DCutFIG 10: Cuticle specializations of the dauer larva limits fluid and ion exchange between the body and the environment.

A. Alimentary system promotes intake and efflux of fluids and nutrients through the mouth and anus, respectively, in non-dauer stages, such as the L2. Transport through the alimentary system is halted in the dauer due to physical closure of the buccal opening and the anus.
B. Ion and fluid exchange through the excretory system is probably maintained in the dauer, as evidenced by the open excretory pore. The thickening of the dauer cuticle does not seem to restrict this opening, and might actually help it to resist forces that could cause collapse of the opening.
C. Thickening of the body wall cuticle prevents exchange of fluid and ions across the hypodermal route in the dauer. The sum of these changes may be significant for promoting dauer survival in desiccated environments.
Dark arrow indicates unrestricted flow; medium arrow indicates limited flow; crossed open arrow indicates blockage of flow. Double-headed arrow suggests two way flow is likely; single headed arrow indicates that one way flow is likely.

Click on picture for full resolution image.