Aerobically isolated bacteria associated with the gut and faeces of the litter feeding macroarthropods Oniscus asellus and Glomeris marginata

Bacteria were isolated from the food, guts and faeces of the litter feeding macroarthropods Oniscus asellus and Glomeris marginata. Bacterial counts showed that bacterial growth was enhanced both in the guts and faeces of these animals.Significant differences in the biochemical capabilities of the isolates derived from litter, gut populations and faeces were noted, with the ability to grow facultatively anaerobically being associated with gut and faecal populations. Similarly, the ability to degrade uric acid was a common attribute of the faecal isolates from both macroarthropods.The results suggest that grazing by soil animals can cause a marked increase in litter bacterial activity even in acid soils, where fungi normally dominate decomposer activity.     

Micro-organisms and metal retention in the woodlouse Oniscus asellus

Claims by other authors as to the importance of coprophagy and micro-organisms in copper uptake by terrestrial isopods are largely unsubstantiated. This paper describes an expriment which shows that, at least in Oniscus asellus, Cu and Zn and rapidly assimilated irrespective of coprophagy. In contrast, Cd and Pb were not rapidly assimilated although Cd was more readily retained by animals not able to resort to coprophagy. Numbers of bacteria and fungi in the food supply and in both guts and faeces of O. asellus are related to animal activity and corophagy. Numbers of bacteria in faeces are higher than in original litter suggesting a stimulation during passage through the gut, in comparison numbers of fungi show the reverse. In the absence of corophagy numbers of micro-organisms are reduced in the litter, presumably by increased grazing. he ratio of actinomycetes: bacteria in the animal gut ranges from 0.024 to 0.247 and this ratio is affected by both corophagy and the food supply. The metal tolerance of the gut microflora increases as result of feeding on litter contaminated with metals, but is also affected by coprophagy. Although the association of micro-organisms in the feeding strategy of terrestrial isopods still requires a great deal of research it is suggested that actinomycetes could be of importance in the nutrition, and ultimately metal concentration, of O. asellus.     

The biochemical transformation of oak (Quercus robur) leaf litter consumed by the pill millipede (Glomeris marginata)

Soil macrofauna play an essential role in the initial comminution and degradation of organic matter entering the soil environment and yet the chemical effects of digestion on leaf litter are poorly understood at the molecular level. This study was undertaken to assess the selective chemical transformations that saprophagous soil invertebrates mediate in consumed leaf litter. A number of pill millipedes (Glomeris marginata) were fed oak leaves (Quercus robur) after which the biomolecular compositions (lipids and macromolecular components) of the leaves and millipede faeces were compared using a series of wet chemical techniques and subsequent analysis by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS). It was found that the concentrations of short chain (<C₂₀) n-alkanoic acids, sterols and triacylglycerols reduced dramatically in the millipede faeces relative to the leaf litter. Hydrolysable carbohydrates and proteins both decreased in concentration in the faeces, whereas similar yields of phenolic components were observed for the cupric oxidation products of lignin, although the oxygenated functionalities were affected by passage through the millipede gut, yielding a more highly condensed state for lignin. This shows that the chemical composition of fresh organic matter entering the soil is directly controlled by invertebrates feeding upon the leaf litter and as such that they are key contributors to the early stages of diagenesis in terrestrial soils.     

Effects of soil invertebrates on the survival of some genetically engineered bacteria in leaf litter and soil

Seven bacterial strains, most of them bearing natural or recombinant plasmids, were introduced in oak leaf litter or soddy-podzolic soil. In these substrata, which contained litter-dwelling diplopods and isopods, or endogenic earthworms, bacteria survival was followed. In the absence of the animals, the numbers of introduced strains gradually decreased. In the presence of the animals, plasmid-bearing strains of Pseudomonas putida survived at 10⁵–10⁷ CFUs g^-1 up to 1.5 months in both leaves and soil. The total numbers of bacteria found in excrements from the soil macrofauna were 5–15 times higher than in the food. The numbers of P. putida in the excrements were equal to or higher than in the food. The numbers of Pseudomonas stutzeri JM302 (pLV1013) and Azospirillum brasiliense ATCC29710 (pFACII) in the excrements were always 2–10 times lower than in the food. The digestive fluid taken from the middle part of the gut of the diplopod Pachyiulus flavipes showed a strong antibacterial activity. Those bacteria with lower survival in the gut appeared to be more sensitive to digestion by the midgut fluid. In contrast, the hindgut fluid did not suppress the viability of P. stutzeri JM302 (pLV1013). We postulate that the introduced bacteria partially survive the midgut passage and then multiply with a high growth rate in the hindgut of the animals. The environmental consequences of the interactions between soil invertebrates and the released bacteria are discussed.Dedicated to Professor J. C. G. Ottow on the occasion of his 60th birthday     

