UPSC Express

A recent study shows that flowering plants have evolved to produce a ‘Blue Halo’ from there petals. Which of the following statements is correct regarding the Blue Halo?

a       It is invisible to humans but lure pollinating bees
b       It repels the harmful insects by triggering their panic centers.
c       It helps in repelling the harmful UV radiations coming from the sun.
d       None of the above
Explanation:

Solution (a)

Blue Halo

Hundreds of flower species have evolved the ability to project ethereal halos of blue light invisible to humans in order to lure pollinating bees.
In laboratory experiments, bumblebees were drawn to synthetic flowers designed to generate the same kind of ultraviolent rings.
The effect occurs in the ultraviolent part of the optical spectrum that we cannot see, but bees can.
Previous studies have shown that bees in search of nectar-giving plants are attracted to odours, but take most of their cues from colours and petal shapes. Bees are especially sensitive to the band of colours on the light spectrum where blue graduates into ultraviolent.
Process

Many flowers lack the genetic and biochemical capability to manipulate pigment chemistry into the blue-to-ultraviolent spectrum.
So arranging the molecules in petals so that reflected sunlight will produce a blue halo emerged as an alternative evolutionary strategy to attract pollinators.
Remarkably, otherwise divergent species wound up with the same lure.
Findings suggest the petal ridges that produce ‘blue halos’ evolved many times across different flower lineages, all converging on this optical signal for pollinators.