Search

The mite and fungal biota associated with the mountain pine beetle (MPB) (Dendroctonus ponderosae Hopk.) may not be stable throughout an irruptive event. In congeneric beetles, variations in the frequency of their associated organisms affect population trends and similar effects may occur in MPB. We studied fungi and mite trends in a declining irruptive MPB population as it attacked three different pine hosts in the Colorado Front Range. During the study, we found two new associates including one biologically relevant mite and one beneficial blue-stain fungus. Fungi hyperphoretic on mites were also documented. This included beneficial and potentially detrimental species to the MPB. The frequency of several organisms varied between some years or pine hosts but not within male or female beetles. A large increase of Trichouropoda sp. and T. ips mites trended inversely with the declining beetle population, while a decrease in the beneficial blue-stain fungi trended similarly to the declining beetle population. We discuss the interactions and potential effects of phoretic biota in relation to (1) the MPB associates&rsquo, population trends, (2) the MPB incursions into cooler areas, and (3) the redundancy of blue-stain fungi carried by the MPB holobiont. These findings increase our knowledge of the mechanisms that influence MPB populations.

Basidiomes of polypore fungi host many insects. Yet systematic information about insect assemblages from most fungal species is lacking. We studied the insect community associated with the wood-decaying fungus Inonotus radiatus (Sowerby: Fr.) P. Karst. (Hymenochaetales). More specifically, we studied the effect of successional stage and weight of basidiomes, as well as shore exposition (north or south), on species richness and composition, as well as occurrence and abundance of the most abundant fungivores. Basidiomes were collected from riparian forests at five lakes in Sweden. Insects were reared out from the basidiomes in the laboratory. A total of 5645 adult insect individuals of 117 taxa were obtained. Among these, 2782 specimens of 36 taxa use Inonotus radiatus basidiomes as breeding habitat. Eight species of parasitic wasps were new to Sweden. The most abundant fungivore was Ennearthron cornutum (Ciidae), which is a generalist breeding in many polypore species. Based on our material and lit...

Successional dynamics in terrestrial ecosystems is important for interactions between aboveground and belowground subsystems. In this study, nematode communities in a Hailuogou Glacier Chronosequence from seven stages were investigated to determine whether changes in soil phosphorus (P) and nematode assemblages parallel those observed in aboveground communities, and whether the primary succession in this chronosequence has entered a retrogressive phase after 120 years of succession. The initial 40-year succession, including stages 2, 3 and 4, can be viewed as a build-up phase. Especially at stage 3, vegetation succession from grassland to forest accelerated the accumulation of plant litter and bioavailable P, paralleled with a sharp increase in nematode abundance. The mature phases covering stages 5, 6 and 7 displayed most balanced nematode communities, in which abundance, taxon richness, maturity index and structure index were at highest. However, the last stage 7 appeared to show some retrogressive characteristics, as suggested by the reduced bioavailability of P and a significant decrease in nematode densities, along with the disappearance of some rare genera of nematodes from higher trophic guilds, resulting in decreases in the nematode channel ratio, plant parasite index and enrichment index. Thus, the Hailuogou Glacier Chronosequence may enter its retrogressive phase during the next decade or century. A bacterial-based nematode energy channel dominated the chronosequence during the development; by contrast, a fungivore-based channel was activated at the early and late stages, because fungivores are better adapted to nutrient-poor environments. Our results demonstrated that different nematode guilds have contrasting responses to chronosequence stages, possibly due to their different responses to bottom-up and top-down controls. Furthermore, soil nematode communities could be used as sensitive bioindicators of soil health in glacial-retreat areas. (C) 2015 Elsevier Ltd. All rights reserved.

Extensive ash mortality caused by the non-native emerald ash borer alters canopy structure and creates inputs of coarse woody debris as dead and dying ash fall to the forest floor; this affects habitat heterogeneity; resource availability; and exposure to predation and parasitism. As EAB-induced (emerald ash borer-induced) disturbance progresses the native arthropod associates of these forests may be irreversibly altered through loss of habitat; changing abiotic conditions and altered trophic interactions. We documented coleopteran communities associated with EAB-disturbed forests in a one-year study to evaluate the nature of these changes. Arthropods were collected via ethanol-baited traps on five sites with varying levels of EAB-induced ash mortality from May to September; captured beetles were identified to the family level and assigned to feeding guilds (herbivore; fungivore; xylophage; saprophage; predator; or parasite). Over 11,700 Coleoptera were identified in 57 families. In spite of their abundance; herbivores comprised a relatively small portion of coleopteran family richness (8 of 57 families). Conversely, coleopteran fungivore richness was high (23 families), and fungivore abundance was low. Herbivores and fungivores were more abundant at sites where ash decline was most evident. The predatory Trogossitidae and Cleridae were positively correlated with ash decline, suggesting a positive numerical response to the increased prey base associated with EAB invasion. Ash forests are changing, and a deeper understanding of arthropod community responses will facilitate restoration.

Species with close associations to a specific host species, such as parasites and phytophages, make immense contributions to biodiversity. Hence, factors determining the variation in species richness among hosts are a main focus of ecological research. Investigations of determining factors of fungivorous species among host species are still scarce. Based on ecological patterns of parasites and phytophages, we hypothesized that the species richness of tree-fungus beetles of the family Ciidae (Coleoptera) would increase with increasing basidiome size, niche diversity of the growth form, durability, increasing abundance and decreasing phylogenetic isolation of the host fungus. Our generalized least-squares model, controlled by host phylogeny, revealed that Ciidae species richness increases with host abundance, but decreases with host phylogenetic isolation. In contrast with our prediction, Ciidae species richness was higher in annual basidiomes than in perennials. Pileate basidiomes revealed higher species richness than resupinate and stipitate basidiomes, which may be interpreted as being a result of their higher host niche diversity. The importance of host abundance, measured on the landscape scale, corroborates that fungivore species richness among macrofungal hosts is determined by factors similar to those that determine parasite and phytophage species richness among their hosts. © 2015 The Linnean Society of London, Biological Journal of the Linnean Society, 2015, 114, 699–708.

Protogamasellus mica was extracted from a sugarcane field in Australia and cultured on bacterial-feeding nematodes. Studies with various nematodes in laboratory arenas showed that one mite and its progeny reduced nematode numbers by between 26 and 50 nematodes/day. A bacterivore (Mesorhabditis sp.), a fungivore (Aphelenchus avenae), and two plant parasites (root-knot nematode, Meloidogyne javanica and root-lesion nematode, Pratylenchus zeae) were all reduced at much the same rate despite the fact that the nematodes are quite different in size and motility and belong to different trophic groups. When sugarcane was grown in the greenhouse for 8 wk, stunt nematode (Tylenchorhynchus annulatus), a plant parasite that feeds ectoparasitically on roots, was almost eliminated from pots inoculated with the mite, and numbers of microbivores and root-lesion nematode were markedly reduced. Huge reductions in nematode populations were also observed when mites were added to microcosms containing small quantities of defaunated soil. These results show that P. mica multiplies rapidly when nematodes are available as a food source and has the capacity to play a role in regulating populations of both plant-parasitic and free-living nematodes. Future research should focus on understanding the crop and soil management practices required to enable this mite and other predatory species to thrive.

