Work group 06: Symbionts and phenotypic plasticity
1. Mutualistic interactions with nematodes. They are required for nematode fertility and
survival, which makes it interesting to investigate what underlying mechanisms cause
this necessity. Additionally, B. malayi are able to infect humans and understanding
the interactions between the nematode and Wolbachia could lead to advancements in
drug therapy.
2. Wolbachia is capable of surviving and thriving on its own; some species are freeliving organisms, they are not dependent on other species or organisms like the
nematode. With our cells and the mitochondria, this is definitely not the case.
Different species theories exist, therefore the boundary between two distinct species
and one species is not always clear.
3. – B. malayi has an MTOC in the unfertilized mature oocyte, whereas C. elegans
derives its MTOC paternally.
- In C. elegans, A-P polarity is established through the SEP, whereas in B. malayi
it is established partially through Wolbachia.
- C. elegans legt eitjes, B. malayi niet.
4. The depletion of Wolbachia may act in a non-cell autonomous way, where B. malayi’s
metabolism as well as its nutrient provision is affected. This may lead to a disturbed
development. Distinguish between Wolbachia in the eggs and tissue.
5. I would not consider the interaction mutualistic, as mutualistic interactions either
suggest co-dependence or a voluntary interaction. The nematode is entirely
dependent on the bacteria, where the bacteria is even capable of creating a
reproduction barrier.
6. C. elegans is unable to establish A-P polarity when these proteins are silenced. In B.
malayi, the Wolbachia is unable to segregate asymmetrically, leading to an inability to
establish the A-P polarity.
7. They supposedly first use kinesin and subsequently dynein motor proteins and the
microtubule network to establish the posterior localization.
8. They show two distinct phenotypes when challenged with a changing environment.
Leading to useful information in eco-evo-devo systems. “Indeed, spadefoots respond
to numerous environmental factors that influence fitness.”
9. Plasticity as antecedent for novelty. Developmental switches  Mutations in
developmental regulations. Reciprocal accommodation  10, 11, 12. Niche
construction and the consequently changes in fitness.
10. Looking for intermediate forms. Use phylogenies to infer whether or not these novel
adaptations could have occurred in ancestral taxa. Selection studies on variation
exposed under novel environmental regimes.
11. The co-existence with the constitutively carnivore morph of S. bombifrons would lead
to a greater competition between these two species if the carnivore morph in S,
multiplicata would also be expressed. The canalization of S. multiplicata regardless its
plasticity, generating less competition, could therefore be considered as character
displacement.
12. Invading group of bombifrons under sympatry is able to canalize. The differences in
invasion could lead to difference in canalization.
13. Maternal effects are able to facilitate overervingen  Feedback loop. Maternal effects
can influence great numbers of offspring. Maternal effects can initiate robust
evolution, where the trend …. . The genetic diversity could be combined with
maternal effects, leading to greater variety and adaptivity.
14. Competitive environmental.
15. The latter. Co-option. One system used to induce a lot of other factors.