Differences between bacterial communities in the gut of a soil-feeding termite (Cubitermes niokoloensis) and its mounds

In tropical ecosystems, termite mound soils constitute an important soil compartment covering around 10% of African soils. Previous studies have shown (S. Fall, S. Nazaret, J. L. Chotte, and A. Brauman, Microb. Ecol. 28:191-199, 2004) that the bacterial genetic structure of the mounds of soil-feeding termites (Cubitermes niokoloensis) is different from that of their surrounding soil. The aim of this study was to characterize the specificity of bacterial communities within mounds with respect to the digestive and soil origins of the mound. We have compared the bacterial community structures of a termite mound, termite gut sections, and surrounding soil using PCR-denaturing gradient gel electrophoresis (DGGE) analysis and cloning and sequencing of PCR-amplified 16S rRNA gene fragments. DGGE analysis revealed a drastic difference between the genetic structures of the bacterial communities of the termite gut and the mound. Analysis of 266 clones, including 54 from excised bands, revealed a high level of diversity in each biota investigated. The soil-feeding termite mound was dominated by the Actinobacteria phylum, whereas the Firmicutes and Proteobacteria phyla dominate the gut sections of termites and the surrounding soil, respectively. Phylogenetic analyses revealed a distinct clustering of Actinobacteria phylotypes between the mound and the surrounding soil. The Actinobacteria clones of the termite mound were diverse, distributed among 10 distinct families, and like those in the termite gut environment lightly dominated by the Nocardioidaceae family. Our findings confirmed that the soil-feeding termite mound (C. niokoloensis) represents a specific bacterial habitat in the tropics.     

Bacterial Density and Community Structure Associated with Aggregate Size Fractions of Soil-Feeding Termite Mounds

The building and foraging activities of termites are known to modify soil characteristics such as the heterogeneity. In tropical savannas the impact of the activity of soil-feeding termites (Cubitermes niokoloensis) has been shown to affect the properties of the soil at the aggregate level by creating new soil microenvironments (aggregate size fractions) [13]. These changes were investigated in greater depth by looking at the microbial density (AODC) and the genetic structure (automated rRNA intergenic spacer analysis: ARISA) of the communities in the different aggregate size fractions (i.e., coarse sand, fine sand, coarse silt, fine silt, and dispersible clays) separated from compartments (internal and external wall) of three Cubitermes niokoloensis mounds. The bacterial density of the mounds was significantly higher (1.5 to 3 times) than that of the surrounding soil. Within the aggregate size fractions, the termite building activity resulted in a significant increase in bacterial density within the coarser fractions (>20 m). Multivariate analysis of the ARISA profiles revealed that the bacterial genetic structures of unfractionated soil and soil aggregate size fractions of the three mounds was noticeably different from the savanna soil used as a reference. Moreover, the microbial community associated with the different microenvironments in the three termite mounds revealed three distinct clusters formed by the aggregate size fractions of each mound. Except for the 2–20 m fraction, these results suggest that the mound microbial genetic structure is more dependent upon microbial pool affiliation (the termite mound) than on the soil location (aggregate size fraction). The causes of the specificity of the microbial community structure of termite mound aggregate size fractions are discussed.This revised version was published online in November 2004 with corrections to Volume 48.     

Phylogenetic Analysis of the Gut Bacterial Microflora of the Fungus-Growing Termite Odontotermes formosanus

We constructed a bacterial 16S rRNA gene clone library from the gut microbial community of O. formosanus and phylogenetically analyzed it in order to contribute to the evolutional study of digestive symbiosis and method development for termite control. After screening by restriction fragment length polymorphism (RFLP) analysis, 56 out of 280 clones with unique RFLP patterns were sequenced and phylogenetically analyzed. The representative phylotypes were affiliated to four phylogenetic groups, Firmicutes, the Bacteroidetes/Chlorobi group, Proteobacteria, and Actinobacteria of the domain Bacteira. No one clone affiliated with the phylum Spirochaetes was identified, in contrast to the case of wood-feeding termites. The phylogenetic analysis revealed that nearly half of the representative clones (25 phylotypes) formed monophyletic clusters with clones obtained from other termite species, especially with the sequences retrieved from fungus-growing termites. These results indicate that the presence of termite-specific bacterial lineages implies a coevolutional relationship of gut microbes and host termites.     

Axial Dynamics, Stability, and Interspecies Similarity of Bacterial Community Structure in the Highly Compartmentalized Gut of Soil-Feeding Termites (Cubitermes spp.)