A mysterious female phorid fly, known for many years to be associated with fungal sporophores ("mushrooms") is identified as Megaselia marquezi Hartop et al. 2015. Male and female flies were collected emerging from the fungus Psathyrella candolleana (Fr.) Maire, and females were observed swarming over the sporophores.

We studied the role of nematode predation in the functioning of detrital food webs assembled in microcosms. The microcosms contained defaunated humus and litter materials, a diverse microbial community with bacteria, fungi and protozoa, and a birch (Betula pendula) seedling infected with mycorrhizal fungi. Different levels of top-down control upon microbivorous nematodes were set up by assembling food webs either without predators, or in combinations with a specialist and a non-specialist predatory mite (Mesostigmata). The nematode community was composed of either (1) three species of bacterivorous, or (2) three species of fungivorous nematodes or (3) both groups together. After two growing periods for the birch (38 weeks), the microcosms were destructively sampled for animal and microbial biomasses, concentration of mineral N in the soil, plant biomass and plant N concentration. The specialist predator reduced biomasses of both bacterial- and fungal-feeding nematodes by more than 50%, whereas the non-specialist predator weakly increased the biomass of fungivorous nematodes. Thus, under high predation pressure, the biomass of microbivores changed as predicted by trophic dynamic models assuming strong top-down control and uniformly behaving trophic levels. Despite this, microbial biomass was unaffected by the predators. However, microbial respiration increased slightly in the presence of predators. Assuming that microbial respiration correlates with microbial productivity, the increase in microbial respiration indicates a cascading productivity regulation. The composition of the microbivore community had only a minor effect on the outcome of the top-down control on microbes. The >50% reduction in nematode biomass and respiration coincided with

Previous theoretical and empirical evidence suggests that species composition within trophic levels may profoundly affect the response of trophic-level biomasses to enhanced basal resources. To test whether species composition of microbivorous nematodes has such an effect in microbial-based soil food webs, I created three microcosm food webs, consisting of bacteria, fungi, bacterial-feeding nematodes (Acrobeloides tricornus, Caenorhabditis elegans), fungal-feeding nematodes (Aphelenchus avenae, Aphelenchoides sp.) and a predatory nematode (Prionchulus punctatus). The food webs differed in species composition at the second trophic level: food web A included A. tricornus and Aph. avenae, food web B included C. elegans and Aphelenchoides sp., and food web AB included all four species. I increased basal resources by adding glucose to half of the replicates of each food web, and sampled microcosms destructively four times during a 22-week experiment to estimate the biomass of organisms at each trophic level. Microbivore species composition significantly affected bacterivore and fungivore biomass but not bacterial, fungal or predator biomass. Greatest bacterivore and fungivore biomass was found in food web A, intermediate biomass in food web AB, and smallest biomass in food web B. Basal resource addition increased the biomass of microbes and microbivores but did not affect predator biomass. Importantly, microbivore species composition did not significantly modify the effect of additional resources on trophic-level biomasses. The presence of a competitor reduced the biomass of A. tricornus and Aph. avenae, in that the biomass of these species was less in food web AB than in food web A, whereas the biomass of C. elegans and Aphelenchoides sp. was not affected by their potential competitors. The biomass of Aph. avenae increased with additional resources in the absence of the competitor only, while the biomass of A. tricornus and Aphelenchoides sp. increased also in the presence of their competitors. The results imply that microbivore species composition may determine the second-level biomass in simple microbe-nematode food webs, but may not significantly affect biomass at other levels or modify the response of trophic-level biomasses to enhanced basal resources. The study also shows that even if the role of predation in a food web is diminished, the positive response of organisms to increased resource availability may still be hindered by competition.

We analysed the soil nematode community within three different montados (agricultural, pastoral and forestry uses), focusing on temporal variation. Nematodes were classified into trophic groups (bacterivores, fungivores, omnivores, predators and plant-parasitic nematodes (PPN)) and we calculated the maturity index for free-living taxa (MI), maturity index for plant-parasitic taxa (PPI) and the nematode channel ratio (NCR). Temporal variations were most evident during winter when there was a rise in the abundance of the five functional groups. Concordantly, there was a simultaneous increase of soil moisture and organic matter, due to litter decomposition. Fungivore abundance was highest in the forest and the temporal occurrence and abundance of many PPN genera was largely determined by land use. Land management was responsible for differences in plant community structure and composition, thus plant diversity increased from the agricultural to the forestry use. Because the montado shows great temporal variability in vegetation structure our results of MI, PPI and PPI/MI ratio explain the significant changes in the nutritional status over time, with the highest values recorded in the spring. NCR is a good indicator of energy efficiency in the soil decomposition process. Its lowest values were attained in the forest, where the slow-growing plant species favoured a lower activity of the bacterial energy channel and a prevalence of the fungal-based decomposition energy channel. Nematode composition reflected plant succession, changes in decomposition in the soil food web and temporal variations in the structure of soil.

An enormous variety of volatile substances are released in distinctive blends by fungal substrates that should be recognisable for fungivores. Certain compounds dominate in most of the fungal species. Fungal oxylipins as the eight-carbon volatiles are the most prominent. This raises the question whether such are specific enough to qualify as appropriate host cues for a fungivore. We could demonstrate differentiated responses of the fungivorous beetle Bolitophagus reticulatus to eight-carbon volatiles: Nine eight-carbon volatiles were identified with GC–MS from its host fungus Fomes fomentarius. 1-Octen-3-ol, 3-octanone and 3-octanol induced contrasting behaviour of beetles in olfactometer bioassays. Electroantennographic experiments investigating the beetle olfactory sense revealed distinguishable antennal responses. Moreover, their individual release from F. fomentarius fruiting bodies changes not only considerably, but also independently over successive stages of beetle colonisation. Concentrations of attractive and repellent eight-carbon volatiles correlate to frequency of beetles in the field and further substantiate their relevance as host cues. Our results show that a specialist fungivore is able to differentiate the most common eight-carbon volatiles of fungi to assess host quality. Key roles and marked similarities of fungal to plant oxylipins suggest a comparable importance of eight-carbon volatiles to fungivores as green leaf volatiles have to herbivores.

Prescribed fire produced a landscape with two types of severely burned patches: charred shrub patches and charred patches with tree trunks at the center. Soil nematodes were more abundant in burned and unburned juniper (Juniperus monosperma) tree patches than in yucca-shrub patches. There were no differences in nematode abundance between burned and unburned patches during the late spring and summer samples. Nematode abundance was significantly (p i.e., by loss of tree canopies, litter accumulation, and shrub foliage, which affects soil temperatures and water redistribution.

