mldDTS3-1/+ heterozygote adults reared at 18[o]C during development and transferred to 29[o]C after eclosion show more rapid ethanol-induced sedation compared to control. No effect on sedation sensitivity is observed in animals reared continuously at 18[o]C.
In contrast to wild-type controls, heterozygous males do not show courtship suppression 30 minutes after a 1 hour conditioning in a courtship conditioning assay. This defect is suppressed if the males are fed 0.1mM 20-hydroxy-ecdysone for 10 minutes immediately prior to conditioning.
mldDTS3-1/+ is lethal during development at 29[o]C but adults are able to develop at 25[o]C.
mldDTS3-1/+ females raised at 25[o]C sleep less than controls over a 24 hour period (12 hours light and 12 hours dark). Daytime sleep is reduced most significantly with a 65% reduction compared to 16% in nighttime sleep. The sleep pattern of mldDTS3-1 mutants is similar to control flies for the first hour after the shift from light to dark.
The average length of bouts of sleep when mldDTS3-1/+ female flies are exposed to 12 hours of light and 12 hours of dark is reduced compared with controls. The greatest difference in maximum sleep bout length is seen in the first 8 daytime hours and the last four nighttime hours. No difference from controls is seen between hours 8 and 20.
Average wake bout duration during the daytime in mldDTS3-1/+ females is approximately 5 times longer than in control flies. No difference in wake bout duration is seen at night. Waking activity is increased compared to controls during the day but not at night.
mldDTS3-1/+ females regain less sleep following 12 hours of sleep deprivation. The increase in average sleep bout duration seen in controls following sleep deprivation does not occur in these mutants.
l(3)DTS31/+ results in developmental lethality at 29[o]C. At 25[o]C heterozygous males are viable, but trained animals show defective long-term memory in courtship behaviour assays. Defects in long-term memory are rescued by feeding heterozygous males the steroid hormone 20-hydroxyecdysone (20E) during the training period.
Heterozygous female adults show a temperature dependent increase in longevity. At 29oC they show an increase of mean life-span of 42%. Males do not show a significant increase in life span at any of the temperatures tested. Heterozygous females show an increase in resistance to dry starvation; flies exposed to 29oC show an increase in mean survival time at 25oC of about 33% compared to controls. Males show no changes in resistance compared to controls. The increase in longevity seen in heterozygous females at 29oC is decreased in a dose-sensitive manner by feeding the flies 20-OH-ecdysone. The increased survival under dry starvation conditions of heterozygous females is also reversed by feeding the flies 20-OH-ecdysone.
Mutant larvae develop relatively normally at the restrictive temperature of 29oC, but are unable to pupariate.
After 5 days at the restrictive temperature (29.5oC), heterozygous females have an ecdysteroid titre approximately half that of wild-type flies. Egg hatchability decreases with the exposure time of the heterozygous mothers to 29.5oC until after 7-8 days no eggs hatched. This sterility is reversible; heterozygous females shifted to 22oC resume production of some hatchable eggs after 2 days. The lethal phase of the progeny of heterozygous females depends on the length of time the females are kept at the sublethal temperature of 27oC, indicating that the mutation shows a maternal effect. Yolk polypeptide mRNA and protein levels are not reduced in heterozygous females kept at the restrictive temperature.
Heterozygotes die as third instar larvae at 29oC. The third instar larval stage may be prolonged for 14 days before death occurs. The temperature-sensitive period is during the second to third instar stage.
Lethal phase is during the third larval instar stage at 29oC. Heterozygous larvae raised at 29oC are arrested at the third larval instar stage for up to two weeks. They have grossly hypertrophied ring glands due to the growth of the prothoracic gland cells. The nuclei possess polytene chromosomes which are as large as those of salivary gland nuclei; their banding pattern is similar but not identical to that of salivary gland polytene chromosomes, but the puffing patterns are quite different. Salivary gland chromosomes also hypertrophy and lack the normal ecdysone-induced puffs.