Untreated L1 nematodes were incubated at 20°C and sampled at 0 h (black), 24 h (red), 48 h (green), and 72 h (blue). Upper panel, scatter-plot of optical density (log(EXT)) versus length (log(TOF)). Each point corresponds to an individual nematode. Lower panel, frequency distributions of log(EXT) versus numbers of nematodes. At 72 h, adult nematodes (high EXT, TOF) and their offspring (low EXT, TOF) were observed.