Figure 2.

Time course of the physiological, behavioral, and endocrine events that occur at ecdysis from the second to the third larval instar in wild-type larvae. A, Open bars, Period between DVP stage and onset of pre-ecdysis (gray bar). Pre-ecdysis terminated with the onset of “biting” behavior (Bite), which was then followed by the initiation of ecdysis behavior (black bar). Additional events that occurred during the progression to ecdysis are also indicated. They were as follows: the collapse of the second instar trachea (Collapse); the entry of air into the third instar trachea (Air); and locomotion stopping (Stop). B, Immunoreactivity to ETH (open bars) and cGMP (filled circles) in Inka cells and to EH (open triangles) and CCAP-IR (C) in the CNS, during the progression to ecdysis. The abscissa indicates the times at which larvae were examined relative to the events shown in A. In A, records from individual larvae were aligned relative to the time of air filling (Air) (average ± SEM time for each event calculated). The SEM is indicated by error bars beneath the record; because Air corresponded to time 0 for all of the records, it had no associated error. Values in B and C are average ± SEM immunoreactivity scores (n > 8 for each data point). With the exception of EH, the quantitation of immunoreactivity was categorical; the SEMs associated with ETH- and cGMP-IR are only shown to illustrate the variance of the data and were not used to infer statistical significance. nd, Not determined.