ECOLOGICAL 221 



fear that the varied acidity or alkalinity of such manures may be 

 — in many cases, as notably in Mediterranean France, but if so 

 probably elsewhere also — acting prejudicially on the desirable soil 

 bacteria; and they are now consequently beginning to experiment 

 towards the encouragement of these, with hopes of substantial 

 manure-economy accordingly. 



THE BEE DANCE. — ^When an exploring bee discovers some flowers 

 with abundant nectar, it takes in as much as it can hold and makes 

 for home. In a short time there are more bees on the scene. How 

 do they know that there is treasure-trove and how do they find 

 it? As already noted, the experiments of Frisch have thrown 

 light on this. When a bee that has sucked to the full returns to 

 the hive, it indulges in a peculiar "round dance" on the comb. 

 This excites the workers in the immediate vicinity and they hurry 

 forth to find some nectar for themselves. But before issuing from 

 the hive they nose at the discoverer, and thus get an olfactory 

 clue to the kind of flower to be sought after. The discoverer does 

 not fly with them, that is certain. They explore for themselves. 

 But they have got the scent as a clue. 



But what if the nectariferous flower has no scent? Frisch's 

 answer is that a hive-bee, excited by a discovery, sprays the blossom 

 with a characteristic scent formed in a protrusible glandular pocket 

 near the hind end of her body. This scent serves as a teU-tale clue 

 to the searching bees. 



It has been noticed that when a profitable patch of flowers begins 

 to be exhausted, the visits of "new bees" begin to drop off. In a 

 short time they stop. How is this regulated? The answer is that 

 when a bee returns with little nectar she does not dance ; and thus 

 no more searchers go forth. When the bees are collecting pollen, 

 not nectar, there is the same sort of "dance language", but the 

 nature of the dance is different ! 



HONEY. — In connection with animal industry on the one hand, 

 and the evolutionary importance of nutrition on the other, we 

 wish to take the concrete case of the honey of bees. Honey is trans- 

 formed nectar that has passed into and out of part of the food-canal 

 of the bee ; and nectar is an overflow of the sugar that plants make 

 in their everyday photosynthesis. It sometimes exudes away from 

 the flower altogether in extrafloral nectaries, but floral nectaries are 

 naturally more frequent, for they attract the insect visitors to 

 come to the right place, that is to say to the flower, where cross- 

 pollination may be effected. When the pollination has come about, 

 then the nectaries close, and the surplus sugar can be diverted 

 into the swelling fruit. If the fruit is dry and not sweet, the surplus 

 sugar can be stored as starch in the seeds or remain as a reserve 