The highly compartmentalized gut of soil-feeding termites is characterized by pronounced axial dynamics in physicochemical conditions and microbial processes. In a companion paper (D. Schmitt-Wagner, M. W. Friedrich, B. Wagner, and A. Brune, Appl. Environ. Microbiol. 69:6007-6017, 2003), we demonstrated that the variety of physicochemical conditions in the different gut compartments of Cubitermes spp. is reflected in the diversity of the respective intestinal microbial communities. Here, we used molecular fingerprints of 16S rRNA genes of the bacterial community, obtained by terminal restriction fragment length polymorphism (T-RFLP) analysis, to describe the axial dynamics of the bacterial community structure in the different gut sections. Comparison of the T-RFLP profiles with the predicted terminal restriction fragments of the clones in clone libraries of the gut segments in Cubitermes orthognathus confirmed that all hindgut sections harbored distinct bacterial communities. Morisita indices of community similarity, calculated by comparing the different patterns, revealed large differences between the bacterial communities of soil, gut, and nest material and also among the individual gut sections. By contrast, comparison of the homologous gut segments of different Cubitermes species indicated that the three termite species investigated possessed a similar, gut-specific microbiota that remained comparatively stable even during several months of maintenance in the laboratory.     

Intra- and Interspecific Comparisons of Bacterial Diversity and Community Structure Support Coevolution of Gut Microbiota and Termite Host

We investigated the bacterial gut microbiota from 32 colonies of wood-feeding termites, comprising four Microcerotermes species (Termitidae) and four Reticulitermes species (Rhinotermitidae), using terminal restriction fragment length polymorphism analysis and clonal analysis of 16S rRNA. The obtained molecular community profiles were compared statistically between individuals, colonies, locations, and species of termites. Both analyses revealed that the bacterial community structure was remarkably similar within each termite genus, with small but significant differences between sampling sites and/or termite species. In contrast, considerable differences were found between the two termite genera. Only one bacterial phylotype (defined with 97% sequence identity) was shared between the two termite genera, while 18% and 50% of the phylotypes were shared between two congeneric species in the genera Microcerotermes and Reticulitermes, respectively. Nevertheless, a phylogenetic analysis of 228 phylotypes from Microcerotermes spp. and 367 phylotypes from Reticulitermes spp. with other termite gut clones available in public databases demonstrated the monophyly of many phylotypes from distantly related termites. The monophyletic “termite clusters” comprised of phylotypes from more than one termite species were distributed among 15 bacterial phyla, including the novel candidate phyla TG2 and TG3. These termite clusters accounted for 95% of the 960 clones analyzed in this study. Moreover, the clusters in 12 phyla comprised phylotypes from more than one termite (sub)family, accounting for 75% of the analyzed clones. Our results suggest that the majority of gut bacteria are not allochthonous but are specific symbionts that have coevolved with termites and that their community structure is basically consistent within a genus of termites.     

Mulga log mounds: Fertile patches in the semi-arid woodlands of eastern Australia

In the semi-arid woodland of eastern Australia, soil mounds are often associated with fallen mulga (Acacia aneura) trees. Measurements of the physical and chemical properties of the soils in these mounds compared with surrounding soils, together with differences in herbage growth responses, indicate that these mounds are fertile patches, with possible importance as habitats for soil fauna and as refugia for a range of organisms during drought. The mound soil material may accumulate by fluvial, aeolian or rain-splash deposition about the fallen log, however, some of the mound material was derived from termite feeding gallery structures. The surface feeding gallery material may be comprised of soil particles from within the mound or from tunnels and storage galleries below the mound, and probably depends on the termite species.     

Effects of Erosion from Mounds of Different Termite Genera on Distinct Functional Grassland Types in an African Savannah

A key aspect of savannah vegetation heterogeneity is mosaics formed by two functional grassland types, bunch grasslands, and grazing lawns. We investigated the role of termites, important ecosystem engineers, in creating high-nutrient patches in the form of grazing lawns. Some of the ways termites can contribute to grazing lawn development is through erosion of soil from aboveground mounds to the surrounding soil surface. This may alter the nutrient status of the surrounding soils. We hypothesize that the importance of this erosion varies with termite genera, depending on feeding strategy and mound type. To test this, we simulated erosion by applying mound soil from three termite genera (Macrotermes, Odontotermes, and Trinervitermes) in both a field experiment and a greenhouse experiment. In the greenhouse experiment, we found soils with the highest macro nutrient levels (formed by Trinervitermes) promoted the quality and biomass of both a lawn (Digitaria longiflora) and a bunch (Sporobolus pyramidalis) grass species. In the field we found that soils with the highest micro nutrient levels (formed by Macrotermes) showed the largest increase in cover of grazing lawn species. By linking the different nutrient availability of the mounds to the development of different grassland states, we conclude that the presence of termite mounds influences grassland mosaics, but that the type of mound plays a crucial role in determining the nature of the effects.     