Vertical distribution of Collembola (Hexapoda) and their food resources in organic horizons of beech forests

 Micro-samples of the surface organic horizons of 13 beech forests in Belgium were fixed immediately after collection in ethanol. Collembola (6255 animals) were sorted directly from micro-samples in the laboratory using a dissecting microscope, while the litter/soil matrix was analysed semi-quantitatively. The vertical distribution of Collembolan species was studied by correspondence analysis. Gut contents of animals were examined under a light microscope and their composition was compared with that of the matrix. A consistent association was found between the vertical distribution of gut contents and that of food resources in the immediate proximity of animals. Species differed in their feeding habits but most of them ingested a wide spectrum of food items. Plasticity in the food regime according to depth could be demonstrated in members of the Onychiuridae family. Received: 11 January 1999     

Beech leaf degradation in laboratory experiments: Effects of eight detritivorous invertebrate species

This work addresses the impact of eight detritivorous species of soil macro-invertebrates (three millipedes, two woodlice and three earthworms) on short-term carbon mineralization and mechanical breakdown of beech leaves. The production rate, size class distribution and OM content of invertebrate faeces were also measured. Hierarchical clustering (HC) and multivariate analysis were performed to find relevant functional groups among the species studied.Our results identified three groups of macro-invertebrates on the basis of their impacts on beach leaf degradation (hierarchical clustering): (1) invertebrates that produce fresh faeces with high N contents compared with other species (i.e. polydesmidae and a single species of lumbricidae); (2) other lumbricidae that fragment litter into fine particles in their faeces and actively stimulate CO₂ release; (3) other arthropods that fragment litter into coarse particles and have weak impacts on OM mineralization. These groups over-ride taxonomy, and are proposed as a tentative functional classification of litter dwelling invertebrates. On the other hand, an idiosyncratic impact of species was observed in each group, highlighting how much empirical data are still needed to propose a robust functional classification of litter invertebrates.     

Role of soil mesofauna in dispersal of Coniothyrium minitans: mechanisms of transmission

Soil mesofauna are thought to play a role in the dispersal of Coniothyrium minitans Campbell but the mechanisms of transmission are unclear. The mite Acarus siro L. and the collembolan Folsomia candida Willem are known to be able to transmit the mycoparasite to uninfected sclerotia of Sclerotinia sclerotiorum (Lib.) de Bary in soil, and consequently the mechanisms of transmission of the mycoparasite by these animals have been investigated in detail. To facilitate this work, a novel method for surface sterilising mites was developed. In an initial investigation, A. siro was found to carry inoculum externally and in the gut. Indeed, almost all faecal pellets collected from either A. siro or F. candida, following feeding on C. minitans, contained germinable inoculum of the mycoparasite. Microscopic examination showed that faeces from these animals consisted mainly of conidia or fragments of conidium, but that only intact conidia gave rise to growth of C. minitans. Passage through the gut of either animal reduced percentage germination of conidia to 11 and 60% in mite and collembolan faeces, respectively, compared to 99% in controls not subjected to gut passage. In addition, germination in mite faeces was delayed by approximately 12 h compared to controls. However, subsequent germ tube extension from surviving conidia appeared unaffected by gut passage. Individual faecal pellets of A. siro were found to contain sufficient inoculum of the mycoparasite to initiate infection of sclerotia in moist sterile sand and non-sterile soil. The relevance of these results to the glasshouse and field situation is discussed.     

How does litter quality and site heterogeneity interact on decomposer food webs of a semi-natural forest?

