Applied Soil Ecology 14 2000 17–26
Microfungal communities in soil, litter and casts of Lumbricus terrestris L. Lumbricidae: a laboratory experiment
Alexei V. Tiunov
a,∗
, Stefan Scheu
b
a
Laboratory of Soil Zoology, Institute of Ecology and Evolution, Leninsky Prospect 33, 117071, Moscow, Russia
b
Institute of Zoology, Darmstadt University of Technology, Schnittspahnstrasse 3, D-64287, Darmstadt, Germany Received 8 July 1999; received in revised form 29 November 1999; accepted 1 December 1999
Abstract
The anecic earthworm Lumbricus terrestris L. was kept in laboratory microcosms containing beech forest soil without litter, with beech leaf litter or with lime leaf litter. The structure of microfungal communities in soil, litter and fresh and aged
100 days earthworm faeces was analysed using the washing and plating technique. The passage of mineral soil through the gut of L. terrestris affected the structure of the fungal community only little. In contrast, in the litter treatments the structure
of the fungal community in fresh earthworm casts significantly differed from that in soil and litter. The majority of soil and litter inhabiting fungi survived passage through the gut of L. terrestris and the fungal community in casts consisted of a
mixture of soil and litter inhabiting fungi. However, the frequency of Cladosporium spp., Alternaria spp., Absidia spp., and other taxa was strongly reduced in fresh casts. The degree of colonization of litter particles number of isolates per number
of plated particles also decreased, but some fungi mainly Trichoderma spp. benefited from gut passage and flourished in fresh casts. During ageing of cast material the dominance structure of the fungal community changed. Both the degree of
colonization of organic particles and the species diversity increased and approached that in soil. However, the structure of the fungal community in casts remained cast specific even after 100 days of incubation. It is concluded that the feeding and
burrowing activity of L. terrestris accelerates the colonization of litter by the edaphic mycoflora but also extends the range of occurrence of litter-associated fungi into mineral soil layers. ©2000 Elsevier Science B.V. All rights reserved.
Keywords: Soil fungi; Fungal community; Anecic earthworms; Lumbricus terrestris; Litter decomposition
1. Introduction
Fungi and earthworms are important members of soil communities and their interactions are assumed
to significantly affect microbial-mediated processes in soil. Although the importance of these interactions
is widely accepted, they are little studied and the in- formation available is in part contradictory Brown,
1995. Earthworms may influence soil fungi by a
∗
Corresponding author. Tel.:+7-095-958-1449; fax: +7-095-954-5534952-2592.
E-mail address: zoosoilorc.ru A.V. Tiunov.
variety of mechanisms, including the alteration of the physical and chemical state of the environment ‘en-
gineering’ sensu Jones et al., 1997, comminution and translocation of litter, dispersal of fungal propagules
and grazing on fungal tissue Visser, 1985. Various authors suggested that fungi are a major component of
the diet of earthworms Dash et al., 1984, 1986; Ed- wards and Fletcher, 1988; Tiwari et al., 1990; Doube
and Brown, 1998. Earthworms have been shown to prefer food substrates colonized by certain fungal
species and fungi have been found to be damaged by gut passage Cooke, 1983; Moody et al., 1995, 1996;
Marfenina and Ishchenko, 1997.
0929-139300 – see front matter ©2000 Elsevier Science B.V. All rights reserved. PII: S 0 9 2 9 - 1 3 9 3 9 9 0 0 0 5 0 - 5
18 A.V. Tiunov, S. Scheu Applied Soil Ecology 14 2000 17–26
Even low levels of selective grazing by invertebrates has been shown to significantly alter the distribution
and succession of fungi on litter Parkinson et al., 1979; Newell, 1984. Therefore, it is likely that earth-
worms alter the composition of fungal communities in soil and the fungal succession in decomposing lit-
ter. However, there is only fragmentary information on effects of earthworms on the structure of fungal com-
munities in soil. Domsch and Banse 1972 reported a strong alteration of the fungal dominance structure in
casts of Lumbricus terrestris in comparison to the food substrates. In contrast, Tiwari and Mishra 1993 did
not find significant differences in the structure of fun- gal communities in soil and field-collected earthworm
casts. In micro- and mesocosm experiments, the pres- ence of the epigeic earthworm species Dendrobaena
octaedra McLean and Parkinson, 1998 and the endo- geic species Octolasion tyrtaeum Scheu and Parkin-
son, 1994 affected the structure of fungal communi- ties only little, although the frequency of some species
changed significantly. Detailed studies aiming at sep- arating different mechanisms which may contribute
to earthworm-mediated changes in the structure of fungal communities in soil are lacking.
We studied microfungal communities in fresh and aged faeces of the widespread anecic earthworm L.
terrestris L. This large deep-burrowing species builds permanent vertical burrows, but feeds mainly on or-
ganic materials on the soil surface. Due to the feeding and burrowing activity of L. terrestris, large amounts
of mineral soil are translocated upward to the soil sur- face and mixed with litter, whereas litter material is
transferred deep into the mineral soil. We addressed the following questions: how does passage through the
gut of L. terrestris affect the structure of the fungal community as compared to soil and litter? Which of
the soil and litter inhabiting fungal species survive, and which are damaged by gut passage? How does the
fungal community in faeces change during ageing of cast material?
2. Materials and methods
