: Lumbricidae): evidence of self-insemination : The 7th international symposium on earthworm ecology · Cardiff · Wales · 2002

Summary This study investigated the copulatory behaviour of the lumbricid earthworm Eisenia fetida (Savigny, 1826) in a natural population, and the uniparental reproduction of E. fetida and E. andrei Bouche 1972, two closely-related species. Sperm transfer occurred in 61 % of the matings observed, of which 88.2 % showed bi-directional sperm transfer, 9.8 % unidirectional sperm transfer and one earthworm was self-inseminating. Although uniparental reproduction in earthworms has been reported by many authors, self-insemination has never been recorded before this study. Moreover, specimens of the two species were reared in isolation from hatching to see if they were able to produce cocoons when clitellate. The percentage of earthworms that produced cocoons was significantly higher in E. andrei (33 %) than in E. fetida (3.5 %). Numbers of cocoon produced and the number of hatchlings per cocoon were also significantly higher in E. andrei than in E. fetida; the cocoon viability was similar in the two species. One of these isolated individuals of E. fetida that produced cocoons was dissected and sperm was found into the spermathecae, indicating that self-insemination could be responsible, to some extent, of uniparental reproduction. Since parthenogenesis has not been demonstrated in these species, further studies are needed to show if uniparental reproduction is due only to self-fertilization.

RDNA (18S-28S and 5S) Colocalization and Linkage Between Ribosomal Genes and (TTAGGG)n Telomeric Sequence in the Earthworm, Octodrilus complanatus (Annelida: Oligochaeta: Lumbricidae), Revealed by Single- and Double-Color FISH

Spermatogonial and metaphase I chromosomes of the lumbricid earthworm Octodrilus complanatus (Annelida: Oligochaeta) were examined using fluorescent in situ hybridization (FISH) with three repetitive DNA probes-5S rDNA, 18S-26S rDNA, and (TTAGGG)(n). Single-color FISH consistently mapped one chromosome pair per spread using either 5S rDNA or 18S-26S rDNA as probes. Simultaneous (18S-26S)-5S and (18S-26S)-(TTAGGG)(n) FISH demonstrated that repeated units of the two ribosomal families were overlapped and closely associated with telomeric sequences.

Observations on Feeding Behavior by the Terrestrial Flatworm Bipalium adventitium (Platyhelminthes: Tricladida: Terricola) from Illinois

Abstract Bipalium adventitium Hyman, 1943, an exotic terrestrial flatworm that is predatory on earthworms, is reported from Illinois for the first time. No-choice laboratory feeding tests were performed to test the acceptability of several lumbricid earthworm species as prey for B. adventitium and to compare the mass gained by B. adventitium in feeding bouts on different species of lumbricid earthworms. All species of earthworms (Allolobophora chlorotica (Savigny, 1826), Aporrectodea rosea (Savigny, 1826), Ap. turgida (Eisen, 1874), Eisenia fetida (Savigny, 1826) and Octolasion tyrtaeum (Savigny, 1826)) presented to B. adventitium were attacked and consumed. Allolobophora chlorotica, Aporrectodea rosea and Eisenia fetida are added to the list of potential prey species of earthworms in North America. Bipalium adventitium readily attacked and fed on earthworms up to 55 times larger than themselves in mass and they gained 52% of their prefeeding live mass during feeding bouts. Prefeeding live mass of flatwor...

Earthworm excreta attract soil springtails: laboratory experiments on Heteromurus Nitidus (Collembola: Entomobryidae)

