As promised, the topic of mutualism in coevolution continues!!
Yay!! This week is about the extraordinary lengths that plants go to ensure their
flowers are pollinated.
Flowers produce a store of nectar (corolla) within them as a
reward for pollinating organisms transferring their pollen from one flower to
another. What happens when pollinating insects evolve their proboscis so that
they can reach the nectar store within the flower without having to land?
To reduce the risk of being disadvantaged, flowers began to
increase the depth at which they store their nectar; forcing the insects to get
close enough to acquire pollen. This process is constant as the insects
continually increase their proboscis length and the flowers continually
deepening their corolla to accommodate (Anders Nilsson, 1988).
A prime example of
this coevolution is seen in the photo below of a Morgan’s Sphinx moth extending
its phenomenal proboscis into a Comet Orchid, which has an equally phenomenal
corolla depth.
References:
http://news.discovery.com/earth/plants/top-10-evolutionary-tricks-for-pollinators-1310112.htm
- date sourced 31/03/14
Anders Nilsson, L. 1988. The evolution of flowers with deep
corolla tubes. Nature, 334, 147-149.
What a lovely little relationship!
ReplyDeleteWow! That’s a very long proboscis! I’m curious as to why pollinators would not want to land on the plant? Surely flying is energetically expensive and landing would make much more sense? Nice example.
ReplyDeleteOne issue with this flower evolution with hawk moths is that sneaky insects can by pass the system and just eat the base of the flower to steal the nectar.
ReplyDeleteFor further flower co-evolution stuff you could check out pollinator syndrome
Thanks Merric! I will definitely check the pollinator syndrome out.
Delete