We sampled the bark beetle Ips pini (Say) in Wisconsin red pine stands to describe its phoretic mite community. Nearly 78% of adult beetles carried phoretic mites, with an average of 12.78 ± 0.76 individuals and 1.69 ± 0.05 species per beetle. Phoretic mites from flying beetles represented over 13 families. Five species of mites showed relatively close associations, being present on at least 10% of adult beetles. The most common mite species included one from each of the major guilds on bark beetles, the scavenger/fungivore Histiostoma spp. (41.5% of beetles), the egg predator Iponemus confusus (Lindquist) (41.1% of beetles) and the nematode predator Dendrobebps quadrisetus (Berlese) (32.8% of beetles). Beetles in northern Wisconsin had more diverse phoretic mite communities than those in central or southern Wisconsin. Beetles collected late in the season (July-August) carried more individuals and species of mites than those collected early in the season (May-June). The method we used to collect live bark beetles may be useful for other studies requiring fine-scale quantification of symbionts, such as bacteria, fungi, and nematodes.

A total of 12 soils collected from different agricultural fields, having different backgrounds of organic input, were evaluated for their suppressive potential against Meloidogyne incognita. Second-stage juveniles (J2) of M. incognita were inoculated into the soils and their survival was evaluated. The number of M. incognita J2 5 days after inoculation differed depending on soil and was significantly lower in two soils, suggesting higher suppressiveness against M. incognita in these soils. This was confirmed by an experiment using tomato as a test plant, in which the gall formation was significantly lower in the two soils than in other soils. To estimate the contribution of below-ground biota to the suppressiveness, numbers of nematodes (predator, omnivore, bacterivore and fungivore) and other soil fauna such as tardigrades and rotifers, were counted. Some soil chemical and biological properties were also measured. Results from multiple linear regression analysis suggested that the number of rotifers, microbial activity, soil pH and total C may be involved in the suppression. The relationship between the suppressiveness and soil chemical and biological parameters is discussed.

1. Aggregative behaviour in fungivorous soil arthropods is widespread; its adaptive value, however, is largely unknown. In this study, the spatial foraging behaviour of a collembolan, Folsomia candida, and the fitness consequences of feeding at different densities on the filamentous fungus Aspergillus nidulans were investigated. The effect of two fungal strains were compared; a wild-type (wt) and a transgenic strain that lacks the ability to express the global secondary metabolite regulator LaeA (ΔlaeA). 2. In laboratory foraging tests, F. candida exhibited aggregated distributions of individuals across four distinct fungal colonies that were arranged in short distances from each other. By quantifying the extent of the feeding damage at each single colony, a more evenly distributed feeding activity was found among wt colonies than among chemical-deficient colonies. 3. In a fitness experiment, where collembolans at different densities were restricted to feed on single A. nidulans colonies, mean growth rate of F. candida was positively related to density on the wt A. nidulans strain, but negatively related to density on the chemical-deficient strain. 4. Depending on the fungus' ability to express secondary chemicals and availability of fungal food sources, F. candida may employ different foraging strategies: (i) avoidance of prolonged feeding on single colonies in a rich habitat (travel costs low), and (ii) intensified group feeding on single colonies in a resource-limited habitat (travel costs high). It was hypothesised that flexibility in fungivore foraging behaviour (clumping vs. spreading feeding activity) is adaptive because it allows avoidance/overcoming induced fungal chemical defence.

The objective of this study was to differentiate sites influenced by long-term application of synthetic fertilizers, herbicides and tillage, using the percentages of nematode trophic groups and ecological indices on fruit orchards. The experiments were conducted in Upper Rio Negro Valley, on medium texture soils. Seven sampling sites were established. Soil samples were collected in October, for two consecutive years. Main component analyses were performed. The distribution of the sites, according to the percentage of trophic groups (bacterivores, fungivores, plant feeders and omnivores-predators) and community indices of nematodes (MI, PPI, EI and SI) showed a different pattern of arrangement. Each long-term soil management supported different nematode assemblages. The plant-parasitic nematodes were the most abundant group in sites fertilized with nitrogen and under application of herbicide for at least ten years. The percentage of fungivore nematodes was higher in soils subjected to application of herbicides, no fertilizers and no tilling. Soils with a similar assemblage of nematodes, expressed in percentages of trophic group, did not necessarily presented a similar functional condition of the throphic web. The interpretation of the studied parameters can provide useful information about the nutritional status and ecological health of the soil in fruit orchards.

Invasive Alternanthera philoxeroides (alligator weed), when controlled by biocontrol agent Agasicles hygrophila, is known to differ from native vegetation in its decomposition dynamics. This study investigated whether this difference would have indirect effects for fungal-feeding Coleoptera. The study tested the hypothesis that fungivores would be more abundant and species rich on A. philoxeroides than on native vegetation. The study also tested the hypothesis that fungivores would be more affected than other functional groups. The study was conducted in a northern New Zealand lake. Litterbags were placed beneath A. philoxeroides and two native sedge species (Schoenoplectus tabernaemontani and Isolepis prolifer). Coleoptera communities were examined from the litterbags. Fungivorous Coleoptera were more abundant and species rich beneath A.philoxeroides than beneath either sedge species. No other functional groups differed between cover types. Fungivorous Coleoptera also comprised a greater proportion of total Coleoptera catch from litterbags beneath A.philoxeroides cover than from beneath native sedge cover. Four of the six fungivorous Coleoptera species collected in the study were present beneath A.philoxeroides cover. Of these, the two most abundant species (on native, one exotic) were both from the family Corylophidae. Alternanthera philoxeroides invasion is thus associated with altered Coleoptera communities in this ecosystem.

Soil nematode communities were investigated in the Changbai Mountain in Broad-leaved Korean Pine forest, Korean Pine and spruce-fix mixed forest, Dark Coniferous forest, Erman’s birch forest and Alpine tundra along different altitude gradients from 762 m to 2 200 m a.s.l. Soil animal samples were collected from the litter layer and the soil depth of 0–5 cm, 5–10 cm and 10–20 cm at each site in the spring of 2001 and 2002. In total 27 nematode families and 60 genera were observed. The dominant genera were Plectus Bastian and Tylenchus Bastian and most of them live in litter layer. The total number of soil nematode was significantly correlated with soil moisture (r=0.357; p

Trees have a key role in determining the composition of soil biota via both above and belowground resource-based mechanisms, and by altering abiotic conditions. We conducted an outdoor mesocosm experiment to investigate the relative impact of above and belowground tree inputs on soil nematode trophic composition, and examine whether tree-driven impacts differed between contrasting species (birch and pine). For both species, we created a factorial design of litter addition and root presence treatments. The litter addition treatment was equivalent to natural levels of litterfall; tree saplings were planted in mesocosms for the root presence treatment and an unplanted control treatment was established that had no litter or root inputs. Litter addition had a limited impact on soil nematode community composition: it primarily decreased omnivore and predatory nematode abundance in birch but had few other effects on the nematode community. By contrast, root presence markedly altered nematode community composition through changes in a range of trophic groups. For both birch and pine, there were significant increases in total, fungivore and predatory nematode abundance in root presence treatments, and furthermore, total and fungivore abundances were positively related to root biomass. Root presence of these contrasting tree species also had a distinctive impact on some specific nematode trophic groups; pine roots promoted bacterivore abundance while birch roots promoted root-hair feeding nematode abundance. These findings suggest strong bottom-up effects of belowground tree inputs, and indicate that particular components of the nematode community may be affected differently by resource quantity and quality. Consequently, we suggest that, in the short-term, belowground rather than aboveground tree inputs have a strong impact on soil food web structure and complexity.

