Subterranean Termites (Rhinotermitidae)

International audiencePhylogeny and classification The worldwide family Rhinotermitidae, or subterranean termites, comprises 15 genera and more than 300 species. They occupy an intermediate position between the so-called "lower" and "higher" termites and so are often referred to as "intermediate" termites (1). The Rhinotermitidae appears to be paraphyletic, with most researchers placing the clade with Coptotermes and Heterotermes as a sister group to the Termitidae. Some researchers regard the Serritermitidae as paraphyletic within the Rhinotermitidae-Termitidae clade, while others place it as a basal group of Rhinotermitidae, near other basal groups such as Rhinotermes, Prorhinotermes, and Schedorhinotermes. Other researchers feel that Serritermitidae lies at the crossroads of worker caste evolution in termites, between the lower termites and the Rhinotermitidae+Termitidae clade. The most basal rhinotermitid taxa, such as Rhinotermes, diverged from the other lower termites less than 100 MA ago. The latest literature reviews indicate that the well-known, more derived genera Reticulitermes and Coptotermes+Heterotermes consistently form two distinct clades in a monophyletic branch within the family (2). These three genera account for more than half the species in Rhinotermitidae (184 of 305) and are the best studied within the family. The native ranges of these three genera (Reticulitermes, Coptotermes and Heterotermes) are all broad but fairly distinct. Coptotermes and Heterotermes are largely pantropical, although Heterotermes does not occur in Africa. Coptotermes is absent from the Nearctic and Palearctic regions. Reticulitermes naturally occurs exclusively within temperate areas. The Coptotermes+Heterotermes clade and Reticulitermes separated about 60 MA, according to various researchers. However, based on historical biogeography, modern Reticulitermes species resulted from cladogenesis and are highly taxonomically distinct. More ancient fossils of the different genera have been found in Europe, and they geologically date back to around 38 MYA. In a recent molecular phylogeny for Coptotermes, created using the complete mitochondrial genome, the genus is composed of numerous poorly supported branches. This result is partly due to the high level of synonymy in the present nomenclature and does not help clearly differentiate the species. However, speciation patterns were relatively clear in Australia, where this clade is the best defined. Consequently, this genus should be revised to deal with the high levels of synonymy in some locations (3)

Origin and ecological selection of core and food-specific bacterial communities associated with meat and seafood spoilage

The microbial spoilage of meat and seafood products with short shelf lives is responsible for a significant amount of food waste. Food spoilage is a very heterogeneous process, involving the growth of various, poorly characterized bacterial communities. In this study, we conducted 16S ribosomal RNA gene pyrosequencing on 160 samples of fresh and spoiled foods to comparatively explore the bacterial communities associated with four meat products and four seafood products that are among the most consumed food items in Europe. We show that fresh products are contaminated in part by a microbiota similar to that found on the skin and in the gut of animals. However, this animal-derived microbiota was less prevalent and less abundant than a core microbiota, psychrotrophic in nature, mainly originated from the environment (water reservoirs). We clearly show that this core community found on meat and seafood products is the main reservoir of spoilage bacteria. We also show that storage conditions exert strong selective pressure on the initial microbiota: alpha diversity in fresh samples was 189 +/- 58 operational taxonomic units (OTUs) but dropped to 27 +/- 12 OTUs in spoiled samples. The OTU assemblage associated with spoilage was shaped by low storage temperatures, packaging and the nutritional value of the food matrix itself. These factors presumably act in tandem without any hierarchical pattern. Most notably, we were also able to identify putative new clades of dominant, previously undescribed bacteria occurring on spoiled seafood, a finding that emphasizes the importance of using culture-independent methods when studying food microbiota

Is the mind Bayesian? The case for agnosticism

Probability judgment, Subjective Bayesianism, Bayesian coherence, Probability revising, Probability updating, Linguistic pragmatics,