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In tropical rainforests, termites constitute an important part of the soil fauna biomass, and as for other soil arthropods, variations in soil composition create opportunities for niche partitioning. The aim of this study was twofold: first, we tested whether soil-feeding termite species differ in the foraging substrate; second, we investigated whether soil-feeding termites select their foraging sites to enhance nutrients intake. To do so, we collected termites and analysed the composition and structure of their feeding substrates. Although Anoplotermes-group members are all considered soil-feeders, our results show that some species specifically feed on abandoned termite nests and very rotten wood, and that this substrate selection is correlated with previous stable isotope analyses, suggesting that one component of niche differentiation among species is substrate selection. Our results show that the composition and structure of bare soils on which different termite species foraged do not differ, suggesting that there is no species specialization for a particular type of bare soil. Finally, the bare soil on which termites forage does not differ from random soil samples. Overall, our results suggest that few species of the Anoplotermes-group are specialized toward substrates rich in organic matter, but that the vast majority forage on soil independently of its structural and chemical composition, being ecologically equivalent for this factor.
- MeSH
- deštný prales * MeSH
- Isoptera fyziologie MeSH
- půda * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The decomposition of wood and detritus is challenging to most macroscopic organisms due to the recalcitrant nature of lignocellulose. Moreover, woody plants often protect themselves by synthesizing toxic or nocent compounds which infuse their tissues. Termites are essential wood decomposers in warmer terrestrial ecosystems and, as such, they have to cope with high concentrations of plant toxins in wood. In this paper, we evaluated the influence of wood age on the gut microbial (bacterial and fungal) communities associated with the termites Reticulitermes flavipes (Rhinotermitidae) (Kollar, 1837) and Microcerotermes biroi (Termitidae) (Desneux, 1905). We confirmed that the secondary metabolite concentration decreased with wood age. We identified a core microbial consortium maintained in the gut of R. flavipes and M. biroi and found that its diversity and composition were not altered by the wood age. Therefore, the concentration of secondary metabolites had no effect on the termite gut microbiome. We also found that both termite feeding activities and wood age affect the wood microbiome. Whether the increasing relative abundance of microbes with termite activities is beneficial to the termites is unknown and remains to be investigated. IMPORTANCE Termites can feed on wood thanks to their association with their gut microbes. However, the current understanding of termites as holobiont is limited. To our knowledge, no studies comprehensively reveal the influence of wood age on the termite-associated microbial assemblage. The wood of many tree species contains high concentrations of plant toxins that can vary with their age and may influence microbes. Here, we studied the impact of Norway spruce wood of varying ages and terpene concentrations on the microbial communities associated with the termites Reticulitermes flavipes (Rhinotermitidae) and Microcerotermes biroi (Termitidae). We performed a bacterial 16S rRNA and fungal ITS2 metabarcoding study to reveal the microbial communities associated with R. flavipes and M. biroi and their impact on shaping the wood microbiome. We noted that a stable core microbiome in the termites was unaltered by the feeding substrate, while termite activities influenced the wood microbiome, suggesting that plant secondary metabolites have negligible effects on the termite gut microbiome. Hence, our study shed new insights into the termite-associated microbial assemblage under the influence of varying amounts of terpene content in wood and provides a groundwork for future investigations for developing symbiont-mediated termite control measures.
- MeSH
- Bacteria genetika MeSH
- dřevo * metabolismus MeSH
- ekosystém MeSH
- Isoptera * mikrobiologie MeSH
- RNA ribozomální 16S genetika metabolismus MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND: Termites primarily feed on lignocellulose or soil in association with specific gut microbes. The functioning of the termite gut microbiota is partly understood in a handful of wood-feeding pest species but remains largely unknown in other taxa. We intend to fill this gap and provide a global understanding of the functional evolution of termite gut microbiota. RESULTS: We sequenced the gut metagenomes of 145 samples representative of the termite diversity. We show that the prokaryotic fraction of the gut microbiota of all termites possesses similar genes for carbohydrate and nitrogen metabolisms, in proportions varying with termite phylogenetic position and diet. The presence of a conserved set of gut prokaryotic genes implies that essential nutritional functions were present in the ancestor of modern termites. Furthermore, the abundance of these genes largely correlated with the host phylogeny. Finally, we found that the adaptation to a diet of soil by some termite lineages was accompanied by a change in the stoichiometry of genes involved in important nutritional functions rather than by the acquisition of new genes and pathways. CONCLUSIONS: Our results reveal that the composition and function of termite gut prokaryotic communities have been remarkably conserved since termites first appeared ~ 150 million years ago. Therefore, the "world's smallest bioreactor" has been operating as a multipartite symbiosis composed of termites, archaea, bacteria, and cellulolytic flagellates since its inception. Video Abstract.
