AUTHOR=Hubert Jan , Nesvorna Marta , Sopko Bruno , Smrz Jaroslav , Klimov Pavel , Erban Tomas 

TITLE=Two Populations of Mites (Tyrophagus putrescentiae) Differ in Response to Feeding on Feces-Containing Diets

JOURNAL=Frontiers in Microbiology

VOLUME=9

YEAR=2018

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2018.02590

DOI=10.3389/fmicb.2018.02590

ISSN=1664-302X

ABSTRACT=<p><bold>Background:</bold><italic>Tyrophagus putrescentiae</italic> is a ubiquitous mite species in soil, stored products and house dust and infests food and causes allergies in people. <italic>T. putrescentiae</italic> populations harbor different bacterial communities, including intracellular symbionts and gut bacteria. The spread of microorganisms via the fecal pellets of <italic>T. putrescentiae</italic> is a possibility that has not been studied in detail but may be an important means by which gut bacteria colonize subsequent generations of mites. Feces in soil may be a vector for the spread of microorganisms.</p><p><bold>Methods:</bold> Extracts from used mite culture medium (i.e., residual food, mite feces, and dead mite bodies) were used as a source of feces-inhabiting microorganisms as food for the mites. Two <italic>T. putrescentiae</italic> populations (L and P) were used for experiments, and they hosted the intracellular bacteria <italic>Cardinium</italic> and <italic>Wolbachia</italic>, respectively. The effects of the fecal fraction on respiration in a mite microcosm, mite nutrient contents, population growth and microbiome composition were evaluated.</p><p><bold>Results:</bold> Feces from the P population comprised more than 90% <italic>Bartonella</italic>-like sequences. Feces from the L population feces hosted <italic>Staphylococcus, Virgibacillus, Brevibacterium, Enterobacteriaceae</italic>, and <italic>Bacillus</italic>. The mites from the P population, but not the L population, exhibited increased bacterial respiration in the microcosms in comparison to no-mite controls. Both L- and P-feces extracts had an inhibitory effect on the respiration of the microcosms, indicating antagonistic interactions within feces-associated bacteria. The mite microbiomes were resistant to the acquisition of new bacterial species from the feces, but their bacterial profiles were affected. Feeding of P mites on P-feces-enriched diets resulted in an increase in <italic>Bartonella</italic> abundance from 6 to 20% of the total bacterial sequences and a decrease in <italic>Bacillus</italic> abundance. The population growth was fivefold accelerated on P-feces extracts in comparison to the control.</p><p><bold>Conclusion:</bold> The mite microbiome, to a certain extent, resists the acquisition of new bacteria when mites are fed on feces of the same species. However, a <italic>Bartonella-</italic>like bacteria-feces-enriched diet seems to be beneficial for mite populations with symbiotic <italic>Bartonella</italic>-like bacteria. Coprophagy on the feces of its own population may be a mechanism of bacterial acquisition in <italic>T. putrescentiae</italic>.</p>