Since its accidental introduction to south-east England during the nineteenth century, the invasive Australasian fungivore, Cis bilamellatus, has spread across England, Wales and Southern Scotland. Recently it has been recorded from Ireland, the Channel Islands and north-west France. On mainland Britain, an establishment phase spanning an estimated maximum of 45 years was followed by biphasic range expansion comprising a slow start of 1.6 km year−1 between 1910 and 1930, followed by 40 years of approximately linear spread of 13 km year−1. Northwards expansion now appears to be limited by sub-zero winter temperatures and is no longer apparent. Comparison with historic records of native ciids shows that this range expansion is genuine, rather than an artefact of recording effort or bias. It has no doubt been facilitated by C. bilamellatus’ ability to exploit a wide range of sometimes under-used fungal resources, by its favourable rate of increase, by its tolerance of both wet and dry conditions, and by a low rate of parasitoid attack. Although there is the potential for direct and indirect interaction between C. bilamellatus, native ciids and their shared parasitoids, the current ecological impact of C. bilamellatus appears to be low. It seems likely that C. bilamellatus will spread through Europe, limited primarily by resource availability and low winter temperatures.

Orchid mycorrhiza probably affects about 25 000 plant species and thus roughly one tenth of all higher plants. Histologically, this symbiosis resembles other kinds of endomycorrhiza, the fungal hyphae growing within living plant cells. Considerable evidence, however, suggests that it is not a two-way exchange relationship and thus not potentially mutualistic, such as the wide-spread endomycorrhiza between plants and Glomalean fungi, known as arbuscular mycorrhiza. During the achlorophyllous seedling stage orchids are obligately dependent on the fungi; some species remain so through life, while others establish photosynthesis but to varying degrees remain facultatively dependent of / responsive to fungal infection as adults. None of the fungi involved are so far known to depend on the symbiosis with orchids. Transfer of organic carbon compounds from hyphae to the orchid has been demonstrated repeatedly, but it is not clear to what extent this takes place during a biotrophic phase while the intracellular hyphae remain intact, or during the subsequent extensive degradation of the hyphal coils. The advantage of viewing orchid mycorrhiza basically as a unilateral mycophagous relationship, in spite of hypothetical beneficial spin-offs to the mycobiont, is that it provides a conceptual framework similar to that of other parasitic or fungivore relationships; mechanisms known in such relationships could be searched for in future studies of the orchid-fungus symbiosis. These could include mechanisms for recognition, attraction and selection of fungi, physiological regulation of internal hyphal growth, breakdown, and material transfer, nutritional consequences of the plant's preference(s) and trophic changes, fungal avoidance mechanisms, and consequences at population and ecosystem levels. A whole range of possible life strategies becomes apparent that could support divergent evolution and lead to the proliferation of species that has indeed occurred in the orchid family. We outline some of the possible physiological mechanisms and ecological implications of this approach.

The present study was directed towards the habitat of various mite species as predators, fungivores or as parasitesassociated with insects inhabiting grains and stored products. Samples were collected monthly from maize, wheat flour,broad bean, wheat and rough rice in four governorates, Kafr El-Sheikh, Dakahleya, Gharbeya and Menoufeya duringthe period between March 2003 and February 2004. The results revealed that: 1) The mite survey revealed theoccurrence of 13 predatory species belonging to one family of the suborder Gamasida, and 6 families of the suborderActinedida. Also 7 species belong to 4 families of the suborder Acaridida, were recorded as scavengers or fungivores.2) The most abundant predaceous mites were: Blattisocius keegani Fox followed by Cheyletus malaccensis Oudemans,then Blattisocius tarsalis (Berlese). 3) The most abundant fungivore mites were: Tyrophagus putrescentiae (Shranck),Rhizoglyphus robini Claparede, and Acarus siro Linnaeus. 4) The most infested stored grains with mites was maizefollowed by wheat, rough rice, broad bean seeds then wheat flour. 5) The major insect pests of stored grains and seedsand associated mites were listed herein.

Summary A microcosm technique was used to determine the ecotoxicity of the chemical warfare agent HD (mustard) to the indigenous soil microinvertebrate communities. HD was thoroughly incorporated into Sassafras sandy loam (SSL) soil (4.9% OM) and an oak-beech forest silt loam soil (FS, 16% OM) at nominal HD concentrations ranging from 6 to 1076 mg kg−1. After a 7-day incubation period, microarthropods were extracted from soils using a high-gradient extractor and sorted to Acari suborders Prostigmata, Mesostigmata, and Oribatida, and the insect order Collembola. Nematodes were extracted using Baermann funnels and were sorted into bacterivore, herbivore, fungivore and omnivore/predator trophic groups. Microarthropods were more sensitive to HD in both soil types compared with nematodes. The EC50 values for total numbers of microarthropods in SSL and FS were similar (65 and 71 mg kg−1, respectively). The EC50 values for total numbers of nematodes were 130 and 235 mg kg−1, respectively. Toxicity of HD to nematodes was significantly greater in SSL soil compared to FS, based on 95% confidence intervals. Results show that community-level assessment of chemical toxicity in soil using a microcosm assay is sufficiently robust and can provide the means for validating the ecotoxicity data from standardized laboratory single-species toxicity tests.

The percentage compositions of soil herbivorous, bacterivorous and fungivorous nematodes in forests, grasslands and scrubs in Romania was analysed. Percentages of nematode abundance, biomass and metabolic footprint methods were used to evaluate the patterns and relative size of herbivory, bacterial- and fungal-mediated channels in organic and mineral soil horizons. Patterns and magnitudes of herbivore, bacterivore and fungivore energy pathways differed for a given ecosystem type and soil depth according to the method used. The relevance of herbivore energy channel increased with soil depth due to higher contribution of root-feeders. Ectoparasites, sedentary parasites and epidermal cell and root hair feeders were the most important contributors to the total biomass and metabolic footprints of herbivores. Metabolic footprint method revealed the general dominance of bacterial-based energy channel in all five types of ecosystems. The influence of altitude and climatic factors on percentages of abundance, biomass and metabolic footprints of herbivores, bacterivores and fungivores decreased with soil depth, whereas the influence of humus content, cation-exchange capacity and base saturation increased. Vegetation, altitude, climate and soil physico-chemical characteristics are important factors that influenced the abundance, biomass and metabolic footprints of herbivores, bacterivores and fungivores.

Recent research shows that continuous overgrazing not only causes grassland biodiversity to decline, but also causes light fungal disease. Achnatherum inebrians is susceptible to fungal diseases and increases in prevalence during over grazing due its toxicity to livestock. This study aimed to examine the effects of A. inebrians on biological control organisms and levels of plant diseases in overgrazed grasslands in northwestern China. The results showed that A. inebrians plants were seriously infected by fungal diseases and that this led to a high incidence of the mycoparasitic species Ampelomyces quisqualis and Sphaerellopsis filum. In addition, the fungivore, Aleocharinae, was found only in the soil growing A. inebrians rather than in the overgrazed area without A. inebrians. Overall, in an overgrazed grassland fenced for one year, disease levels in blocks without A. inebrians were significantly higher than those in blocks with A. inebrians. Our findings indicated that the disease susceptible, toxic A. inebrians can help control plant disease levels in overgrazed grasslands.