- MeSH
- fylogeneze MeSH
- Isoptera * MeSH
- metagenom MeSH
- půda MeSH
- střevní mikroflóra * genetika MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- audiovizuální média MeSH
- časopisecké články MeSH
- práce podpořená grantem MeSH
Animal interactions play an important role in understanding ecological processes. The nature and intensity of these interactions can shape the impacts of organisms on their environment. Because ants and termites, with their high biomass and range of ecological functions, have considerable effects on their environment, the interaction between them is important for ecosystem processes. Although the manner in which ants and termites interact is becoming increasingly well studied, there has been no synthesis to date of the available literature. Here we review and synthesise all existing literature on ant-termite interactions. We infer that ant predation on termites is the most important, most widespread, and most studied type of interaction. Predatory ant species can regulate termite populations and subsequently slow down the decomposition of wood, litter and soil organic matter. As a consequence they also affect plant growth and distribution, nutrient cycling and nutrient availability. Although some ant species are specialised termite predators, there is probably a high level of opportunistic predation by generalist ant species, and hence their impact on ecosystem processes that termites are known to provide varies at the species level. The most fruitful future research direction will be to evaluate the impact of ant-termite predation on broader ecosystem processes. To do this it will be necessary to quantify the efficacy both of particular ant species and of ant communities as a whole in regulating termite populations in different biomes. We envisage that this work will require a combination of methods, including DNA barcoding of ant gut contents along with field observations and exclusion experiments. Such a combined approach is necessary for assessing how this interaction influences entire ecosystems.
- MeSH
- DNA analýza MeSH
- ekologie MeSH
- Formicidae genetika fyziologie MeSH
- Isoptera genetika fyziologie MeSH
- predátorské chování MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Effective defense is a common characteristic of insect societies. Indeed, the occurrence of specialized defenders, soldiers, has been the first step toward eusociality in several independent lineages, including termites. Among the multitude of defensive strategies used by termite soldiers, defense by chemicals plays a crucial role. It has evolved with complexity in advanced isopteran lineages, whose soldiers are equipped with a unique defensive organ, the frontal gland. Besides direct defense against predators, competitors, and pathogens, the chemicals emitted by soldiers from the frontal gland are used as signals of alarm. In this study, we investigated the chemical composition of the defensive secretion produced by soldiers of the termite Termitogeton planus (Isoptera: Rhinotermitidae), from West Papua, and the effects of this secretion on the behavior of termite groups. Detailed two-dimensional gas chromatography/mass spectrometry analyses of the soldier defensive secretion revealed the presence of four linear and nine monoterpene hydrocarbons. Soldier head extracts, as well as synthetic mixtures of the monoterpenes found in these extracts, elicited alarm behavior in both soldiers and pseudergates. Our results suggest that the alarm is not triggered by a single monoterpene from the defensive blend, but by a multi-component signal combining quantitatively major and minor compounds.
- MeSH
- exokrinní žlázy chemie MeSH
- feromony chemie MeSH
- Isoptera chemie fyziologie MeSH
- monoterpeny chemie MeSH
- plynová chromatografie s hmotnostně spektrometrickou detekcí MeSH
- sociální chování MeSH
- uhlovodíky chemie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Trail-following behavior is a key to ecological success of termites, allowing them to orient themselves between the nesting and foraging sites. This behavior is controlled by specific trail-following pheromones produced by the abdominal sternal gland occurring in all termite species and developmental stages. Trail-following communication has been studied in a broad spectrum of species, but the "higher" termites (i.e. Termitidae) from the subfamily Syntermitinae remain surprisingly neglected. To fill this gap, we studied the trail-following pheromone in six genera and nine species of Syntermitinae. Our chemical and behavioral experiments showed that (3Z,6Z,8E)-dodeca-3,6,8-trien-1-ol is the single component of the pheromone of all the termite species studied, except for Silvestritermes euamignathus. This species produces both (3Z,6Z)-dodeca-3,6-dien-1-ol and neocembrene, but only (3Z,6Z)-dodeca-3,6-dien-1-ol elicits trail-following behavior. Our results indicate the importance of (3Z,6Z,8E)-dodeca-3,6,8-trien-1-ol, the most widespread communication compound in termites, but also the repeated switches to other common pheromones as exemplified by S. euamignathus.
- MeSH
- feromony metabolismus MeSH
- Isoptera fyziologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The gut microbiota of animals exert major effects on host biology [1]. Although horizontal transfer is generally considered the prevalent route for the acquisition of gut bacteria in mammals [2], some bacterial lineages have co-speciated with their hosts on timescales of several million years [3]. Termites harbor a complex gut microbiota, and their advanced social behavior provides the potential for long-term vertical symbiont transmission, and co-evolution of gut symbionts and host [4-6]. Despite clear evolutionary patterns in the gut microbiota of termites [7], a consensus on how microbial communities were assembled during termite diversification has yet to be reached. Although some studies have concluded that vertical transmission has played a major role [8, 9], others indicate that diet and gut microenvironment have been the primary determinants shaping microbial communities in termite guts [7, 10]. To address this issue, we examined the gut microbiota of 94 termite species, through 16S rRNA metabarcoding. We analyzed the phylogeny of 211 bacterial lineages obtained from termite guts, including their closest relatives from other environments, which were identified using BLAST. The results provided strong evidence for rampant horizontal transfer of gut bacteria between termite host lineages. Although the majority of termite-derived phylotypes formed large monophyletic groups, indicating high levels of niche specialization, numerous other clades were interspersed with bacterial lineages from the guts of other animals. Our results indicate that "mixed-mode" transmission, which combines colony-to-offspring vertical transmission with horizontal colony-to-colony transfer, has been the primary driving force shaping the gut microbiota of termites.
