Posted by Gwen Pearson

Writer. Nerd. Insect Evangelist. Have you heard the good news? BUGS!


  1. There’s a few aspects of pollination which I’m not quite clear on, wondered if you could help.

    Does a flower need to be pollinated multiple times? As flowers keep producing nectar after pollinators visit, presumably they do?

    Also, I’ve read that bees will specialise in collecting different products and the majority of bees in a colony collect nectar only, a smaller percentage pollen only and a small minority both nectar and pollen. Does it matter from the flower’s point of view whether the bee is collecting nectar/pollen/both, or is it irrelevant as it’s the pollen that happens to stick to the bees’ bodies that pollinates other flowers?


  2. Robert Bevins June 22, 2012 at 9:25 pm

    Depending on the number of eggs or ovules a flower has, It needs at least that many grains of pollen to be able to produce a maximum number of offspring. Wikipedia has a good diagram of a flower, which may help. The male parts (the anther and stamen) produce tremendous amounts of pollen in order to spread as many copies of the plant’s genes as possible to as many flowers as possible. That some is lost to bees is acceptable as the bee will probably visit another member of the species soon enough, drop off some pollen and perhaps even visit yet another plant. Wind pollinated plants produce ridiculous amounts of pollen and very little ever reaches another flower, so while using an insect can be costly, it is more efficient than other means. Although many won’t reach female parts (stigma, style and ovary), and those that do have pollinated the plant, but this is not the same as fertilization. Most of the pollen that a stigma is pollinated with will not manage to fertilize an ovule. To do that, the pollen produces a tube of cells that burrows down the style into the ovary, where it will fertilize a single ovule.

    If you have access to a microscope, you can brush pollen from a flower (lillies from the grocery flower shop are perfect) onto a slide and you will see thousands upon thousands of grains. If you then cut open the ovary (very carefully) with a razor knife, you can see lots of internal structures containing the ovules. I have heard that if you add a drop of sugar water to a slide of live pollen, it will open and produce a pollen tube. I have never seen this happen, but since I have a USB scope tucked away in a box somewhere, perhaps I should try with my own lilies instead of store bought ones. They should be opening up pretty soon.

  3. Thanks so much for such a detailed reply Robert, that helped me understand the process much more clearly. Flowers and insects are wonderful things.

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