Bacterial communities associated with animals show complex spatial and temporal variation. The main driving forces behind this variation are still to be deciphered. Differences in microbiome composition could be caused by stochastic changes, such as random gain and loss of microbiome components, as well as deterministic factors, such as variation in temperature (or other abiotic factors), diet, or the availability of microbes...

Changing ecological factors pose a challenge to many organisms. Global changes and the associated environmental changes have major impacts on marine organisms and threaten the biodiversity of marine ecosystems. It has been shown in previous experimental studies that ocean acidification caused by anthropogenic CO 2 release into the atmosphere and subsequent dissolution in seawater will have a significant impact on various marin...

Marine sponges are known for their complex and stable microbiomes. However, the lack of a gnotobiotic sponge‐model and experimental methods to manipulate both the host and the microbial symbionts currently limit our mechanistic understanding of sponge‐microbial symbioses. We have used the North Atlantic sponge species Halichondria panicea to evaluate the use of antibiotics to generate gnotobiotic sponges. We further asked whet...

Summary The establishment of host–bacterial colonization during development is a fundamental process influencing the fitness of many organisms, but the factors controlling community membership and influencing the establishment of the microbial ecosystem during development are poorly understood. The starlet sea anemone N ematostella vectensis serves as a cnidarian model organism due to the availability of laboratory cultures an...

Summary Microbes have profound influence on the biology of host tissue. Imbalances in host–microbe interaction underlie many human diseases. Little, however, is known about how epithelial homeostasis affects associated microbial community structure. In Hydra , the epithelium actively shapes its microbial community indicating distinct selective pressures imposed on the epithelium. Here, using a mutant strain of Hydra magnipapil...

Summary Mycoplasms are known as pathogens of economic and medical interest in plants, animals and man. Here, we show a positive correlation between the presence of Mycoplasma ‐like symbionts in their isopod hosts and survivorship on low‐quality food. Most isopods that survived feeding on a cellulose‐based low‐quality diet for 90 days harboured ‘ Candidatus Hepatoplasma’ in their midgut glands, while those that died within 90 d...