A question about nectar

[Polly]

I have not been able to find the answer to my query but know that someone here is bound to know the answer... and it's probably ever so simple!!

As we know butterflies (and bees) fly from flower to flower checking on nectar availability. Does nectar continue to develop and mature in the flower so that it is worth the insect going back to check in case more is ready? Or once it is supped is that it?

Thanks

Polly

[NickB]

Hi Polly - I'm no expert - but I seem to remember something about (some?) flowers under UV light change colour to show insects that they have been pollinated and not to waste their time there.....of course I may have got it wrong, but it sort-of-seems-to-make-sense. That said I have watched bees flitting from flower to flower and they do visit flowers which have been visited by other bees, so I don't know (I know, I should get a life )
N

[Polly]

Thanks for your response Nick.

Are you saying that once a flower has been pollinated then there is no more nectar so butterflies and bees won't bother to look there again?

[Susie]

From the little I know about flowers it is the case that they plants ooze nectar continuously (albeit at a slow rate) and the insects feed on this and do come back later on when more has been produced. Obviously once the plant has been pollinated it would have no need to make more nectar and would put its energy into developing the seed resulting from polination.

I think pollen, on the other hand, is only created in one batch (if you know what I mean) and once it is gone it is gone.

[NickB]

Thanks Susie!
I guess that clears that bit up; pollen harvested by insects = no more pollen left = (probably) pollinated = no need to produce nectar....

[Polly]

Those replies have really answered my query - thanks very much!!

Now I know that nectar is produced continuously and an insect that returned to a given flower, after a period of time, would find more nectar there (unless the flower has been pollinated). Right?

Regards

Polly

[Matsukaze]

Bumblebees are capable of detecting which flowers have been visited recently by other bumblebees (from scent marks left by the previous bee, if I remember rightly) and should only forage for nectar from these plants. I imagine this is why they select flowers seemingly at random from plants with many flowers (foxgloves, viper's bugloss), visiting only a minority.

Butterflies use some of the same nectar sources as bumblebees. I am not sure if they can detect whether these actually contain nectar before they try to take a drink.