Members of the family Mycetophilidae (Diptera) have life cycles that are typically associated with fungus. Their biology is relatively well known in the Palaearctic, though other regions are poorly known, and there are no associations recorded between mycetophilid immatures and fungi in the Neotropical region. Here we report the first association between a mycetophilid—Neoempheria puncticoxa Edwards—and fungi in this region. Immatures of N. puncticoxa were collected on fungi and some were reared in the laboratory until adult emergence. The immature stages and adult of N. puncticoxa are described and re-described respectively, and high resolution images and illustrations of the habitus, wings, thorax, male and female terminalia, immatures, and in situ specimens are given. We report the first association between Mycetophilidae and fungi in the Neotropical region.

Theory predicts that spatial structure can mediate interactions that affect species diversity in a patchy environment. A rarely considered effect of spatial structure on biodiversity is the interplay of spatial habitat arrangement with species interactions at multiple spatial scales. We investigated how spatial habitat arrangement and predation mediate the assembly of the larval communities of fungivorous insects breeding in the oyster mushroom, Pleurotus ostreatus (Jacq. ex Fr.) P.Kumm in a North American woodland. In a two-way factorial design, we varied the spatial arrangement of mushroom clumps (‘clustered', ‘patchy', and ‘uniform'; 3 levels) crossed with predator exclusion (access allowed or not; 2 levels) to study their joint effects on patterns of α, β and γ diversity of the fungivorous insect communities. Partitioning diversity into these three components suggested that neither spatial nor predation treatments significantly affected α, β and γ diversity. We found that an intermediate inter-clump distance (i.e., the ‘patchy' treatment) increased spatial autocorrelation in insect community composition within experimental blocks, particularly in the mushrooms to which predators had access. The spatial structuring in β diversity indicates that the arrangement of mushroom clumps can structure β diversity of fungivorous larval communities through direct effects on the species themselves (e.g., increased aggregation and habitat choice of ovipositing females of fungivorous insects), as well as effects mediated through the presence and behavior of predators (e.g., spatially structured selective foraging by predators acting as a filter on which species were in the clumps). The naturally patchy nature of mushroom fruiting may transform the spatial pattern of β diversity by altering the behavior of ovipositing females, or by weakening the negative effect of larval competition.

Patterns of fungal spore dispersal affect gene flow, population structure and fungal community structure. Many Basidiomycota produce resupinate (crust-like) basidiocarps buried in the soil. Although spores are actively discharged, they often do not appear to be well positioned for aerial dispersal. We investigated the potential spore dispersal mechanisms of one exemplar of this growth form, Tomentella sublilacina. It is a widespread ectomycorrhizal fungus that sporulates in the soil organic horizon, can establish from the spore bank shortly after disturbance, but also can be a dominant species in mature forest stands. We investigated whether its spores could be dispersed via spore-based food webs. We examined external surfaces, gut contents and feces from arthropod fungivores (mites, springtails, millipedes, beetles, fly larvae) and arthropod and vertebrate predators (centipedes, salamanders) from on and around T. sublilacina sporocarps. Spore densities were high in the guts of many individuals from all fungivore groups. Centipede gut contents, centipede feces and salamander feces contained undigested invertebrate exoskeletons and many apparently intact spores. DAPI staining of spores from feces of fungivores indicated that 7-73% of spores contained intact nuclei, whereas spores from predators had lower percentages of intact nuclei. The spiny spores often were lodged on invertebrate exoskeletons. To test the viability of spores that had passed through invertebrate guts we used fecal droppings of the millipede Harpaphe haydeniana to successfully inoculate seedlings of Pinus muricata (Bishop pine). These results indicate the potential for T. sublilacina spore dispersal via invertebrates and their predators in soil food webs and might help to explain the widespread distribution of this species. It is likely that this is a general mechanism of dispersal for fungi producing resupinate sporocarps, indicating a need to develop a fuller understanding of the linkages of soil food webs and spore dispersal.

Epichloe spp. (Ascomycetes: Clavicipitaceae) are endophytic fungii of Pooid grasses that cause choke disease, the suppression of seed production. They also host Botanophila spp. (Diptera: Anthomyiidae), the larvae of which feed on the fungus. Studies on Epichloe elymi on wild grasses indicate that the flies transfer spermatia between Epichloe mating types, thereby affecting cross-fertilization, suggesting that the fungus-fly interaction reflects obligatory mutualism. Epichloe typhina, inadvertently introduced into western USA, was first detected in cultivated Dactylis glomerata L. fields in 1996. It spread rapidly, raising concerns about impacts on seed production. The present study was conducted to address questions pertaining to the occurrence and nature of the fungus-fly interaction in the new habitat of E. typhina. The first report of an endemic Botanophila species associated with E. typhina in Oregon is presented here. Surveys of D. glomerata fields indicated no correlation between fly abundance and fungal fertilization. In one field, no fly eggs or larvae were detected, but fertilized stromata were universally present. The fly was established in the remaining 12 fields surveyed, but while the number of stromata with fly larvae ranged from 6 to 98%, stromata development was uniform. Up to 10 larvae were present on a stroma, and these consumed >90% of the perithecia. Comparisons of pupal weights indicated that the fungal resource was not limiting, even at high larval densities. An exclusion study in a D. glomerata field also indicated that E. typhina fertilization occurred without the fly. In Oregon, the fly clearly benefits from the association with the fungus, but there is no evidence of benefit to the fungus. Thus if obligatory mutualism in the fungus-fly relationship described from the midwestern USA is the norm, our studies suggest a shift in the interaction to one of simple foraging on the fungus by fly larvae.

We tested the hypotheses that management of the soil food web in the fall would enhance grazing on bacteria and fungi by microbivorous nematodes in the spring, consequently increasing N availability in cover-crop driven organic and low-input farming systems. The food web was manipulated by irrigating the dry soil of late summer and/or providing carbon sources. By creating conditions conducive for biological activity, we increased the abundance of bacterivore and fungivore nematodes in the fall and the following spring. Greater biological activity in the soil enhanced concentrations of mineral N available to the subsequent summer tomato crop. Mineral N concentration in the spring was associated with abundance of bacterivore nematodes, and with the corresponding Enrichment Index (EI) provided by nematode community analysis. Because environmental conditions that favour increase of bacterivore nematodes probably also favour other microbial grazers, including protozoa, the abundance of bacterivore nematodes may be an indicator of overall grazing activity and N mineralisation rates from soil fauna. Decomposition pathways in the spring, inferred from nematode bioindicators, were dominated by bacteria in plots that had been irrigated the previous fall while fungi were more prevalent in those that had not. The responses of omnivore and predator nematodes to our treatments were not consistent and there was no evidence that regulation of opportunist species by predators would be enhanced by the management practices imposed.

