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SYMBIOSIS 



Very remarkable evidence enlightening us concerning the 

 state of Norm-Symbiosis in their case, namely that of the Neotteae, 

 is provided by Darwin, first with regard to Epipactis palustris. 

 Apart from several small flies (Coelopa frigida) , and three or four 

 distinct kinds of Hymenoptera (one of small size being Crabro 

 brevis) visiting these orchids, there is a large fly, Sarcophaga 

 carnosa, haunting them, a fact which Darwin finds the more 

 remarkable as the Sarcophaga frequents decaying animal matter 

 and the Coelopa haunts seaweed, occasionally settling on flowers. 

 We are further told : 



The Crabro also, as I hear from Mr, F. Smith, collects small beetles 

 (Halticae) for provisioning its nest. It is equally remarkable, seeing how 

 many kinds of insects visit this Epipactis, that although my son watched 

 hundreds of plants for some hours on three occasions not a single humble- 

 bee alighted on a flower, though many were flying about. 



The Sarcophaga had already been mentioned by Darwin in 

 connection with the Fly Orchis, the scentless and inconspicuous 

 flowers of which, it will be remembered, he suspected of possessing 

 " sham-nectaries." To be seen in such low company as these 

 flies does not redound to the credit of the orchids. I should 

 be inclined to consider the respective " attractions " as belonging 

 to the pathological order, closely akin to those by which a beast 

 of prey becomes aware, even at a considerable distance, of the 

 presence of diseased individuals. And if these orchids are so 

 poorly connected in the insect world, this, in my opinion, is for 

 the reason that they have become as in-feeders, too indolent for, 

 and too ineffective in, Norm-Symbiosis. 



Two other Epipactis, E. latifolia and E. purpurata, are 

 frequented by " swarms of wasps " the highwaymen amongst 

 Hymenoptera and Darwin states : 



It is very remarkable that the sweet nectar of this Epipactis should 

 not be attractive to any kind of bee. If wasps were to become extinct 

 in any district, so probably would the Epipactis latifolia. 



Again it must be pointed out that although the nectar be, 

 " sweet," it may not be of such a composition as to suit it for the 

 purposes of advanced Norm-Symbiosis. It may be an article 

 " de luxe " rather than a food ; it may be fit for scavengers and 

 " mixed " feeders rather than for symbiotic cross-feeders. We 

 have not yet learned to discriminate with regard to Nature's finer 

 forces as purveyed by food ; but during the next 500 years we 

 may learn a little more respecting these important matters. 



