Flies in which kluhs.PY is expressed in a burst using heat shock at 23, 24, 25 or 26 hours after puparium formation have a reduction in the number of cells surrounding each ommatidial core.
Ectopic expression of kluhs.PY by heat shock reduces the number of mature RP2 neurons in late embryos. Heat shock treatment at stage 10 results in the maximal loss of mature RP2 neurons.