Soil microplots were amended with organic materials of varying nature and complexity but providing similar amounts of carbon. Materials were either placed on the soil surface or incorporated. Unamended and mineral fertilizer control plots were established. Plots were maintained vegetation-free so that the food web activity was fueled by resident soil organic matter and the input material. Enrichment-opportunist bacterivore nematodes increased rapidly in response to low C/N plant materials and, to a lesser extent, to more complex materials. General-opportunist bacterivores increased in all plots, but at a slower rate. Fungivore nematodes also increased gradually in all plots but most rapidly in those amended with higher C/N and more complex materials. Indices derived from nematode faunal analysis suggested a constant rate of succession from enrichment-opportunist to general-opportunist bacterivore guilds across all treatments, probably mediated by bacterial abundance and differences in life course characteristics of the respective taxa. The rate of succession from bacterivore to fungivore nematodes was greatest in plots receiving high C/N materials. Succession to fungivory, presumably indicating a shift from bacterial to fungal decomposition channels, was slowest in those plots with a high level of organismal metabolic activity, as measured by soil respiration. The cumulative amounts of N mineralized in the plots were directly related to the enrichment index (EI), based on the abundance of opportunistic bacterial- and fungal-feeding nematodes. The amounts of mineralized N were inversely related to the slope of the channel index (CI), that is, the rate at which decomposition changed from bacterial to fungal. Maintenance of adequate soil fertility in systems driven by organic input may require maintenance of food web structure and function as indicated by high levels of enrichment-opportunist bacterivore nematodes. That will require frequent supply of labile organic sources. Allowing food web succession to guilds that indicate lower mineralization potential will result in lower levels of soil fertility.

Summary We studied the effect of the earthworm, Eisenia andrei, on the nematode community and on the microbial activity during the vermicomposting of two organic wastes, cow manure and sewage sludge. Fresh cow manure and sewage sludge was placed in five replicated boxes with and without earthworms for a period of 16 weeks. Samples were collected periodically and nematodes were extracted in Baermann funnels, counted and separated into different trophic groups. Samples were also analyzed for microbial respiration and microbial biomass nitrogen. Nematode communities were dominated by bacterivores, and their abundance was dramatically affected by earthworm activity. In both substrates, numbers of nematodes decreased in the presence of earthworms. Fungivore nematodes were observed after 6 weeks in the cow manure and in contrast to bacterial feeders, their number continuously increased in the treatment without earthworms but remained low in the presence of the earthworms. We did not detect a significant earthworm effect on microbial respiration but they significantly increased microbial biomass nitrogen in sewage sludge. Our results indicate that earthworms have a strong influence on nematode densities and nematode trophic structure, and that further investigations are necessary to determine the mechanisms of this influence.

Animal grazing is a pervasive ecological factor threatening fungal fitness. This review summarizes the different approaches that have been used to test whether secondary metabolites serve as anti-fungivore defense agents. Assuming that secondary metabolites at least in part have evolved to mediate resistance against fungivores, this review evaluates the pros and cons of (1) using long-standing toxicity assays, (2) considering natural variation in fungal secondary metabolite formation, and (3) experiments with transgenic mutant fungi. Connecting inducible changes in fungal, molecular, genetic, biochemical, and morphological properties with fungivore behavioral and fitness assays is a new approach to investigate the functional relationship between secondary metabolite regulation and resistance against fungivores. Strengthening this dynamic view on fungus–fungivore interactions will certainly pave the way for a deeper understanding of how known (and still unknown) regulatory mechanisms act in concert with the biosynthesis of anti-fungivore compounds and the extent to which both constitutive and inducible variations in fungal chemical diversity represent an adaptation to animal grazing.

The drosophilid fauna in Australia offers an important study system for evolutionary studies. Larval hosts are unknown for most species, however, and this imposes serious limits to understanding their ecological context. The present paper reports the first systematic, large-scale field survey of potential larval hosts to be conducted, in order to obtain an overview of the host utilisation patterns of Australian drosophilids. Potential hosts (mostly fruit and fungi) were collected from different vegetation types in northern and eastern Australia. Host data were obtained for 81 drosophilid species from 17 genera (or 28% of the known Fauna). Most genera were restricted to either fruit or fungi, although Scaptodrosophila spp. and Drosophila spp. were recorded from fruit, fungi, flowers and compost, and Drosophila spp. also emerged from the parasitic plant Balanophora fungosa. There was no evidence that use of either fruit or fungi was correlated to host phylogeny. Drosophilids emerged from hosts collected from all sampled vegetation types (rainforest, open forest, heath and domestic environments). Vegetation type influenced drosophilid diversity, both by affecting host availability and because some drosophilid species apparently restricted their search for hosts to particular vegetation types.

Summary 1. This paper describes the structure of the insect communities inhabiting two old-growth forest specialist bracket fungi, Amylocystis lapponica and Fomitopsis rosea. To study the consequences of old-growth forest fragmentation on community structure, non-fragmented and fragmented forest areas in eastern and southern Finland were compared. 2. Both fungal species are inhabited by more than 50 insect species. The most abundant species in the A. lapponica community is a melandryid beetle Hallomenus sp., and in the F. rosea community a tineid moth Agnathosia mendicella. The occurrence of several nationally or globally rare species underscores the importance of specific insect microhabitats, such as the specialist fungi A. lapponica and F. rosea, for the persistence of specialised insects in old-growth forests. 3. The species composition in both fungal species differs greatly from each other. The food webs are characterised by one numerically dominant host-specific primary fungivore, which implies that fungivorous species inhabiting bracket fungi may be more specialised on a particular host than is generally thought. 4. The community structure was the same in the highly fragmented and in the non-fragmented study areas, probably because fragmentation has occurred relatively recently.

Several species of common fungi were assessed as food for fungivorous astigmatid mites. Hypocrea nigricans, Botrytis cinerea and Flammulina velutipes were generally good food sources for most mites examined. Fungal mycelia growing on PDA (potato dextrose agar) medium were not only nutritionally adequate but the system also maintained high humidity through the water-based agar medium. Among acarid mites, most species of Rhizoglyphinae could be reared easily with the method. Although filter-feeding histiostomatid mites do not feed directly on hyphae, some species were successfully maintained with the same method through multiple generations. Presumably, these mites obtained sufficient nutrition from the agar medium and fungal metabolites leaching into it. Most species ultimately produced dispersing heteromorphic deutonymphs on these media. Individual mites were also maintained in isolation within glass rings on fungal colonies. Using this technique, we were able to compare developmental periods, fecundity and survival periods of mites reared under different conditions.

In the summer in central Japan, the pleasing fungus beetle Episcapha fortunii Crotch 1873 was observed eating the mucus of the slug Meghimatium fruhstorferi (Collinge 1901). In addition, the darkling beetle Platydema subfascia (Walker 1858) and the false darkling beetle Synstrophus macrophthalmus (Reitter 1887) fed on Corticiaceae fungus that was soaked with slug mucus. The beetles might use slug mucus as a source of water or nutrients during dry, hot weather. These fungus-feeding beetles are considered commensals of the slug.