The relative importance of litter quality and site heterogeneity on population dynamics of decomposer food webs was investigated in a semi-natural mixed deciduous forest in Denmark. Litterbags containing beech or ash leaves were placed in four plots. Plots were located within gaps and under closed canopies at two topographically different sites, above and below a slope, respectively, to cover variable environmental conditions. Litter was collected after 2, 4 and 9 months of decomposition. Extensive decay prevented analysis of ash after 9 months. Density of bacteria (CFU), active fungal mycelium (FDA), protozoa (MPN) and nematodes were 4-15-fold higher in ash leaves than in beech leaves in accordance with the higher resource quality of ash. Similar effects of site on density of decomposers were evident in both litter types: with some exceptions, decomposers were higher at the low site and stimulated in gaps. Taxonomic diversity of nematodes increased during decomposition and functional diversity of nematodes followed a pattern often encountered, i.e. opportunistic bacterial-feeders were gradually replaced by fungal-feeders and slower growing bacterial-feeders while predators and omnivors peaked at the end of the study period. At the first sampling, where bacterial activity prevailed, the relative abundance of the two dominant bacterial-feeders, Rhabditidae (fast growing) and Plectus spp. (slower growing), depended more on site than litter type. At the second sampling where fungal activity became more important, the proportions of bacterial and fungal-feeding nematodes also depended more on site than on litter type. At the third sampling individual nematode taxa responded differently to site. In summary, we conclude that although litter quality had a major influence on the density of organisms in the decomposer food web, site effects were also detected and nematode functional groups responded more to site than to litter quality early on in the decomposition process.     

Preliminary data about compartmentalization of the gut of the saprophagous dipteran larvae Penthetria holosericea (Bibionidae)

To describe the compartmentalization of the gut and the microbial activity in the digestive tract, the histology of the gut wall, enzymatic activity, pH of the gut content, abundance and composition of the microbial community (direct counts, plate counts on various media, and phospholipid fatty acid analyses—PLFA) were studied in the Penthetria holosericea larvae. The highest secretion activity was observed in the caeca and in the part of the anterior midgut before caeca openings. A strong increase in pH (10.5) was observed in the anterior part of the midgut. Some enzymes produced in the caeca might have their maximum activity in a different part of the gut as a result of their pH optimum; e.g. amylase was most active in the strongly alkaline anterior part of the mesenteron. Maltase, hydrolyzing products of starch degradation, was most active in the posterior part of the gut and in the ectoperithrophic space. The microbial community was reduced in the anterior part of the midgut. In the posterior part of the gut, bacterial numbers increased and peaked in excrements. Caeca had an abundant microbial community.     

Recycling of fecal pellets in isopods: Microorganisms and nitrogen compounds as potential food for Oniscus asellus L

The isopod Oniscus asellus was fed wood pieces. The fecal pellets produced during 6 days were reingested twice. Both fresh and ageing pellets were examined for microorganisms and nitrogen compounds including proteins and bacterial cell wall compounds, d-alanine and diaminopimelic acid. In old pellets, the plate counts of fungi decreased but that of bacteria as well as the concentrations of proteins and bacterial cell wall compounds increased from the first to the third gut passage. Immediately after a gut passage, the counts of microorganisms were lower than before the passage whereas the concentrations of bacterial cell wall compounds and proteins were higher. This indicates that both growth and lysis of bacteria occurred in the guts but that a considerable part of the bacterial cells were not digested and assimilated by the isopods. Comparison of the bacterial cell wall compounds also indicated shifts in the ratio of Gram-positive and Gram-negative bacteria during gut passages and during ageing of the fecal pellets. The concentration of total N did not markedly change after the second and third gut passages, indicating that the availability of N decreased due to accumulation of N into relatively recalcitrant proteins and bacterial cell walls.     

