The Mediterranean orchid Ophrys gets pollinated by a species of bee through ‘sexual deceit’. Suppose that, during evolution, the colour patterns of the female bee change slightly.
According to NCERT, which of the following is expected?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Pollination success of the orchid will be reduced unless the flower co-evolves to keep its petal resembling the female bee.
Ophrys offers no reward to its pollinator. One petal of its flower looks very much like the female bee in size, colour and markings. The male bee takes it for a female, pseudocopulates with the flower and gets dusted with pollen, which it carries to the next flower. The whole trick works only as long as the petal keeps looking like the female bee. This is co-evolution.
Option (1) Pollination success of the orchid will rise, as the male bee will be attracted to the flower more strongly. — Incorrect. The male bee is drawn by the likeness of the petal to the female. Once the female changes, the petal no longer matches, so the attraction becomes weaker, not stronger.
Option (2) Pollination of the orchid will not be affected, as the flower offers nectar as a reward to the bee. — Incorrect. Ophrys gives no reward; it depends on ‘sexual deceit’. So a change in the female bee does affect its pollination.
Option (3) The female bee, in place of the male bee, will begin to pseudocopulate with the orchid flower. — Incorrect. Only the male bee pseudocopulates with the flower, because it mistakes the petal for a female. A change in the colour of the female does not make the female visit the flower in this way.
Option (4) Pollination success of the orchid will be reduced unless the flower co-evolves to keep its petal resembling the female bee. — Correct. The male bee visits only a petal that looks like its female. If the female changes, the orchid has to change its petal along with her to keep getting pollinated.
NCERT Extract:
Mutualism – “… Not all orchids offer rewards. The Mediterranean orchid Ophrys employs ‘sexual deceit’ to get pollination done by a species of bee. One petal of its flower bears an uncanny resemblance to the female of the bee in size, colour and markings. The male bee is attracted to what it perceives as a female, ‘pseudocopulates’ with the flower, and during that process is dusted with pollen from the flower. … Here you can see how co-evolution operates. If the female bee’s colour patterns change even slightly for any reason during evolution, pollination success will be reduced unless the orchid flower co-evolves to maintain the resemblance of its petal to the female bee.”