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Good question that, Mike, wonder if anybody knows?


It works much the same way as with the animal kingdom - those who are of one species can only fertilise others of the same species.

No matter how amorous a tom cat may feel, even if he managed to find a co-operative dog, there would be no offspring - the genetics do not match.

Plants have evolved so that those of similar species grow in similar conditions and bloom at similar times of year thus increasing the odds that a visiting bee, going from flower to flower,  will have sufficient pollen of the same variety on it's 'fur' to rub off onto the stigma in the flower.

A more complex bit comes when we consider fruit like some apples, who require pollen from a different variety of apple tree - this is because in these plants the stigma rejects pollen from genetically similar plants.

Is that of any help? 


Evolution and numbers, Mike.  A typical plant will produce about a billion pollen grains.  Many plants, while being capable of being pollinated by many different insects, have evolved to use one or two pollinating species in particular which they attract in a wide number of ways (eg by mimicking insect mating hormones);  This makes it more likely that a "preferred" pollinator is more likely to visit another plant of the same species and thus transfer the pollen.

The downside is that these interactions are so complex that the humble human race is unlikely to ever be able to collate all of the information, so we will continue to only find out when our activity leads to the extinction of yet another species.  A good example of this complexity is the Brazil nut, which was studied for decades (possibly over a hundred years) before it was understood:



You need to look at some pictures of pollen grains taken under a microscope, they are of many different shapes and sizes. So like the children's toy you can't fit a square shape into the triangular hole.

Jim Macd

Hi Mike,

many plants are self fertile, so that's easy, no explanation needed. Others need pollen from another plant of the same or similar species. Bees tend to stick to the same flower on that run. Not always, especially if there's just one plant of that species but they will go from flower to flower of that species passing on the pollen if there's lots of flowers of that species. I think that's what you're asking.


Steve 309

As Fleurisa (nice name!) says, the pollen grains of different species are different shapes.  The ends of the stigmas have complementary shapes on the, so only pollen of the right species will fit.  There are often (I believe, but I'm no expert) chemical incompatibilities too.

Honey bees tend to concentrate on one species at a time, which makes the process less wasteful.  No idea about other pollinators.


I think its as Jim says. A bee will spend most of its time on the same type or species of flower. So that bee picks up pollen from the first (for example) rose, and then spends the rest of the day on roses. So roses get pollinated in an area. Another day it might have a preference for lavender and spend all day on lavenders. It doesn't go from rose to lavender to dahlia. That would, as you say, mean that the plants don't get pollinated by the right species.

Jim Macd
Mike Allen wrote (see)

Thanks friends.  However sad to say.  I feel that my question remains unsolved.  

Your questions is probably unanswered Mike because none of us really knew what you were asking as your question didn't make sense. 

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