Short term and long term effects of bibionid (Diptera: Bibionidae) larvae feeding on microbial respiration and alder litter decomposition

Temporal changes of microbial respiration of leaf litter during gut passage by two species of bibionid flies (Penthetria holosericae and Bibio marci) and immediately after defecation were studied as well as the effect of B. marci feeding on microbial respiration in the remaining consumed leaf litter. Respiration in the guts of both species was lower than respiration of the original leaves. Microbial respiration increased after defecation, but respiration was higher in comparison with the original litter only for B. marci. Later, microbial respiration in both species decreased dramatically over several hours. Respiration of the remains of consumed leaves, from which the excrements were removed, was significantly higher than the respiration of non-consumed leaves. Scanning electron microscopy indicated that plant cells in the unconsumed part of the litter were massively broken-up by feeding activity and potentially exposed to microbial colonisation from the surrounding soil and microflora coming from the excrements deposited on the consumed litter. Long term (11 months) exposure of leaf litter and excrements produced from this litter showed that the decomposition of excrements was significantly slower than that of leaves. These findings indicate that bibionid feeding activity causes a short term increase in microbial mineralization of litter, but slows it down in the long term.     

Diet-related composition of the gut microbiota of Lumbricus rubellus as revealed by a molecular fingerprinting technique and cloning

Interactions between earthworms and microorganisms are essential for the functioning of soil ecosystems as they affect organic matter degradation and nutrient cycling. This is also true for the alpine region, where socio-economic changes lead to the increasing abandonment of pastures, which in turn, causes a considerable shift in the diet of saprotrophic invertebrates and thus impacts food web and decomposition processes. To enhance our understanding of how this diet shift influences earthworms and associated microorganisms, we studied the gut content and cast microbiota of Lumbricus rubellus (Lumbricidae, Oligochaeta), a key macrodecomposer on alpine pastureland in the Central Alps. A feeding experiment with L. rubellus and three different food sources that represent the vegetation shift from an alpine pasture to an abandoned site was set up. Earthworms were collected in the field, transferred to a climate chamber and fed with cow manure, dwarf shrub or grass litter for six weeks. PCR-DGGE (Polymerase chain reaction-denaturing gradient gel electrophoresis) analysis of the DNA extracted from the substrates, the earthworms' gut contents and casts revealed that the gut and cast microbiota was strongly influenced by the food source ingested. Cloning of bacterial 16S rRNA gene fragments demonstrated that the intestinal content was dominated by Proteobacteria, especially from the Gamma-subclass, followed by members of the phyla Bacteroidetes, Actinobacteria and Firmicutes. In contrast, Actinobacteria were detected abundantly in all samples types when a cultivation approach was used. In conclusion, the gut microbiota of L. rubellus was shown to be substantially affected by the food source ingested, suggesting that this essential macrodecomposer is exposed to the diet shift resulting from a land-use change in the alpine area.     

Major mechanisms contributing to the macrofauna-mediated slow down of litter decomposition

To understand why excrements of soil macrofauna often decompose more slowly than leaf litter, we fed Bibio marci larvae the litter of tree species differing in litter quality (Alnus glutinosa, Salix caprea, and Quercus robur) and then measured respiration induced by litter and excrements. We also measured respiration induced by the same litter artificially modified to mimic faunal effects; the litter was modified by grinding, grinding with alkalinization to pH = 11, grinding with coating by kaolinite, and grinding with both alkalinization and coating. Decomposition of excrements tended to be slower for willow and was significantly slower for oak and alder than for the corresponding litter. With oak, decomposition was slower for all artificially modified litter than for non-modified litter. The reduction in the decomposition was similar for excrements and for alder and willow litter that was ground, coated, and alkalinized. In alder, a similar reduction was found in ground and alkalinized litter. ¹³C NMR indicated that gut passage increases aliphatic components and decreases polysaccharides. Pyrolysis indicated that gut passage increases the ratio of guaiacyl to hydroxymethyl derivatives in lignin. Our findings indicate that the decreased decomposition rate of excrements might result from the removal of easily available polysaccharides, the increase in aliphatic components, an increase in the resistant components of lignin, the accumulation of microbial cell walls, and the binding of nitrogen into complexes with aromatic components. Several of these mechanisms are supported or determined by litter alkalinization during gut passage.     