Isolation of facultatively aerobic actinomycetes from the gut, parent soil and mound materials of the termites Procubitermesaburiensis and Cubitermes severus

Abstract Isolates of the genus Streptomyces were readily obtained from the intestines of two African species of soil-feeding termites by an aerobic explant technique using starch casein medium, and from their parent soil and mound materials by dilution plating. Discriminant analysis of the isolates, based on 44 representative characters, showed that the population derived directly from the termites was significantly different from that of the feed soil or the mound. The termite gut was considered to be a good source of unusual actinomycetes, but strains isolated under aerobic conditions are likely to be allochthons selected by the intestinal environment, which is highly alkaline and anaerobic. An anaerobic, filamentous isolate was obtained which may be a component of the prokaryotic symbiont population mediating termite digestion.     

Nutrient dynamics and plant assemblages of Macrotermes falciger mounds in a savanna ecosystem

Termites through mound construction and foraging activities contribute significantly to carbon and nutrient fluxes in nutrient-poor savannas. Despite this recognition, studies on the influence of termite mounds on carbon and nitrogen dynamics in sub-tropical savannas are limited. In this regard, we examined soil nutrient concentrations, organic carbon and nitrogen mineralization in incubation experiments in mounds of Macrotermes falciger and surrounding soils of sub-tropical savanna, northeast Zimbabwe. We also addressed whether termite mounds altered the plant community and if effects were similar across functional groups i.e. grasses, forbs or woody plants. Mound soils had significantly higher silt and clay content, pH and concentrations of calcium (Ca), magnesium (Mg), potassium (K), organic carbon (C), ammonium (NH₄⁺) and nitrate (NO₃⁻) than surrounding soils, with marginal differences in phosphorus (P) and sodium (Na) between mounds and matrix soils. Nutrient enrichment increased by a factor ranging from 1.5 for C, 4.9 for Mg up to 10.3 for Ca. Although C mineralization, nitrification and nitrification fraction were similar between mounds and matrix soils, nitrogen mineralization was elevated on mounds relative to surrounding matrix soils. As a result, termite mounds supported unique plant communities rich and abundant in woody species but less diverse in grasses and forbs than the surrounding savanna matrix in response to mound-induced shifts in soil parameters specifically increased clay content, drainage and water availability, nutrient status and base cation (mainly Ca, Mg and Na) concentration. In conclusion, by altering soil properties such as texture, moisture content and nutrient status, termite mounds can alter the structure and composition of sub-tropical savanna plant communities, and these results are consistent with findings in other savanna systems suggesting that increase in soil clay content, nutrient status and associated changes in the plant community assemblage may be a general property of mound building termites.     

Methane emission by termites and oxidation by soils, across a forest disturbance gradient in the Mbalmayo Forest Reserve, Cameroon

Methane fluxes were measured, using static chambers, across a disturbance gradient in a West African semi-deciduous humid forest. Soil-feeding termite biomass was simultaneously determined, in an attempt to examine its influence on the net soil-atmosphere exchange of CH₄. CH₄ emission rates from individual termite species were determined under laboratory conditions, permitting the gross production of CH₄ to be compared with net fluxes to the atmosphere. Both net CH₄ oxidation(-) and emission were observed, and CH₄ fluxes ranged from – 24.6 to 40.7 ng m^–2 s^–1. A statistically significant relationship between termite biomass and CH₄ flux was observed across the forested sites such that: CH₄ flux (ng m^–2 s^–1) = 4.95 × termite biomass (gm^–2)–10.9 (P < 0.001). Rates of CH₄ oxidation were on average 60% smaller at the clearfelled and Terminalia plantation sites than at the near-primary forest site. Two of the disturbed sites were net CH₄ sources during one of the sampling periods. Disturbance of tropical forests, resulting in a decrease in the CH₄ sink capacity of the soil, may therefore increase the contribution of termite-derived CH₄ to the atmosphere. Measurements from the mounds of the soil-feeding termites Thoracotermes macrothorax and Cubitermes fungifaber from the old plantation site gave a CH₄ emission of 636 and 53.4 ng s^–1 mound^–1, respectively. The forest floor surrounding the mounds was sampled in three concentric bands. Around the mound of T. macrothorax the soil was a net source of CH₄ estimated to contribute a further 148 ng s^–1. Soil surrounding the mound of C. fungifaber was mostly a net sink. The mounds of soil-feeding termites are point sources of CH₄, which at the landscape scale may exceed the general sink capacity of the soil, to an extent dependent on seasonal variations in soil moisture and level of disturbance.     

