Compartmentalization of microbial communities that inhabit the hindguts of millipedes. Issue 5 (September 2016)

• Record Type: Journal Article
• Authors: Nardi, James B.; Bee, Charles M.; Taylor, Steven J.
• Is Part Of: Arthropod structure & development. Volume 45:Issue 5(2016:Sep.)
• Page Start: 462
• Page End: 474
• Publication Date: 2016-09
• Subjects: Diplopoda -- Spirostreptida -- Julida -- Microbiome -- Hindgut -- Detritivore -- Ultrastructure -- Regional differentiation; Arthropoda -- Morphology -- Periodicals; Arthropoda -- Anatomy -- Periodicals; Arthropoda -- Cytology -- Periodicals; Arthropods -- growth & development -- Periodicals; 595
• DOI: 10.1016/j.asd.2016.08.007
• Languages: English
• ISSNs: 1467-8039

Abstract

Abstract: The gut lumen of the arthropod detritivore provides hospitable and multifaceted environments for diverse assemblages of microbes. Many microbes, including trichomycetes fungi, bacteria, and archaea establish stable, adherent communities on the cuticular surface secreted by the hindgut epithelium. Regional differences in the surface topography within the hindgut of a given millipede are reflected in differing and diverse microbial assemblages. The spirostreptid millipede Cambala speobia is a detritivore found on the floors of Texas caves. This millipede species has a very circumscribed distribution in North America and a diet confined to the limited litter that accumulates on floors of these caves while the common julid millipede Cylindroiulus caeruleocinctus, an introduced European species, feeds on the diverse litter found in organic soils throughout North America. In both millipedes, the gut lumina are inhabited along their entire lengths by microbes, with the highest microbial densities in the hindguts. The anterior third of the hindgut with its distinctive six-fold symmetry is lined by cuticle having fine polarized scales, and the posterior-most third is lined by smooth cuticle. Trichomycetes only inhabit the anterior third of the hindgut, and scattered patches of filamentous bacteria along with their smaller adherent microbes occupy the posterior third. The densest populations of microbes inhabit the central region of the hindgut. Over the cuticular surface of this hindgut region, uniformly distributed indentations mark possible channels for nutrient and water exchange between the hindgut lumen and host hemolymph. Films of microbes are adherent to the cuticle that lines the hindgut while those microbes in the remainder of the gut ( i.e., foregut + midgut) represent mostly unattached inhabitants. Graphical abstract: Highlights: Hindgut cuticles of millipedes are regionally differentiated along their anterior-posterior axes. Hindgut microbiomes show corresponding regional differentiation. Trichomycetes species of the genus Enterobryus inhabit only the anterior hindgut. Filamentous bacteria dominate the posterior half of hindgut. Regular discontinuities in hindgut cuticle offer possible channels for exchange between lumen and host's hemocoel.