Influence of macroarthropod feeding activities on microflora in decomposing oak leaves

Fragmented (2–4 mm) and mechanically ground (0.1–0.2 mm) oak litter was inoculated with faeces of Oniscus asellus or Glomeris marginata and incubated in the laboratory. After 40 days microbial respiration rates were the same for both litter treatments. Woodlice or millipedes were then added in various numbers and CO₂ evolution measured for a further 40 days.Microbial respiration in fragmented litter was initially increased to twice the control rates by four Oniscus and to 1.6 times control rates by six Glomeris but subsequently declined to rates slightly above controls. But in treatments with ten Oniscus respiration was depressed below the controls after 20 days. Cumulative CO₂ measurements showed that microbial respiration was inhibited by grazing pressures higher than optimum values.Animals feeding on previously-ground litter produced a similar, but reduced response, suggesting that litter comminution by the animals was the main factor contributing to the enhancement of C mineralization.Disturbance of fragmented litter, either by Oniscus or by mechanical means, produced no significant changes in respiration. In ground-litter cultures there was a small enhancement of CO₂ evolution for the first 10 days.Fungal standing crop was reduced to one-third of controls by Oniscus; the effects being particularly pronounced during the first 3 days of the experiment. Bacterial standing crop increased to a maximum of 10 times control levels.     

Climatic effects on soil trophic networks and the resulting humus profiles in holm oak (Quercus rotundifolia) forests in the High Atlas of Morocco as revealed by correspondence analysis

Multivariate methods have been widely used for revealing the structures of communities, and in this paper we explore one particular method, namely correspondence analysis (also called reciprocal averaging), for studying humus profiles by the ‘method of small volumes’. The present study was done on humus profiles under holm oak (Quercus rotundifolia), an evergreen Mediterranean species, in the High Atlas of Morocco. Three sites (1500 m, 1700 m, 1900 m altitude) and 2 years (1999 and 2002) were compared. The humus form is Dysmull (mull with thick litter horizons), with variations in the thickness of the OL (entire leaves), OF (fragmented leaves with faecal pellets) and A (hemorganic) horizons according to altitude and year. The dead leaves are rapidly incorporated into holorganic (earthworm, insect) and hemorganic (enchytraeid) animal faeces, which form the bulk of the OF and A horizons. The S horizon (weathering parent rock) shows the greatest development of the root system. As altitude increases more fresh litter (OL) or more humified organic matter (OF, A) is accumulated. Variation from year to year is depicted by opposite differences in the amount of entire oak leaves and of dead roots. Humus components (classes) are used as active (main) variables, after standardization of their means and variances. The addition of numerous passive (additional) variables, standardized in the same way as active variables, enabled us to understand the influence of biological and climatic effects on the composition of humus profiles and soil trophic networks.     

Microfungal communities in soil,litter and casts of Lumbricus terrestris L. (Lumbricidae): a laboratory experiment

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.     

印度西高止山脉森林中两类巨型丸状千足虫的食物及其排泄物的化学和微生物性质研究

Soil macroinvertebrates are highly diverse and their major ecological service include breakdown of organic matter and in turn improve soil fertility and pill-millipedes are well-known for their significant role in ingestion, disintegration and decomposition of organic matter in soil. This study characterized the feed, the decomposing leaf litter of coconut (Cocos nucifera), and faeces of two endemic giant pill-millipedes Arthrosphaera disticta and A. fumosa collected from forests of the Western Ghats of India based on chemical features and microbial profile. In both millipedes, electric conductivity and total phosphorus were significantly increased in faeces, while the crude protein, organic carbon, total nitrogen and total phenolics were significantly decreased,as compared to those in feed. Heterotrophic bacteria, actinomycetes, rhizobia and phosphate-solubilizing bacteria were significantly higher in faeces than in feed, while filamentous fungi and yeast substantially decreased in faces compared to feed in both the millipedes. Spectrum of fatty acid methyl esters was considerably different between feed and faeces of both the millipedes. The total saturated fatty acids were higher than the total unsaturated fatty acids in feed as well as faeces, while the ratio of unsaturated/saturated fatty acids decreased from feed to faeces. Dodecanoic and tetradecanoic acids in A. disticta and octadecanoic acid in A. fumosa significantly increased, while (9Z)-octadec-9-enoic and (9E,12E)-octadeca-9,12-dienoic acids in A. disticta and hexadecanoic, tetracosanoic and (9E,12E)-octadeca-9,12-dienoic acids in A. fumosa significantly decreased in faeces compared to feed, indicating millipede-dependent changes in fatty acids. Icosanoic acid was present in faeces of both the millipedes, and hexadec-9-enoic acid was confined to faeces of A. disticta, while pentadecanoic, heneicosanoic, (9Z,12Z,15Z)-9,12,15-octadecatrienoic and eicosenoic acids were confined to faeces of A. fumosa. Pill-millipedes enrich the soil quality by leaf litter conditioning in their gut through specific microbial communities. Fingerprinting of fatty acid methyl esters in faeces of these millipedes reflected the activity of specific microbial population in their guts.     

