Over-expression of four copies of brBRcore.Z4.hs using heat shock at 5 hours after ecdysis to the second instar causes a high rate of lethality at approximately 26 hours after the heat shock (the time of ecdysis from second to third instar). Double mouthhooks are seen in these dead larvae.
Animals carrying four copies of brBRcore.Z4.hs and heat shocked at 56 hours after puparium formation have essentially full length bristles that are unpigmented. The sockets of the macrochaetae are also not tanned.
In response to heatshock, ectopic dorsal appendage material is produced in the dorsal anterior region of the eggshell. 0-3 hours post heatshock about 5% of the eggs produced are abnormal, and 95% of eggs laid hatch. 3-5 post heatshock 43% of the eggs produced are abnormal, and only 4% of eggs laid hatch. From 5-24 hours post heatshock about 3/4 of eggs produced are abnormal, and 15% of eggs laid hatch. 24-48 hours post heatshock, about a 1/5 of eggs produced are abnormal, and 97% of eggs laid hatch. Viability is recovered to about 95% in 2 days after heatshock.
A 37oC heat shock causing expression of brBRcore.Z4.hs during the third larval instar or early prepupal stage results in lethality within a few hours of the heat shock. Heat shock induced expression of brBRcore.Z4.hs during late prepupal or pupal stages has no effect.