To study the effects of omnivory on the structure and function of soil food webs and on the control of trophic-level biomasses in soil, two food webs were established in microcosms. The first one contained fungi, bacteria, a fungivorous nematode (Aphelenchoides saprophilus) and a bacterivorous nematode (Caenorhabditis elegans), and the second one fungi, bacteria, the fungivore and an omnivorous nematode (Mesodiplogaster sp.) feeding on both bacteria and the fungivore. Half of the replicates of each food web received additional glucose. The microcosms were sampled destructively at 5, 9, 13 and 19 weeks to estimate the biomass of microbes and nematodes and the soil NH4+-N concentration. The evolution of CO2 was measured to assess microbial respiration. Microbial respiration was increased and soil NH4+-N concentration decreased by the addition of glucose, whereas neither was affected by the food-web structure. Supplementary energy increased the biomass of fungi and the fungivore, but decreased the biomass of bacteria, the bacterivore and the omnivore. The omnivore achieved greater biomass than the bacterivore and reduced the bacterial biomass less than the bacterivore. The biomass of the fungivore was smaller in the presence of the omnivore than in the presence of the bacterivore at three sampling occasions. Fungal biomass was not affected by food-web structure. The results show that the effects of the omnivore were restricted to its resources, whereas more remote organisms and soil processes were not substantially influenced. The results also indicate that the presence of an omnivore does not necessarily alter the control of populations as compared with a food web containing distinct trophic levels, and that the fungal and bacterial channels may respond differently to changes in energy supply.

The authors used a refined microcosm technique to investigate the toxicity of copper, cadmium, malathion, and the polychlorinated biphenyl, to trophic groups of soil nematodes and to the microarthropod community. Comparisons of changes in nematode abundance in control soils through time indicated that day 7 was the most appropriate time to sample the microcosms after chemical application. Nematode abundance was reduced after exposure to copper at 100 {micro}g/g, with fungivore, bacterivore, and omnivore-predator nematodes being the most sensitive groups. Cadmium did not affect the nematode or microarthropod communities. Microarthropods were far more sensitive to malathion than were nematodes, and total microarthropod abundance was lower than controls at 400 {micro}g/g. Prostigmatid mites and other arthropods were the most affected groups. PCB also had a greater negative impact on microarthropods than on nematodes. Total microarthropod abundance declined at 2,500 {micro}g/g, with prostigmatid and oribatid mites exhibiting the highest susceptibility. Strong differential sensitivity between nematode and microarthropod communities indicates that both groups should be examined to fully evaluate the biological impact of chemicals on soils. The authors conclude that microcosms with field-collected soil microfaunal communities offer high resolution of the ecotoxicologic effects of chemicals in complex soil systems.

A key objective in ecology is to understand how cooperative strategies evolve and are maintained in species networks. Here, we focus on the tri-trophic relationship between arbuscular mycorrhizal (AM) fungi, host plants, and fungivores to ask if host plants are able to protect their mutualistic mycorrhizal partners from being grazed. Specifically, we test whether secondary metabolites are transferred from hosts to fungal partners to increase their defense against fungivores. We grew Plantago lanceolata hosts with and without mycorrhizal inoculum, and in the presence or absence of fungivorous springtails. We then measured fungivore effects on host biomass and mycorrhizal abundance (using quantitative PCR) in roots and soil. We used high-performance liquid chromatography to measure host metabolites in roots, shoots, and hyphae, focusing on catalpol, aucubin, and verbascoside. Our most striking result was that the metabolite catalpol was consistently found in AM fungal hyphae in host plants exposed to fungivores. When fungivores were absent, catalpol was undetectable in hyphae. Our results highlight the potential for plant-mediated protection of the mycorrhizal hyphal network. © 2013 by the Ecological Society of America.

A microcosm technique is presented that uses community and trophic-level analysis of soil nematodes and microarthropods to determine the effects of chemicals on soil systems. Forest soil was treated with either copper (0, 100, 200, 400, and 600 mg g−1), p-nitrophenol (0, 20, 40, 80, and 160 mg g−1), or trinitrotoluene (0, 25, 50, 100, and 200 mg g−1). Nematodes were sorted into bacterivore, fungivore, herbivore, and omnivore-predator trophic groups, and a hatchling category. Microarthropods were sorted to the acarine suborders Prostigmata, Mesostigmata, and Oribatida; the insectan order Collembola; and a miscellaneous group. Omnivore-predator nematodes and mesostigmatid and oribatid mites were the groups most sensitive to copper and were significantly reduced at levels as low as 100 mg g−1 copper. Total nematode and microarthropod numbers declined above 200 mg g−1 copper. Trophic structure analysis suggested that high sensitivity of nematode predators to intermediate levels of copper reduced predation on herbivore nematodes and resulted in greater numbers of nematodes compared to controls. p-Nitrophenol was very toxic to the nematode community, and all trophic groups were significantly reduced above 20 mg g−1. However, there was no effect of p-nitrophenol on microarthropods. Trinitrotoluene had no significant negative effect on total abundance of either group of soil fauna, but oribatids were significantly reduced at 200 mg g−1. Our results demonstrated that soil nematodes and microarthropods were sensitive indicators of environmental contaminants and that trophic-structure and community analysis has the potential to detect more subtle indirect effects of chemicals on soil food-web structure. We conclude that microcosms with field communities of soil microfauna offer high resolution of the ecotoxicological effects of chemicals in complex soil systems.

The compensatory growth potential of a grazed fungal biomass was mathematically expressed as a function of patchiness in its distribution and demonstrated in an experiment using the fungivorous collembolan Onychiurus armatus and the soil fungi Verticillium bulbillosum and Penicillium spinulosum. The model addresses the regrowth potential in relation to patch fragmentation, travelling time and consumption rate of the collembolan and the mean relative growth rate of the fungus. It suggests that the mean relative growth rate required for regrowth decreases with patch fragmentation and increases with the mean growth rate of the fungus. The experiments were performed with a system of soil-filled vials provided with fungi and collembolans. The size of the vials and the length of the tubes connecting them were varied to give different patch sizes and travelling times. The respiratory activity of fungi after grazing increased as a unit of mycelium was distributed into smaller connected vials. The slow growing species V. bulbillosum showed a greater but delayed response to grazing in comparison with the fast growing P. spinulosum. An increased travelling time delayed the growth response in both species.

Extensive natural mushroom cultivations of Pleurotus eryngii (DC.) Quél. were studied in their main productive area, the northwest of Segovia province, Spain, identifying a new parasite for this fungus, Tarnania fenestralis (Meigen, 1818) (Diptera: Micetophilidae). The prevalence of parasitization reaches 20.4% of the yield, the main damage being in the destruction of internal tissues of the carpophores, resulting in crop depreciation. Due to the high incidence of parasitization by the dipteran in the mushroom, as well as its abundance, the nematocerous fungivore T. fenestralis may be considered the main and most important parasite of extensive P. eryngii productions of all the zone in which the investigation is made., En el estudio de los parásitos que afectan a las producciones extensivas naturales de seta de cardo Pleurotus eryngii (DC.) Quél. en su principal área productiva: noroeste de Segovia, España; se identifica un nuevo parásito para este hongo, Tarnania fenestralis (Meigen, 1818) (Diptera: Micetophilidae). La prevalencia de parasitación encontrada es un 20,4% de la producción y su principal daño radica en la destrucción de los tejidos internos de los carpóforos, depreciando este recurso. Debido a la alta incidencia de parasitaciones del díptero en la seta, así como su abundancia, se considera al nematócero fungívoro T. fenestralis cómo el principal y más importante parásito de las producciones extensivas de P. eryngii de toda la zona en la que se realiza la investigación.

