Mouth form polymorphism

From Wikionchus

Pristionchus species, like other Diplogastrina members show a morphological dimorphism in the buccal cavity between eury- and stenostomatous worms. Stenostomatous buccal cavity is narrow whereas eurystomatous worms have a broad buccal cavity. Among the different tooth-like structures present in the buccal cavity, stenostomatous worms lack the tooth of the right subventral side, and the dorsal tooth is not claw-like as in eurystomatous worms. The variation in stomatal morphology in Diplogastrina is thought to be related to different feeding habits. (Fürst von Lieven & Sudhaus, 2000)

The aims of this project are to:

- understand the genetic basis of these alternative phenotypes: is it a genetic polymorphism or phenotypic plasticity underlying the presence of the two morphologies?

- find how are these different morphs molecularly executed during development.

- understand the relationship between the maintenance of the alternative mouth phenotypes and the ecology of these species, as these free living nematodes who have a very close association with scarab beetles.

- understand if adaptive evolution played a role in the development of these morphologies.

We aim to understand the general trends in the evolution of nematodes (in this case from free-living to insect parasitic ecology), and the role of developmental plasticity and modularity in evolution.