1. A researcher observes a moth that is highly attracted to a particular species of
flower. The researcher wants to determine if smell is an important factor in this
attraction. He or she could do the following and then observe the moth’s response:
a. Contain the flower on the plant in a clear plastic bag
b. Contain the flower on the plant in a net which moths cannot pass through
c. Remove the flower from the plant
d. Remove the petals of the flower

The correct answer is option a: Contain the flower on the plant in a clear plastic bag. This isolates smell while preserving visual cues, allowing direct testing of olfactory attraction in moths.​

Option Analysis

Clear plastic bag (a): Clear plastic permits visual attraction to the flower but traps volatile scent molecules inside, preventing smell dispersal. Moths detect odors via antennae, so reduced visits confirm smell’s role. Studies use bags to capture/control floral odors without blocking sight.​

Net enclosure (b): Fine nets block moth access physically while allowing some odor and visual escape. No behavioral response observation occurs as moths cannot approach, failing to isolate smell.​

Remove flower (c): Eliminates both smell and visual cues entirely. Moth absence proves nothing specific about smell versus sight.​

Remove petals (d): Petals provide visual appeal and house scent glands; removal disrupts both, confounding results. Odor-producing tissues remain partially.​

Moth flower attraction smell experiments reveal how pollinators like moths use olfactory cues to locate nectar sources. Researchers test smell’s role by isolating scents from visuals, crucial for understanding plant-insect interactions in ecology and CSIR NET life sciences.​

Why Plastic Bags Work Best

Clear plastic bags contain flower volatiles on the plant, blocking smell release while maintaining visual appeal. Moths, guided by antennae, ignore bagged flowers if odor drives attraction, as shown in wind tunnel studies with hawkmoths. This method confirms olfaction without altering plant structure.​

Flaws in Other Methods

• Nets prevent physical approach, blocking response observation.

• Flower removal eliminates all cues.

• Petal removal impacts both sight and partial scent.

These fail to isolate smell specifically.​

CSIR NET Exam Insights

Such questions test experimental design in behavioral ecology. Focus on controls isolating variables like vision versus olfaction in moth behavior.​