We conducted field experiments to test the general hypothesis that the com- position of decomposer communities and their trophic interactions can influence patterns of plant litter decomposition and nitrogen dynamics in ecosystems. Conventional (CT) and no-tillage (NT) agroecosystems were used to test this idea because of their structural sim- plicity and known differences in their functional properties. Biocides were applied to ex- perimentally exclude bacteria, saprophytic fungi, and microarthropods in field exclosures. Abundances of decomposer organisms (bacteria, fungi, protozoa, nematodes, microar- thropods), decomposition rates, and nitrogen fluxes were quantified in surface and buried litterbags (Secale cereale litter) placed in both NT and CT systems. Measurements of in situ soil respiration rates were made concurrently. The abundance and biomass of all microbial and faunal groups were greater on buried than surface litter. The mesofauna contributed more to the total heterotrophic C in buried litter from CT (6-22%) than in surface litter from NT (0.4-1/1%). Buried litter decay rates (1.4-1.7%/d) were -2.5 times faster than rates for surface litter (0.5-O.7%/d). Ratios of fungal to bacterial biomass and fungivore to bacterivore biomass on NT surface litter generally increased over the study period resulting in ratios that were 2.7 and 2.2 times greater, respectively, than those of CT buried litter by the end of the summer. The exclusion experiments showed that fungi had a somewhat greater influence on the decomposition of surface litter from NT while bacteria were more important in the de- composition of buried litter from CT. The fungicide and bactericide reduced decomposition rates of NT surface litter by 36 and 25% of controls, respectively, while in CT buried litter they were reduced by 21 and 35% of controls, respectively. Microarthropods were more important in mobilizing surface litter nitrogen by grazing on fungi than in contributing to litter mass loss. Where fungivorous microarthropods were experimentally excluded, there was less than a 5% reduction in mass loss from litter of both NT and CT, but fungi- fungivore interactions were important in regulating litter N dynamics in NT surface litter. As fungal densities increased following the exclusion of microarthropods on NT surface litter, there was 25% greater N retention as compared to the control after 56 d of decay. Saprophytic fungi were responsible for as much as 86% of the net N immobilized (1.81 g /m2) in surface litter by the end of the study when densities of fungivorous microarthropods were low. Although bacteria were important in regulating buried litter decomposition rates and the population dynamics of bacterivorous fauna, their influence on buried litter N dynamics remains less clear. The larger microbial biomass and greater contribution of a bacterivorous fauna on buried litter is consistent with the greater carbon losses and lower carbon assimilation in CT than NT agroecosystems. In summary, our results suggest that litter placement can strongly influence the com- position of decomposer communities and that the resulting trophic relationships are im- portant to determining the rates and timing of plant litter decomposition and N dynamics. Furthermore, cross placement studies suggest that the decomposer communities within each tillage system, while not discrete, are adapted to the native litter placements in each.

An assessment of the insect guild structure associated with immature and mature eastern hemlock, Tsuga canadensis (L.) Carriere, at high and low elevations was made before the invasion by the hemlock woolly adelgid, Adelges tsugae (Annand), and elongate hemlock scale, Fiorinia externa Ferris. Guild dynamics were determined among 243 insect species associated with eastern hemlock in the southern Appalachians. Detritivore, hematophage, herbivore, fungivore, parasitoid, predator, scavenger, and transient guild assignments were made. The herbivore and transient guilds were subdivided into chewers, sapsuckers, flower feeders, pollen feeders, pollen/nectar/sap feeders, and seed feeders. A significant association was found between guilds on immature and mature hemlocks at low elevations, but no significant association was found at high elevations. There was also a strong association of phytophagous insects on immature hemlocks and scavengers on mature hemlocks. The observed transient, scavenger, and predator guilds had a significantly lower co-occurrence among species indicating segregation of the species within these guilds. The herbivore guild had a significantly higher co-occurrence among species than the simulated index indicating aggregation of species within this guild across sites. Detritivore, hematophage, and parasitoid guilds did not differ significantly from the simulated community. These results document a diverse and dynamic insect community on eastern hemlock before invasion by hemlock woolly adelgid and elongate hemlock scale.

This review analyses the phenomenon of bacterial mycophagy, which we define as a set of phenotypic behaviours that enable bacteria to obtain nutrients from living fungi and thus allow the conversion of fungal into bacterial biomass. We recognize three types of bacterial strategies to derive nutrition from fungi: necrotrophy, extracellular biotrophy and endocellular biotrophy. Each is characterized by a set of uniquely sequential and differently overlapping interactions with the fungal target. We offer a detailed analysis of the nature of these interactions, as well as a comprehensive overview of methodologies for assessing and quantifying their individual contributions to the mycophagy phenotype. Furthermore, we discuss future prospects for the study and exploitation of bacterial mycophagy, including the need for appropriate tools to detect bacterial mycophagy in situ in order to be able to understand, predict and possibly manipulate the way in which mycophagous bacteria affect fungal activity, turnover, and community structure in soils and other ecosystems.

To date, research on the effects of forest defoliator outbreaks and pesticide applications to suppress these outbreaks on non-target forest arthropods has generally focused on non-target Lepidoptera and has not examined effects on regional diversity. In this study, we assessed the effects of forest defoliation by gypsy moths and application of the microbial pesticide Bacillus thuringiensis var. kurstaki (Btk) to suppress gypsy moth populations on the species richness and (Shannon index) diversity of beetles in Shenandoah National Park, Virginia. In addition, we examined how these disturbances affected overall beetle abundance and abundances within different feeding guilds (herbivore, predator, fungivore, or xylophage). Three years after a gypsy moth outbreak, beetles were sampled four times throughout spring and summer at 15 sites belonging to one of three disturbance histories: undisturbed, defoliated, or sprayed with Btk. Beetles were captured using blacklight traps and then sorted to family and morphos...

Theory predicts that spatial structure can mediate interactions that affect species diversity in a patchy environment. A rarely considered effect of spatial structure on biodiversity is the interplay of spatial habitat arrangement with species interactions at multiple spatial scales. We investigated how spatial habitat arrangement and predation mediate the assembly of the larval communities of fungivorous insects breeding in the oyster mushroom, Pleurotus ostreatus (Jacq. ex Fr.) P.Kumm in a North American woodland. In a two-way factorial design, we varied the spatial arrangement of mushroom clumps (‘clustered', ‘patchy', and ‘uniform'; 3 levels) crossed with predator exclusion (access allowed or not; 2 levels) to study their joint effects on patterns of α, β and γ diversity of the fungivorous insect communities. Partitioning diversity into these three components suggested that neither spatial nor predation treatments significantly affected α, β and γ diversity. We found that an intermediate inter-clump d...