13. Microbiomes and cognition Flashcards
Animal microbiome
Microbial community (ex: bacteria, fungi, microbial eukaryotes) residing in or on certain body parts of an animal
Ex)
- skin and feather microbiome
- uropygial gland microbiome
- gut microbiome
- facial and bucal microbiome.
Why should we care about microbiomes?
- Detoxification
- Breakdown of macromolecules
- Synthesis of molecules
- Communication
- Immune related functions
- Brain development and cognition
Gave rise to a new field of research: Hologenome (all the genes from the host and the microbes associated with the host)
- To fully understand the ecology and evolution of a macroorganism, we need to look at their interactions with microbial symbionts
Which factors affect the avian gut microbiomes?
Genetic and physiological factors (genes passed, down, physiology of gut, sex)
Ecological and behavioral factors (diet, social interactions, inter/intra interactions, migration)
Environmental factors (location, industrilisation, host-parasite associations)
How do microbial symbionts impact animal behavior?
1) Can provide plasticity
2) Improve cognition
3) Manage stress
4) Trans-generational transfer of information
Microbes can facilitate dietary behaviors of animals
Great tits have different diets in summer and winter
In an experiment, they were given different diets, which should in theory give them different microbiomes. Then the diets were changed back to their original diet.
Results showed that the microbial commmunities changed compared to the diet they were given. When they were given their original diet, the community could revert back to the original community.
Diet influence the cognition of birds
Great tits were given a problem and were able to solve some of them. Two groups (one insect diet and one seed diet) were given the problems, and it was shown that the insect diet group lost their ability to solve the problems.
Microbes can manipulate the diet selection behaviors (carnivore, omnivore, herbivore)
Three mice types (Carnivores, Omnivores and Herbivores) were sampled and their gut microbiomes were transferred to new mice. They were then observed to see how it determined their diet selection.
They were found that the transfer worked…
Microbes can impact memory
They had conventional bees, conventional bees treated with tetracycline (antibiotics) and germ-free bees (no microbiome)
They did a training set where they were given a smell (nonanol), and if they chose the smell, they were given a reward.
They were then given two smells (nanol and hexanal) and it was observed where they would go (which smell they would choose). We would expect the one with learned reward.
Conventional bees remembered the right scent ca 50% of the time.
The treated bees had a worse memory
The germ free bees could not remember anything from the training session
Can influence social behaviors (strong effect on brood rearing behavior)
Bees given antiobiotic treatment to change communities of microbiomes.
If the brood was treated with antibiotics, they lost the ability to rear brood (affected brood rearing behavior). In the recovery period, no improvement was shown.
Symbiotic bacteria can produce volatile odorants facilitating animal host communication
An example is the preen glands of dark-eyed Juncos or scent glands of Hyena
The bacterial communities in these glands are responsible for the olfactory communication
Gut microbiomes can facilitate the recognition of nest mates
Bees from different colonies and with different microbiota were treated with antibiotics, and it was found that if you had been treated with acinetobacter, all three colonies would accept you. If you had been treated with the second bacteria (L. quercina), it lowered your acceptance rate.
Social interactions will also impact host associated microbiomes
Individuals who interact a lot have more similar microbiomes
And individuals with more similar microbiomes will interact more
What can influence the microbial symbionts?
Social interactions can impact host associated microbiomes
Social interactions can also shape the host microbe associations
Social interactions (and shared environment) can help recover microbiomes
Summary
Gut microbiomes play a multitude of critical functions for their animal hosts
These microbial communities can provide plasticity for their hosts to respond to changes in the environment
Microbial symbionts can influence the animal behaviors, cognition and communication and also can be impacted by the social interactions
Understanding how hosts and their microbial symbionts interact are important to fully understand animal ecology and behavior
What can microbiomes do? Overview
Facilitate dietary behaviors in animals (great tits)
Manipulate diet selection behaviors (mice)
Impact memories (bees)
Influence social behavior- especially brood rearing behavior
Symbiotic bacterium produce volatile odorants for host communication (hyenas)
Facilitates recognition in nest mates (bees)
