Water fleas require microbiota for survival, growth and reproduction

Abstract

Microbiota have diverse roles in the functioning of their hosts; experiments using model organisms have enabled investigations into these functions. In the model crustacean Daphnia, little knowledge exists about the effect of microbiota on host well being. We assessed the effect of microbiota on Daphnia magna by experimentally depriving animals of their microbiota and comparing their growth, survival and fecundity to that of their bacteria-bearing counterparts. We tested Daphnia coming from both lab-reared parthenogenetic eggs of a single genotype and from genetically diverse field-collected resting eggs. We showed that bacteria-free hosts are smaller, less fecund and have higher mortality than those with microbiota. We also manipulated the association by exposing bacteria-free Daphnia to a single bacterial strain of Aeromonas sp., and to laboratory environmental bacteria. These experiments further demonstrated that the Daphnia-microbiota system is amenable to manipulation under various experimental conditions. The results of this study have implications for studies of D. magna in ecotoxicology, ecology and environmental genomics.

Food availability affects the strength of mutualistic host–microbiota interactions in Daphnia magna

“…Our experiments clearly showed that removing the microbiota of D. magna had an overall negative effect on host growth, survival and reproduction. Although in this study we used a newly developed method to obtain germ-free Daphnia without the use of antibiotics, results from non-nutritionally stressed treatments are similar to what Sison-Mangus et al (2014) found with respect to growth, survival and reproduction. This confirms the generality of the mutualistic relationship between Daphnia and its microbiota.…”

“…showed that inoculating germ-free Daphnia with these bacteria had a positive effect on host fitness, although for Limnohabitans sp. this was found to be restricted to specific strains (Sison-Mangus et al, 2014;Peerakietkhajorn et al, 2015b). Interestingly, the dominant Aeromonas sp.…”

“…Notably, the β-proteobacterial genus Limnohabitans (Comamonadaceae) seems to be a major constituent of the Daphnia microbiota (Freese & Schink, 2011;Eckert & Pernthaler, 2014;. Sison-Mangus et al (2014) showed, by comparing bacteria-free Daphnia with conventional ones, that the relationship between D. magna and its microbiota is mutualistic, as removing the microbiota results in decreased growth, survival and reproduction of the host. It is, however, not known how this interaction is affected by variation in environmental conditions, such as food availability.…”

Changes in the bacterial community associated with hydra during reproduction

“…Studies in the past have shown that microbiota not only provides fitness benefit to the host but also plays a significant role in its reproduction [13]. To our knowledge, this is the first study reporting clear changes in microbial content during asexual reproduction and sexual maturity indicating microbial influence over a major life event.…”

Recirculating Aquaculture Systems Waste Water as a Medium for Increase of Phytoplankton and Zooplankton Biomass

“…An increase in the density of zooplankton monocultures during their cultivation on RAS waste water could represent the bacterial flora in this water, that serves an additional feed element for crustaceans and contributes to their reproduction [20].…”