Shaping the tripartite symbiosis: are termite microbiome functions directed by the environmentally acquired fungal cultivar?

Microbiome assembly critically impacts the ability of hosts to access beneficial symbiont functions. Fungus-farming termites have co-evolved with a fungal cultivar as a primary food source and complex gut microbiomes, which collectively perform complementary degradation of plant biomass. A large subset of the bacterial community residing within termite guts are inherited (vertically transmitted) from parental colonies, while the fungal symbiont is, in most termite species, acquired from the environment (horizontally transmitted).

Selective enrichment of founding reproductive microbiomes allows extensive vertical transmission in a fungus-farming termite.

Mutualistic coevolution can be mediated by vertical transmission of symbionts between host generations. Termites host complex gut bacterial communities with evolutionary histories indicative of mixed-mode transmission. Here, we document that vertical transmission of gut bacterial strains is congruent across parent to offspring colonies in four pedigrees of the fungus-farming termite .

Resistance and Vulnerability of Honeybee () Gut Bacteria to Commonly Used Pesticides.

Agricultural and apicultural practices expose honeybees to a range of pesticides that have the potential to negatively affect their physiology, neurobiology, and behavior. Accumulating evidence suggests that these effects extend to the honeybee gut microbiome, which serves important functions for honeybee health. Here we test the potential effects of the pesticides thiacloprid, acetamiprid, and oxalic acid on the gut microbiota of honeybees, first in direct inhibition assays and secondly in an caged bee experiment to test if exposure leads to gut microbiota community changes.

Female-biased sex allocation and lack of inbreeding avoidance in termites.

Sexually reproducing organisms face a strong selective pressure to find a mate and ensure reproduction. An important criterion during mate-selection is to avoid closely related individuals and subsequent potential fitness costs of resulting inbred offspring. Inbreeding avoidance can be active through kin recognition during mate choice, or passive through differential male and female-biased sex ratios, which effectively prevents sib-mating.

Ants Incur a Trade-Off between Phenotypic Development and Pathogen Susceptibility from Their Mutualistic Endosymbiont .

Various insects engage in microbial mutualisms in which the reciprocal benefits exceed the costs. Ants of the genus benefit from nutrient supplementation by their mutualistic endosymbiotic bacteria, , but suffer a cost in tolerating and regulating the symbiont. This cost suggests that the ants face secondary consequences such as susceptibility to pathogenic infection and transmission.