the environment that this nematode could be using for exiting the dauer stage. This was statistically related with a high degree of significance indicating that the alae may specifically function as a receptor site. In the case of H. contortus the dauer nematode can remain in the gastric epithelium for months and until the right signals indicating conditions outside the host are favorable for egg survival, it will then trigger resumption of development. During the dauer stage the mouth and anal openings are sealed and neural receptors around the head retracted. The alae is more pronounced than at any other stage and remains exposed to the external environment. Triggers for exiting the dauer state may be determined by the concentration of target molecules around the nematode. In order to measure concentrations accurately, a very large receptor area is necessary, hence a structure such as the alae may be required. Postulated function The alae appears to be a neural receptor responsive to just a handful of molecules particular to each species of nematode. Up to half a dozen types of receptors may be present at any one time on the alae and each type would be very numerous. The target molecules in the environment that stimulate each type of receptor may then be measured for their concentration and a threshold reached before an action is instigated. These actions may instigate entry into the dauer state (L1 alae), exiting of the dauer state (pheromone and or presence of an indicator for food availability), for sexual reproduction where the area around the vulva and gonads of the female and male use this family of receptors (RAM-5) where the nematode is likely to identify that reproductive organs are in contact. And quite probably there are some other functions that we have not yet been found. References Nematode anatomy