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With a life's experience of teaching field studies in the Forest of Dean, Brian Cave explores the ecology of rural France. More Info

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An English Naturalist in France

Bee and Woodcock orchids

May 21, 2015

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 These two orchids are common enough in our area (40 km north of Cahors).  A is the Woodcock (Ophrys scolopax) and B is the Bee (Ophrys apifera).  [scolopax is the Latin for the bird woodcock and apis=bee] Species B follows in the season very soon after A.  They look at first sight very similar, indeed identical, and they grow in almost identical locations.  So what separates them structurally and in their ecology?

First look at the enlargements of the flowers.

Both in profile look like heads and bodies of birds sitting on a velvety brown nest. The ‘head’ of the bird has an apparent beak.  In the case of the BEE on the left the beak is quite undulating. In the case of the Woodcock on the right it is fairly straight.

The ‘ head’ end in both have yellow cheeks wherein is held the pollen masses aggregated as two ‘pollinia’ in each case.  But if you can make it out in the case of the ‘bee’ orchid the two pollinia have fallen down and are stuck onto the ‘chest’ of the ‘bird’.  In the ‘woodcock’ they remain inside the cheeks but at the top of the ‘chest can be seen a projection (there are really two rather in the position of look alike mammary glands).  Those projections are sticky glands.  they are present also in the ‘bee’ orchid flower but in the picture here are covered by the fallen pollinia.  The stalks of these pollinia are attached to the glands on the ‘chest’.  I will return to these phenomena  below.

Now look to the far left of the brown velvety ‘nest’ or ‘labellum’ – which is its true name.  This labellum is one of the three petals of the flower.  The other two petals ARE NOT the purple apparent petals which are easily seen.  Just to make the structure more confusing the large purple petal-like structures are the sepals – the outermost parts of the flower.  One of the other two petals in the ‘woodcock’  flower is the tiny purple petal just poking out towards the left.  In the ‘bee’ flower the two backward poking petals are hardly visible at all and are represented by two brown structures, just one of which can be seen to the left on which the bird shaped upper part of the flower is sitting.

Lastly, if you look the ‘woodcock’ flower, it has on the labellum a tongue like structure pushing out straight to the right.  In the ‘bee’ flower this tongue pokes downwards.

Pollinia on the end of a needle

To return to the pollinia.   In most orchids these are transported from one flower to another  by the pollinating insects.  The picture demonstrates the action by using a small fine knitting needle. The sticky glands carrying the pollnia get stuck onto the head of the insect and carried away,  Perhaps in this case carried  by bees who are probably confused by the appearance of the flower – but who can say?  But this is not so often the case in the ‘bee’ orchid flower.  In that case the pollinia most often fall down still attached to their stalks before any insect is capable of transporting them away.  When they fall they hit the receptive stigma of the flower (on the chest of the bird-like shape) and so self-pollinate the flower.

These two species seem to me to be quite clearly closely related, though a main text places them in two different groupings.  But then others have noted the similarities.  It is quite possible that the self-pollination habit has in time separated the ‘bee’ from the ‘woodcock’ 

 

by Brian Cave. Find out more about Brian Cave here.