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UPSC Prelims 1995 · Environment · Species Watch
Most of the desert plants bloom during night time because
- (a) their blooming is controlled by low temperature
- (b) they are sensitive to the phases of moon
- (c) the desert insects eat away flowers during daytime
- (d) the desert insects are active during night time
Show the answer and explanation
Answer: (d) the desert insects are active during night time
Desert pollinators (moths, bats) are active at night to avoid the heat, so flowers open then.
The idea
A flower opens when its pollinator is on the move. In a desert the day is too hot and dry for most insects, so moths and bats feed at night. Desert flowers match this by opening after dark.
Night-blooming flower: white or pale, strong scent → moths and bats find it in the dark → Day-blooming flower: bright colour → bees, butterflies and birds find it by sight
Why the others are wrong
(a) Cooler nights help, but blooming is timed to pollinators.
(c) Insects don’t eat flowers away by day.
The trap
(a) sounds scientific. The driver is the pollinator’s timetable.
Also know
Opening at night also saves water, since a flower loses less moisture in cool air.
🔒 Desert flowers bloom at night → moths and bats pollinate.