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N2 development times at different temperatures


N2 development times at different temperatures

by Michael Koelle


Determined empirically; times in hours are given from the first division of the zygote.

 

15°

20°

25°
eggs laid

2

1

7
hatch

22

13

9
L1 molt

49

29

21
L2 molt

64.5

38

27
L3 molt

80

47

33
L4 molt

98.5

58

41

For staging later animals: L4's can be easily recognized and staged to within a few hours of development. By picking L4's and then aging them, a fairly synchronous population of adults of known age can be obtained; this is especially useful for behavioural assays, the results of which may depend on age.

L4 hermaphordites are recognized by a white crescent shape at the location of the developing vulva, about 2/3 of the way towards the posterior of the animal, on it's "side" as it lies on the plate. This stands out in contrast to the darker yellow gray of the surrounding body. Over time, the L4's get fatter relative to their length, a dark spot appears in the middle of the white crescent, and finally the white crescent collapses prior to the L4 molt. Thus substages of L4 are recognizable.

L4 males are recognized by a tail that is just beginning to acquire a spade shape, but has not achieved the well defined sharply cornered spade-tail of the adult. Since young males are better at mating, it is best to set up matings with L4 males.