Termitidae comprises ∼80% of all termite species [1] that play dominant decomposer roles in tropical ecosystems [2, 3]. Two major events during termite evolution were the loss of cellulolytic gut protozoans in the ancestor of Termitidae and the subsequent gain in the termitid subfamily Macrotermitinae of fungal symbionts cultivated externally in "combs" constructed within the nest [4, 5]. How these symbiotic transitions occurred remains unresolved. Phylogenetic analyses of mitochondrial data previously suggested that Macrotermitinae is the earliest branching termitid lineage, followed soon after by Sphaerotermitinae [6], which cultivates bacterial symbionts on combs inside its nests [7]. This has led to the hypothesis that comb building was an important evolutionary step in the loss of gut protozoa in ancestral termitids [8]. We sequenced genomes and transcriptomes of 55 termite species and reconstructed phylogenetic trees from up to 4,065 orthologous genes of 68 species. We found strong support for a novel sister-group relationship between the bacterial comb-building Sphaerotermitinae and fungus comb-building Macrotermitinae. This key finding indicates that comb building is a derived trait within Termitidae and that the creation of a comb-like "external rumen" involving bacteria or fungi may not have driven the loss of protozoa from ancestral termitids, as previously hypothesized. Instead, associations with gut prokaryotic symbionts, combined with dietary shifts from wood to other plant-based substrates, may have played a more important role in this symbiotic transition. Our phylogenetic tree provides a platform for future studies of comparative termite evolution and the evolution of symbiosis in this taxon.
- MeSH
- biologická evoluce * MeSH
- fylogeneze MeSH
- hmyzí geny MeSH
- Isoptera genetika fyziologie MeSH
- symbióza * MeSH
- Termitomyces fyziologie MeSH
- transkriptom * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
True predators are characterised by capturing a number of prey items during their lifetime and by being generalists. Some true predators are facultative specialists, but very few species are stenophagous specialists that catch only a few closely related prey types. A monophagous true predator that would exploit a single prey species has not been discovered yet. Representatives of the spider family Ammoxenidae have been reported to have evolved to only catch termites. Here we tested the hypothesis that Ammoxenus amphalodes is a monophagous termite-eater capturing only Hodotermes mossambicus. We studied the trophic niche of A. amphalodes by means of molecular analysis of the gut contents using Next Generation Sequencing. We investigated their willingness to accept alternative prey and observed their specific predatory behaviour and prey capture efficiency. We found all of the 1.4 million sequences were H. mossambicus. In the laboratory A. amphalodes did not accept any other prey, including other termite species. The spiders attacked the lateral side of the thorax of termites and immobilised them within 1 min. The paralysis efficiency was independent of predator:prey size ratio. The results strongly indicate that A. amphalodes is a monophagous prey specialist, specifically adapted to feed on H. mossambicus.
- MeSH
- Isoptera genetika MeSH
- pavouci * genetika MeSH
- predátorské chování * MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Asexual queen succession (AQS), in which workers, soldiers and dispersing reproductives are produced sexually while numerous non-dispersing queens arise through thelytokous parthenogenesis, has recently been described in three species of lower termites of the genus Reticulitermes. Here, we show that AQS is not an oddity restricted to a single genus of lower termites, but a more widespread strategy occurring also in the most advanced termite group, the higher termites (Termitidae). We analysed the genetic structure in 10 colonies of the Neotropical higher termite Embiratermes neotenicus (Syntermitinae) using five newly developed polymorphic microsatellite loci. The colonies contained one primary king accompanied either by a single primary queen or by up to almost 200 neotenic queens. While the workers, the soldiers and most future dispersing reproductives were produced sexually, the non-dispersing neotenic queens originated through thelytokous parthenogenesis of the founding primary queen. Surprisingly, the mode of thelytoky observed in E. neotenicus is most probably automixis with central fusion, contrasting with the automixis with terminal fusion documented in Reticulitermes. The occurrence of AQS based on different mechanisms of ploidy restoration raises the hypothesis of an independent evolutionary origin of this unique reproductive strategy in individual lineages of lower and higher termites.
- MeSH
- biologická evoluce MeSH
- genotyp MeSH
- haplotypy MeSH
- hmyzí proteiny genetika metabolismus MeSH
- Isoptera genetika fyziologie MeSH
- molekulární sekvence - údaje MeSH
- partenogeneze * MeSH
- respirační komplex IV genetika metabolismus MeSH
- sekvenční analýza DNA MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH