391 research outputs found
Schievitermes globicornis, a new genus and species of Termitinae (Blattodea, Termitidae) from French Guiana
Asymmetrical snapping mandibles have evolved several times in termites. In the Neotropics, asymmetrical snapping mandibles are found in soldiers of four genera: Neocapritermes, Planicapritermes, Cornicapritermes and Dihoplotermes. Here, I describe Schievitermes globicornis, new genus and species, from French Guiana. This genus is characterized by an absence of a frontal prominence and slightly asymmetrical mandibles in the soldier caste. The morphology and anatomy of the worker reveal a wood-based diet, and suggest that Schievitermes, Planicapritermes and Neocapritermes constitute a monophyletic group, which is consistent with mtDNA data
Not Only Soldiers Have Weapons: Evolution of the Frontal Gland in Imagoes of the Termite Families Rhinotermitidae and Serritermitidae
BACKGROUND: The frontal gland is a unique adaptation of advanced termite families. It has been intensively studied in soldiers with respect to its anatomy and chemistry, with numerous novel compounds being discovered within the tremendous richness of identified products. At the same time, the presence of the frontal gland in non-soldier castes received only negligible attention in the past. PRINCIPAL FINDINGS: Here, we report on the development of the frontal gland in alate imagoes of 10 genera and 13 species of Rhinotermitidae and Serritermitidae, in order to shed light on the evolution and function of this gland in imagoes. All investigated species possess a frontal gland. In most cases, it is well-developed and equipped with a sac-like reservoir, located in the postero-dorsal part of cranium, but reaching as far as the seventh abdominal segment in some Rhinotermitinae. The only exception is the genus Psammotermes, in which the gland is very small and devoid of the reservoir. CONCLUSIONS: Our direct observations and comparisons with soldiers suggest a defensive role of the gland in imagoes of all studied species. This functional analogy, along with the anatomic homology between the frontal gland in soldiers and imagoes, make it likely that the gland appeared once during the early evolution of rhinotermitid ancestors, and remained as a defensive organ of prime importance in both, soldiers and imagoes
Neoisoptera repeatedly colonised Madagascar after the Middle Miocene climatic optimum
Madagascar is home to many endemic plant and animal species owing to its ancient isolation from other landmasses. This unique fauna includes several lineages of termites, a group of insects known for their key role in organic matter decomposition in many terrestrial ecosystems. How and when termites colonised Madagascar remains unknown. In this study, we used 601 mitochondrial genomes, 93 of which were generated from Malagasy samples, to infer the global historical biogeography of Neoisoptera, a lineage containing more than 80% of described termite species. Our results indicate that Neoisoptera colonised Madagascar between 7 and 10 times independently during the Miocene, between 8.4 and 16.6 Ma (95% HPD: 6.1–19.9 Ma). This timing matches that of the colonization of Australia by Neoisoptera. Furthermore, the taxonomic composition of the Neoisopteran fauna of Madagascar and Australia are strikingly similar, with Madagascar harbouring an additional two lineages absent from Australia. Therefore, akin to Australia, Neoisoptera colonised Madagascar during the global expansion of grasslands, possibly helped by the ecological opportunities arising from the spread of this new biome.journal articl
A holobiont approach towards polysaccharide degradation by the highly compartmentalised gut system of the soil-feeding higher termite Labiotermes labralis.
peer reviewed[en] BACKGROUND: Termites are among the most successful insects on Earth and can feed on a broad range of organic matter at various stages of decomposition. The termite gut system is often referred to as a micro-reactor and is a complex structure consisting of several components. It includes the host, its gut microbiome and fungal gardens, in the case of fungi-growing higher termites. The digestive tract of soil-feeding higher termites is characterised by radial and axial gradients of physicochemical parameters (e.g. pH, O2 and H2 partial pressure), and also differs in the density and structure of residing microbial communities. Although soil-feeding termites account for 60% of the known termite species, their biomass degradation strategies are far less known compared to their wood-feeding counterparts.