Microarthropods are often found more abundantly in soils with earthworms than in soils without. Earthworms probably create a favourable environment for microarthropods but few studies have aimed to explain this earthworm effect. The soil collembolan (Hexapoda) Heteromurus nitidus, living in soils at pH>5 only and thus rich in earthworms, is particularly attracted by earthworms in humus cores. The effect of earthworms on the distribution of H. nitidus can be mediated either by direct contact or by odour perception. Two experimental designs were used to determine the pathway of attraction. The first set of experiments studied the effect of direct contact with earthworm excreta on the distribution of H. nitidus. The mixture of urine and mucus of the lumbricid earthworms Aporrectodea giardi and Alollobophora chlorotica significantly attracted H. nitidus as compared to deionized water while fresh earthworm casts were not preferred to calcic mull made of older casts. The same experiment involving direct contact with mucus and methyl blue showed that Collembola sucked on mucus/urine, indicating that the interaction of Collembola and earthworms was at least partly trophic. The second experiment demonstrated that H. nitidus was attracted by the odour of Aporrectodea giardi at short distance. The odour of excreta (mucus, urine and casts) of Aporrectodea giardi also attracted H. nitidus but this attraction was weaker and did not occur constantly, possibly due to interactions with light and aggregation pheromones. We conclude that the prominent pathway by which earthworms could attract H. nitidus in the field is through direct contact with earthworm mucus and urine. The acid-intolerant distribution of this species in the field could be partly explained by a trophic interaction with some earthworm species.

The Potential Impact of the New Zealand Flatworm, a Predator of Earthworms, in Western Europe

The New Zealand flatworm Arthurdendyus triangulatus (=Artioposthia triangulata) is an example of an invasive organism that, by reducing lumbricid earthworm populations, could have a major impact on soil ecosystems in Britain and the Faroe Islands. How it was introduced into the British Isles is not known, but like many invasive species, it is suspected that it was introduced by humans and was associated with the trade between New Zealand and Britain. Once established in Britain it found in the large, readily available earthworm population a niche that it could exploit. The microclimate of the forests in the center and south of the South Island of New Zealand from whence the flatworm came is similar to that in parts of the British Isles and consequently conducive to its survival. Although when compared with many other invertebrate introductions (e.g., insects) the flatworm's rate of increase has been slow, a retrospective study strongly suggested that, in Scotland, they spread from botanic gardens to horticultural wholesalers, then to domestic gardens, and only latterly did they invade agricultural land. As with other invasive species, the application of the CLIMEX computer model and geographic-information-system techniques have been used to try to ascertain its potential distribution within both the British Isles and Europe. The data suggest that A. triangulatus could become established in northwest continental Europe, and Denmark, Iceland, and Sweden have added it to their quarantine pest lists. The fact that A. triangulatus is the only one of 12 alien terrestrial planarians in Britain to be considered a pest suggests that this group of invertebrates is behaving in a fashion similar to other invasive organisms and obeys the “tens rule” suggested by M. Williamson. Since within the period 1995–1997 another three species of predatory terrestrial planarians have been recorded in Scotland it is evident that the existing phytosanitary regulations must be more strongly enforced or new ones introduced if the spread of terrestrial planarians is to be halted. For reprints of this Invited Feature, see footnote 1, p. 1259.

THE POTENTIAL IMPACT OF THE NEW ZEALAND FLATWORM, A PREDATOR OF EARTHWORMS, IN WESTERN EUROPE

The New Zealand flatworm Arthurdendyus triangulatus (=Artioposthia triangulata) is an example of an invasive organism that, by reducing lumbricid earthworm populations, could have a major impact on soil ecosystems in Britain and the Faroe Islands. How it was introduced into the British Isles is not known, but like many invasive species, it is suspected that it was introduced by humans and was associated with the trade between New Zealand and Britain. Once established in Britain it found in the large, readily available earthworm population a niche that it could exploit. The microclimate of the forests in the center and south of the South Island of New Zealand from whence the flatworm came is similar to that in parts of the British Isles and consequently conducive to its survival. Although when compared with many other invertebrate introductions (e.g., insects) the flatworm's rate of increase has been slow, a retrospective study strongly suggested that, in Scotland, they spread from botanic gardens to horticultural wholesalers, then to domestic gardens, and only latterly did they invade agricultural land. As with other invasive species, the application of the CLIMEX computer model and geographic-information-system techniques have been used to try to ascertain its potential distribution within both the British Isles and Europe. The data suggest that A. triangulatus could become established in northwest continental Europe, and Denmark, Iceland, and Sweden have added it to their quarantine pest lists. The fact that A. triangulatus is the only one of 12 alien terrestrial planarians in Britain to be considered a pest suggests that this group of invertebrates is behaving in a fashion similar to other invasive organisms and obeys the “tens rule” suggested by M. Williamson. Since within the period 1995–1997 another three species of predatory terrestrial planarians have been recorded in Scotland it is evident that the existing phytosanitary regulations must be more strongly enforced or new ones introduced if the spread of terrestrial planarians is to be halted. For reprints of this Invited Feature, see footnote 1, p. 1259.

