|By staying on the outside of a flower, carpenter bees take the nectar without pollinating|
Morning glory flowers have long narrow throats that make it difficult for a big carpenter bee to climb inside.
|Sizing up the throat: nope, too narrow|
So they sit on the top of a flower, make a slit at the petal base (corolla) and get the nectar anyway.
|Climbing to the top is hard work: fragile petals are crumpling and the whole flower is swaying precariously|
Plants produce nectar as payment to pollinators for transferring pollen from flower to flower. By making a slit in the corolla, the carpenter bees avoid touching the pollen and therefore, take the payment without doing the job.
That's why it is called nectar robbing.
|Making a slit and getting to the nectar|
A few flowers that I examined all had slits at their bases and there were no other bees that I could see, meaning probably that carpenter bees were pretty thorough in getting most of the nectar out.
|The slit at the corolla: evidence of robbery|
I have also witnessed a comic episode of a bee actually trying to climb inside a morning glory flower. After it got the nectar, it tried to get out backside first, lost its footing and fell out of the flower's throat.
|A stumble bee?|
It tried to grab onto a petal...
... but the petal folded, so it fell on its head again (: .
|Are they serving alcohol in there? Where do I line up?|
Finally it climbed back in, turned around, and came out head first.
After all these antics, the flower was ripped apart, and probably completely useless for pollination.
|I have read somewhere that it is typically female carpenter bees that cause so much destruction|
I have to say these bees are not malicious by nature, and where a flower presents itself conveniently, they will take its nectar the conventional way and do their job as a pollinator.
|Flowers on a sweet pea shrub make nectar easily accessible, so they get pollinated and I pull up hundreds of seedlings underneath the bush...|
But they will do what they have to do to get their food :).