Accumulation and solubility of metals during leaf litter decomposition in non-polluted and polluted soil

The decomposition of alder ( Alnus glutinosa ) and poplar ( Populus tremula ) leaf litter placed in direct contact with non-polluted and metal-polluted soil was investigated over 25 months in a controlled model-ecosystem experiment using the litterbag method. In addition to mass loss, we monitored the total and soluble concentrations of carbon, Cu, Zn, Cd and Pb. Leaves from trees grown on polluted soil had larger initial Zn, Cd and dissolved organic carbon concentrations. Neither the origin of the leaves (from trees grown on non-polluted or polluted soil) nor the placement of the leaves in polluted or unpolluted soil affected the decomposition process. Total metal contents increased in leaves placed on polluted soil over time. The solubility of metals in the leaf litter decreased over time, indicating that leaves acted as a temporary pool for metals from the soil in direct contact with the leaves. The sorbed metals were strongly bound in the litter even after two years of decomposition. The strong binding and thus reduced bioavailability of the metals provides an explanation for why they had no observable effects on litter decomposition.     

Effect of passage through the intestinal tract of detritivore earthworms (Lumbricus spp.) on the number of selected Gram-negative and total bacteria

Laboratory experiments were carried out to investigate the fate of bacteria during and after passage through the intestinal tract of detritivore earthworms. Earthworms (Lumbricus spp.) were fed with cattle dung inoculated 7 days previously with one of five different Gram-negative bacteria. Bacterial concentrations were determined 2 days later in dung and soil, and in gut material from different parts of the earthworm intestinal tract. A high percentage (28–82%) of the total bacteria (epifluorescence direct counts) in the earthworm gut content was culturable. The concentration of total heterotrophic aerobic bacteria did not vary significantly among the five different bacterial additions and the non-inoculated control. In earthworm casts the number of total heterotrophs per gram dry matter (2.1×10⁹) was higher than in soil (1.7×10⁸), but lower than in the dung (1.5×10¹⁰). The test-bacteria, however, showed different survival patterns along the earthworm intestinal tract. The concentrations of Escherichia coli BJ 18 and Pseudomonas putida MM 1 and MM 11 in earthworm casts were lower than in the ingested dung, while concentrations of Enterobacter cloacae A 107 and Aeromonas hydrophila DMU 115 in dung and casts were similar. Ent. cloacae, and to aminor extent E. coli, were reduced in numbers by several orders of magnitude in the pharynx and/or crop. In the hind gut, however, the concentration of Ent. cloacae had increased to the same level as in the ingested dung, while the concentration of E. coli remained low. Our observations indicate that the bacterial flora of ingested food materials changes qualitatively and quantitatively during gut transit.     

Feeding preferences of the collembolan Onychiurus sinensis for fungi colonizing holm oak litter (Quercus rotundifolia Lam.)

Ten fungi isolated from decaying holm oak leaves (Quercus rotundifolia Lam.) have been presented to the collembolan species Onychiurus sinensis (Hexapoda). The attractiveness and selectivity of the ten fungi was investigated taken into account the effect of the substrate on which the fungus was growing (malt-agar or litter) and the effect of fungal odour. Furthermore, moulting, growth, survival and reproduction of O. sinensis in the presence of each of the ten test fungi were studied. Mucor plumbeus and Trichothecium roseum were the most preferred whatever the culture substrate and their odour was the most attractive. Two fungi (Penicillium spinulosum and the Basidiomycete S41) attracted Collembola by their odour but were not preferred as food sources. The animals could survive and reproduce on a mono-diet of several of our test fungi, but not on the Basidiomycete S41 and on Trichoderma polysporum.