Prosellodrilus doumandjiin. sp., a new lumbricid from Algeria

A new species of lumbricid earthworm, Prosellodrilus doumandjii, is described from Birtouta (Mitidja plain, Algeria). Similarities and differences with related taxa are discussed, and it is suggested splitting the genus Prosellodrilus Bouche 1972 into two subgenera: the nominal one, including the species living in southwestern France, and a new subgenus inhabiting Maghreb and Sardinia. The name Maghrebiella is proposed for the latter new taxon. The biogeographic connections between Maghreb earthworms and those living in central and western Mediterranean countries are discussed. KEY WORDS: Mitidja, Algeria, Lumbricidae, Maghreb earthworms, Prosellodrilus, Maghrebiella new subgenus, West Mediterranean zoogeography.

Quantification of nitrogen excretion rates for three lumbricid earthworms using 15 N

Nitrogen excretion rates of 15 N-labeled earthworms and contributions of 15 N excretion prod- ucts to organic (dissolved organic N) and inorganic (NH4-N, NO3-N) soil N pools were determined at 10 7C and 18 7C under laboratory conditions. Juvenile and ad- ult Lumbricus terrestris L., pre-clitellate and adult Aporrectodea tuberculata (Eisen), and adult Lumbricus rubellus (Hoffmeister) were labeled with 15 N by pro- viding earthworms with 15 N-labeled organic substrates for 5-6 weeks. The quantity of 15 N excreted in unla- beled soil was measured after 48 h, and daily N excre- tion rates were calculated. N excretion rates ranged from 274.4 to 744 mg N g -1 earthworm fresh weight day -1 , with a daily turnover of 0.3-0.9% of earthworm tissue N. The N excretion rates of juvenile L. terrestris were significantly lower than adult L. terrestris, and there was no difference in the N excretion rates of pre- clitellate and adult A. tuberculata. Extractable N pools, particularly NH4-N, were greater in soils incubated with earthworms for 48 h than soils incubated without earthworms. Between 13 and 40% of excreted 15 N was found in the 15 N-mineral N (NH4-NcNO3-N) pool, and 13-23% was in the 15 N-DON pool. Other fates of excreted 15 N may have been incorporation in microbial biomass, chemical or physical protection in non-ex- tractable N forms, or gaseous N losses. Earthworm ex- cretion rates were combined with earthworm biomass measurements to estimate N flux from earthworm pop- ulations through excretion. Annual earthworm excre- tion was estimated at 41.5 kg N ha -1 in an inorganically- fertilized corn agroecosystem, and was equivalent to 22% of crop N uptake. Our results suggest that the earthworms could contribute significantly to N cycling in corn agroecosystems through excretion processes.

Changes in soil fauna and soil conditions under Pinus radiata agroforestry regimes during a 25-year tree rotation

Pinus radiata was planted in a grazed pasture at Tikitere, New Zealand in 1973; final tree stocking rates were 0, 50, 100, 200 and 400 stems ha–1; trees were harvested in 1999. We sampled the loamy sand for chemistry, earthworms, enchytraeids and nematodes during crop growth. There were no visible changes in the soil profile between years 2 and 25 of the P. radiata rotation, but marked changes in soil chemistry with pH declining at all depths. Topsoil pH declined but plant-available P and the soil C : N ratio increased. That similar trends occurred in pasture may have reflected reduced inputs. Lumbricid earthworms declined with increasing time and tree stocking rate; significant populations were found only in pasture at 25 years; no related changes in soil bulk density were detected. Enchytraeids were abundant but declined in the plots with 200 and 400 stems ha–1. The composition of the nematode fauna at a soil depth of 0–10 cm varied, and there were changes in the “control” pasture. Pratylenchus sp. and Pungentus sp. were characteristic of pasture;Diphtherophora sp. appeared at higher tree stocking rates. In addition to changes related to the change in landuse there were temporal changes that affected faunal composition across tree stocking rates: Heterodera sp. and Paratylenchus sp. were rare after year 6;Prismatolaimus sp. was most abundant in years 2, 13 and 25;Axonchium sp. occurred in year 6 and Alaimus sp. mainly in year 25. Overall, the changes in soil chemistry reflected the change from pasture to forest. Parallel changes in soil microfauna and macrofauna also reflected the change in landuse, from fertilised pasture to coniferous forest, and are considered reversible.

A method of extracting earthworms from cores of soil with minimum damage to the soil

Lumbricid earthworms have often been shown to increase the growth of plants. The earthworms and plants were generally grown together in the same soil, although sometimes earthworms were reluctant to enter the soil. It was not possible to isolate the mechanism for the increased growth, as no method was available to extract the earthworms with no damage to the soil before the plants were grown. A method is described which enabled Aporrectodea caliginosa, but not A. trapezoides, to enter all cores, and which extracted A. caliginosa from the cores probably with minimum damage to the soil.

Possible functions of oxytocin/vasopressin-superfamily peptides in annelids with special reference to reproduction and osmoregulation.

Annetocin is an earthworm oxytocin-related peptide that we previously isolated from the whole body of a lumbricid earthworm Eisenia foetida. We have reported that annetocin induces egg-laying-like behaviors in E. foetida and a gnathobdellid leech, Whitmania pigra, when it is injected into the respective animals. The present study was undertaken to probe physiological functions of invertebrate oxytocin-vasopressin-superfamily peptides with special reference to reproductive and osmoregulatory events in which vertebrate peptides of this superfamily are involved. Annetocin, Lys-conopressin (a leech vasopressin-related peptide) and two analog peptides, [Tyr(3)]-annetocin ((3)Y-annetocin) and [Phe(3)]-annetocin ((3)F-annetocin), were compared for their activities to induce egg-laying-like behavior and to change body weight as a measure of water balance in the leech W. pigra. Injection of annetocin, Lys-conopressin, and (3)F-annetocin caused both egg-laying-like behavior and reduction of body weight in the animals, but (3)Y-annetocin induced neither. Furthermore, leeches in the non-breeding season responded to peptides less conspicuously than those in the breeding season. Such a concomitant induction of egg-laying-like behavior and body-weight reduction suggests that these two phenomena are unitary and might be accounted for by the fact that egg-laying in leeches and earthworms is accompanied by secretion of a large quantity of mucus, which should significantly contribute to body-weight loss. J. Exp. Zool. 284:401-406, 1999.

Species abundance of earthworms in arable and pasture soils in south-eastern Australia

Earthworms play an important role in soil ecology and can serve as practical indicators in land quality evaluation. The abundance and distribution of earthworms were determined in 84 cropping and pasture soils in north-east Victoria and southern New South Wales (NSW), Australia. Overall, an average density of 89 earthworms m −2 was found, with an average species richness of 1–2 per site, indicating relatively low abundance and species poverty. Introduced lumbricid earthworms, Aporrectodea trapezoides and A. caliginosa were the most widely distributed (88% and 61% of all sites, respectively) and numerically dominant (respective population densities of 35.8 and 32.1 m −2). Soils under pasture supported on average 3.2 times more earthworms than those under cropping. The age structure of populations varied with species, introduced lumbricids and acanthodrilids displayed an adult-dominant structure and the native megascolecids displayed a juvenile-dominant population. Indigenous earthworms belonged to a single genus, Spenceriella. Whilst not occurring in high densities these indigenous earthworms were widespread in their distribution and their numbers were negatively correlated with soil P, K, and Mg suggesting an adaptation to low levels of soil fertility. Although the relationship between earthworm densities and mean annual total precipitation (MATP) was not close ( r 2 = 0.35), of the 33 sites containing >100 earthworms m −2, 25 received MATP in excess of 600 mm. Correlations between earthworm densities and a range of physical and chemical parameters were generally poor. This may highlight the short-comings of these parameters in describing distribution patterns.