RESULTS: In this work, we applied an integrative multi-omics approach for the first time at the holobiont level to study the highly compartmentalised gut system of the soil-feeding higher termite Labiotermes labralis. We relied on 16S rRNA gene community profiling, metagenomics and (meta)transcriptomics to uncover the distribution of functional roles, in particular those related to carbohydrate hydrolysis, across different gut compartments and among the members of the bacterial community and the host itself. We showed that the Labiotermes gut was dominated by members of the Firmicutes phylum, whose abundance gradually decreased towards the posterior segments of the hindgut, in favour of Bacteroidetes, Proteobacteria and Verrucomicrobia. Contrary to expectations, we observed that L. labralis gut microbes expressed a high diversity of carbohydrate active enzymes involved in cellulose and hemicelluloses degradation, making the soil-feeding termite gut a unique reservoir of lignocellulolytic enzymes with considerable biotechnological potential. We also evidenced that the host cellulases have different phylogenetic origins and structures, which is possibly translated into their different specificities towards cellulose. From an ecological perspective, we could speculate that the capacity to feed on distinct polymorphs of cellulose retained in soil might have enabled this termite species to widely colonise the different habitats of the Amazon basin.
CONCLUSIONS: Our study provides interesting insights into the distribution of the hydrolytic potential of the highly compartmentalised higher termite gut. The large number of expressed enzymes targeting the different lignocellulose components make the Labiotermes worker gut a relevant lignocellulose-valorising model to mimic by biomass conversion industries.Explor‑ ing the higher termite lignocellulolytic system to optimise the conversion of biomass into energy and useful platform molecule
Evolution of Termite Symbiosis Informed by Transcriptome-Based Phylogenies
Termitidae comprises approximately 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
Arthropod distribution in a tropical rainforest: tackling a four dimensional puzzle
Quantifying the spatio-temporal distribution of arthropods in tropical rainforests represents
a first step towards scrutinizing the global distribution of biodiversity on Earth. To date moststudies have focused on narrow taxonomic groups or lack a design that allows partitioning
of the components of diversity. Here, we consider an exceptionally large dataset (113,952
individuals representing 5,858 species), obtained from the San Lorenzo forest in Panama,
where the phylogenetic breadth of arthropod taxa was surveyed using 14 protocols targeting
the soil, litter, understory, lower and upper canopy habitats, replicated across seasons
in 2003 and 2004. This dataset is used to explore the relative influence of horizontal, vertical
and seasonal drivers of arthropod distribution in this forest. We considered arthropod abundance,
observed and estimated species richness, additive decomposition of species richness,
multiplicative partitioning of species diversity, variation in species composition,
species turnover and guild structure as components of diversity. At the scale of our study
(2km of distance, 40m in height and 400 days), the effects related to the vertical and seasonal
dimensions were most important. Most adult arthropods were collected from the soil/
litter or the upper canopy and species richness was highest in the canopy. We compared
the distribution of arthropods and trees within our study system. Effects related to the seasonal
dimension were stronger for arthropods than for trees. We conclude that: (1) models
of beta diversity developed for tropical trees are unlikely to be applicable to tropical arthropods;
(2) it is imperative that estimates of global biodiversity derived from mass collecting of
arthropods in tropical rainforests embrace the strong vertical and seasonal partitioning
observed here; and (3) given the high species turnover observed between seasons, global
climate change may have severe consequences for rainforest arthropods
SISTEM PENDUKUNG KEPUTUSAN POLA OLAHRAGA BERDASARKAN HASIL YANG INGIN DICAPAI MENGGUNAKAN FUZZY DATABASE MODEL TAHANI
Pada saat ini, perkembangan di dunia kesehatan telah berkembang secara cepat sehingga mendorong para ahli untuk merancang sebuah teknologi yang dapat mengambil keputusan didalam bidang kesehatan. Kesehatan merupakan hal sangat mahal dan sangat penting bagi keberlangsungan hidup manusia. Untuk mendapatkan tubuh yang sehat tentunya di butuhkan olahraga yang teratur. Olahraga dilakukan juga harus dengan porsi yang dibutuhkan oleh tubuh. Ketidaktahuan akan porsi olahraga yang dibutuhkan oleh tubuh manusia ini yang menjadi masalah bagi kebanyakan orang. Penelitian ini menggunakan metode studi literature dalam pengumpulan data serta fuzzy database model tahani. Pengembangan sistemnya menggunakan metode waterfall. Pemodelan analisis dan desain menggunakan bahasa pemograman PHP dan database server MySQL. Metode pengujian menggunakan pengujian white box. Hasil penelitian ini adalah sebuah sistem pendukung keputusan pola olahraga berbasis website yang dapat memudahkan pengguna dalam menentukan pola olahraga yang cocok dilakukan sesuai data kriteria yaitu umur, berat badan dan tinggi badan
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