Termite Mounds Increase Functional Diversity of Woody Plants in African Savannas

Fine-scale spatial heterogeneity influences biodiversity and ecosystem productivity at many scales. In savanna systems, Macrotermes termites, through forming spatially explicit mounds with unique woody plant assemblages, emerge as important sources of such heterogeneity. Despite a growing consensus regarding the importance of functional diversity (FD) to ecosystem processes, no study has quantified how termite mounds affect woody plant FD. We address whether termite mounds alter the distribution of functional traits, and increase FD of woody plant communities within Africa’s largest savanna woodland, the 2.7 million km² miombo system. Using plant traits that change according to soil resources (for example, water and nutrients), and disturbance (for example, fire and elephant herbivory), we identified response functional groups and compared relative representation of these groups between mound and matrix habitats. We also asked whether mound and matrix habitats differed in their contribution to FD within the system. Although species representing most functional groups were found in both mound and matrix habitats, relative abundance of functional groups differed between mound and matrix. Mound plant assemblages had greater response diversity to soil resources than matrix plots, but there was no difference in response diversity to disturbance. High trait values on mounds included tree height, leaf nitrogen, phosphorus, and palatability. Species with root ectomycorrhizae dominated the matrix. In conclusion, these small patches of nutrient-enriched substrate emerge as drivers of FD in above-ground woody plant communities.     

Gut-specific actinobacterial community structure and diversity associated with the wood-feeding termite species, Nasutitermes corniger (Motschulsky) described by nested PCR-DGGE analysis

This comprehensive survey studied the actinobacterial community structure and putative representative members associated with the gut of the wood-feeding termite, Nasutitermes corniger (Motschulsky), using nested PCR-DGGE and 16S rDNA sequences analyses. The closest relatives of the actinobacteria inhabiting the gut of Nasutitermes corniger were in five families, regardless of the geographical origin of the termite colony: Propionibacteriaceae, Streptomycetaceae, Cellulomonodaceae, Corynebacteriaceae and Rubrobacteraceae. Feeding termites on beech wood did not result in substantial changes in the actinobacterial community structure as revealed by DGGE banding patterns. Most of the 16S rDNA sequences obtained after excision and sequencing of DGGE bands clustered with those previously retrieved in termite guts. These results confirm the presence of gut-specific actinobacteria. Except for the 16S rDNA sequences affiliated to Streptomycetaceae and Cellulomonodaceae, no sequence had more than 97% similarity with the closest isolated strains, indicating the presence of microorganisms that have not yet been cultivated. These results suggest that members of the Actinomycetales order account for the largest proportion of the Actinobacteria phylum inhabiting the gut of the termite N. corniger.     

Role of termites in the restoration of soils and plant richness on bowé in West Africa

Bowé (hardened ferricrete soils formed by erosion, drought or deforestation) are often associated with termite mounds, but little is known about these mounds and their role in the restoration of soils and plant biodiversity on bowé. This study examined termite mounds on bowé and their effects on soil depth and plant richness. Sixty-four sampling plots were laid out randomly on bowé sites with mounds and on adjacent bowé sites without mounds. The height and circumference of each mound were measured. Species inventories were made and soil depth measured in each plot. Linear mixed effects and generalised mixed effects models with Poisson error distribution were used to assess the variation in soil depth and plant species richness in mound and nonmound microsites. Two types of mounds (small vs. large) associated with different termite species were observed on bowé, with the small mounds being most common. Plots with either large or small mounds had deeper soils and higher plant richness than the adjacent plots without mounds. Conservation of termite mounds is important for restoring soils and plant richness on bowé, and termite mounds should be taken into consideration in biodiversity and soil management strategies for bowé.     

Influence of Feed Components on Symbiotic Bacterial Community Structure in the Gut of the Wood-Feeding Higher Termite Nasutitermes takasagoensis

The influence of carbon sources on bacterial community structure in the gut of the wood-feeding higher termite Nasutitermes takasagoensis was investigated. 16S rRNA gene sequencing and terminal-restriction fragment length polymorphism (T-RFLP) analyses revealed that the bacterial community structure changed markedly depending on feed components at the phylum level. Spirochaetes was predominant in the clone libraries from wood- and wood powder-fed termites, whereas Bacteroidetes was the largest group in the libraries from xylan-, cellobiose-, and glucose-fed termites, and Firmicutes was predominant in the library from xylose-fed termites. In addition, clones belonging to the phylum Termite Group I (TG1) were found in the library from xylose-fed termites. Our results indicate that the symbiotic relationship between termite and gut microorganisms is not very strong or stable over a short time, and that termite gut microbial community structures vary depending on components of the feeds.     

Application of 13C NMR to investigate the transformations and biodegradation of organic materials by wood- and soil-feeding termites, and a coprophagous litter-dwelling dipteran larva

Solid-state 13C nuclear magnetic resonance spectroscopy has been used to characterize the C in samples of the food (wood), gut contents and faeces from the wood-feeding termite, Microcerotermes parvus; soil in the guts and mound material from the soil-feeding termite, Thoracotermes macrothorax; and the food and faeces from the litter-feeding, coprophagous larvae of the dipteran fly, Bibio marci. Spectra from the wood-feeding termite indicated preferential loss of polysaccharide and accumulation of lignin with some modification to the O-aromatic-C and methoxyl-C (O-methyl-C) components during passage through the gut. Spectra for the soil-feeding termite indicated little change in the distribution of 13C between resonances following passage through the gut, except for some evidence of preferential polysaccharide loss. Interpretation of the spectra from these organisms was restricted by the relatively low C content of the soils and mound material, and by the large contribution to the NMR spectra from the gut tissue rather than the gut contents. Spectra for the litter-feeding dipteran larvae indicated preferential feeding on the polysaccharide-rich component of the litter and then overall loss of polysaccharide-C and accumulation of both aromatic-C and methoxyl-C in the gut. These changes were greater for the second passage than for the first passage through the gut, suggesting that principally mechanical and physical changes occurred initially and that chemical digestion was prevalent during the second passage.     

Termite mound density and distribution patterns across three land-use types in the Vhembe District of the Limpopo Province,South Africa

This study investigated the effect of land-use on density and distribution patterns of termite mounds. A total area of 12 ha was investigated using four 1 ha plots from each of three land-use types (mango orchards, maize fields and communal rangelands). A total of 297 mounds from four termite species were recorded. Plotted GIS coordinates for each mound in ArcMap showed a random distribution pattern in all land-use types. The mean number of mounds per hectare was significantly higher (p < 0.001) in communal rangelands (52.5 ± 1.21), than in maize fields (14.75 ± 3.15) and mango orchards (7.5 ± 0.87), and dominated by small-sized mounds of Trinervitermes sp. Few mounds of Odontotermes sp. were found. Mounds of the edible termites, Macrotermes natalensis and M. falciger, were found in all land-use types, with the highest density for both species being in maize fields. Although the mound height for both species was similar, mound circumference for M. falciger was significantly larger (p < 0.001) which may limit land available for agricultural use. Density of mounds was influenced by land-use which may lead to changes in termite ecosystem functioning and availability of termites as a free source of protein.     

Comparison of Euryarchaea Strains in the Guts and Food-Soil of the Soil-Feeding Termite Cubitermes fungifaber across Different Soil Types

Termites are an important component of tropical soil communities and have a significant effect on the structure and nutrient content of soil. Digestion in termites is related to gut structure, gut physicochemical conditions, and gut symbiotic microbiota. Here we describe the use of 16S rRNA gene sequencing and terminal-restriction fragment length polymorphism (T-RFLP) analysis to examine methanogenic archaea (MA) in the guts and food-soil of the soil-feeder Cubitermes fungifaber Sjostedt across a range of soil types. If these MA are strictly vertically inherited, then the MA in guts should be the same in all individuals even if the soils differ across sites. In contrast, gut MA should reflect what is present in soil if populations are merely a reflection of what is ingested as the insects forage. We show clear differences between the euryarchaeal communities in termite guts and in food-soils from five different sites. Analysis of 16S rRNA gene clones indicated little overlap between the gut and soil communities. Gut clones were related to a termite-derived Methanomicrobiales cluster, to Methanobrevibacter and, surprisingly, to the haloalkaliphile Natronococcus. Soil clones clustered with Methanosarcina, Methanomicrococcus, or rice cluster I. T-RFLP analysis indicated that the archaeal communities in the soil samples differed from site to site, whereas those in termite guts were similar between sites. There was some overlap between the gut and soil communities, but these may represent transient populations in either guts or soil. Our data do not support the hypothesis that termite gut MA are derived from their food-soil but also do not support a purely vertical transmission of gut microflora.     

