Malpighian tubules in homozygous embryos are shorter than wild type, posterior tubules are more strongly affected than the anterior. Reduction in size of the tubules is due to reduction in cell number, not cell death.
Homozygotes show a weak Egfr phenotype: the cuticle is more intact than in stronger Egfr alleles, but shows reductions in the ventral plate and H piece of the anterior head skeleton. There are variable reductions in the number and size of ventral setae and occasional ventral or dorsal midline defects. Many embryos fail to complete germ band retraction.
Weak 'flb' phenotype when homozygous and hemizygous. Embryos produced from heteroallelic combination with Egfrt1 have a severe ventralised phenotype, reduction in size of their dorsal appendage. Individuals are fully viable over the pupal lethals Egfrtop-CA and Egfrtop-EC20 and show a reduction in viability over Egfrtop-EB.