Table 1.

Dauer characteristics in P. pacificus. Most of these characteristics have been described previously (see references); differences found in C. elegans are shown in bold.

category	dauer characteristic	references
(a) morphology	thin and dense body; axial ratio for P. pacificus is 16:1 (length:width), for C. elegans it is 30:1.	[35–37]
	remodelled foregut pharynx	[38]
	dark sealed intestine, generally darker than corresponding J3 stage, or L2 for C. elegans	[35–37]
	closed mouth and constricted pharynx	[35–37,39]
	gonadal arrest	[35–37]
	strengthened, specialized cuticle with lateral ridges: peripheral ridges become more pronounced in P. pacificus, whereas conspicuous lateral alae become visible for C. elegans	[35–37,39]
	fat bodies in intestinal and hypodermal cells	[40]
	remodelled neurons in C. elegans; has not been characterized for P. pacificus	[41]
(b) physiology	developmental arrest	[42]
	increase in lifespan reduced metabolic activity and dependence on internal energy storage; work in progress for P. pacificus (M. Mayer, A. Ogawa & R. Sommer, 2009, personal communication)	[37,43,44]
	resistance to environmental stress heat, cold, desiccation, oxidative stress and detergents such as SDS in C. elegans; has not been tested for P. pacificus	[35–37,43–46]
(c) behaviour	lethargic needle-like pose with reduced activity	[35–37]
	nictation	[35]