Deciphering earth mound origins in central Brazil

Mound fields are a common landscape throughout the world and much of the evidence for their origin has been of a circumstantial nature. It has been hypothesized that earth mounds emerge over grasslands by termite activity; alternatively, they might be formed after erosion. We tested whether a mound field in central Brazil was generated by termite activity or erosion. We used soil organic matter isotopic composition, soil chemical, physical and floristic composition to determine the origin of a mound field. If the mounds emerged by termite activity in an established grassland the soil organic matter below the mound should have the isotopic signature of C₄ dominated grassland, which contrasts with savanna C₃ + C₄ signature. Additionally, soil traits should resemble those of the grassland. All markers indicate that the mounds were formed by erosion. The soil isotopic composition, chemical traits and texture below the mound resembled those of the savanna and not those of the grassland. Moreover, most of the species present in the mound were typical of savanna. Concrete evidence is provided that mound fields in the studied area were produced by erosion of a savanna ecosystem and not termite activity. The use of the techniques applied here would improve the assessments of whether analogous landscapes are of a biogenic nature or not.     

Nitrogen mineralization, denitrification, and nitrate ammonification by soil-feeding termites: a 15N-based approach

Soil-feeding termites are abundant and play important roles in the biogeochemical processes in tropical soils. Previous studies indicated that they preferentially utilize the peptidic components of soil organic matter as a nutrient resource. Here, we determined the corresponding mineralization fluxes and elucidated other N transformation processes that occur during soil gut passage using ¹⁵N tracer techniques. Termite-based rates of N mineralization by Cubitermes umbratus and Cubitermes ugandensis in soil microcosms amended with ¹⁵NH₄ ⁺ were 6.6 and 9.2 nmol N day^?1 (g fresh wt)^?1, which means that the soil peptides fuel about 20 and 40% of the respiratory activity of these insects. Considering the areal biomass of soil-feeding termites in humid savannahs, soil-feeding termites should mineralize about 3% of the total N in their food soil per year. In addition to producing ammonia from ingested ¹⁵NO₃ ^? at approximately 10% of the mineralization rate, C. umbratus also formed N₂ at similar rates. The formation of labelled N₂ in microcosms amended with ¹⁵NH₄ ⁺ seems to be at least partially due to nitrification activity in the soil; evidence for the formation of nitrate in the posterior hindgut remains inconclusive. However, the so far unexplained increase of ¹⁵N abundance in the ammonia pools of the posterior hindgut compartments manifests additional hitherto unknown metabolic processes in this gut region. Collectively, our results not only reinforce the concept of nitrogenous soil components as an important dietary resource for soil-feeding termites, but also allow us to predict that N mineralization and nitrate ammonification activities in the termite gut should positively affect the dynamics of N in tropical soil.     

Axial dynamics, stability, and interspecies similarity of bacterial community structure in the highly compartmentalized gut of soil-feeding termites (Cubitermes spp.)

The highly compartmentalized gut of soil-feeding termites is characterized by pronounced axial dynamics in physicochemical conditions and microbial processes. In a companion paper (D. Schmitt-Wagner, M. W. Friedrich, B. Wagner, and A. Brune, Appl. Environ. Microbiol. 69:6007-6017, 2003), we demonstrated that the variety of physicochemical conditions in the different gut compartments of Cubitermes spp. is reflected in the diversity of the respective intestinal microbial communities. Here, we used molecular fingerprints of 16S rRNA genes of the bacterial community, obtained by terminal restriction fragment length polymorphism (T-RFLP) analysis, to describe the axial dynamics of the bacterial community structure in the different gut sections. Comparison of the T-RFLP profiles with the predicted terminal restriction fragments of the clones in clone libraries of the gut segments in Cubitermes orthognathus confirmed that all hindgut sections harbored distinct bacterial communities. Morisita indices of community similarity, calculated by comparing the different patterns, revealed large differences between the bacterial communities of soil, gut, and nest material and also among the individual gut sections. By contrast, comparison of the homologous gut segments of different Cubitermes species indicated that the three termite species investigated possessed a similar, gut-specific microbiota that remained comparatively stable even during several months of maintenance in the laboratory.