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AMERICAN BEE JOURNAL 



April 



sect, and the globular enlargement of 

 the rectum is where this probably 

 takes place. Boussingault, who has 

 analyzed the honeydew with a polar- 

 izer, gives the following result for 

 samples examined in July and Au- 

 gust: 



July August 



Cane Sugar 48.86 55.44 



Inverted sugar 28.59 24.75 



Dextrine 22.55 19.81 



100.00 100.00 



When the sugar content of honey- 

 dew is taken into account, it is not 

 strange that ants, wasps, butterflies, 

 moths and bees of many kinds, in- 

 cluding the honeybees, should seek it 

 for food. The western Indians were 

 also aware of the sweetening proper- 

 ties of this substance, since they col- 

 lected the leaves that were thickly 

 coated with honeydew, washed them 

 off in water, and boiled down the 

 water, producing a crude brownish 

 sugar resembling an inferior grade 

 of maple sugar. 



The honeydew is evidently accumu- 

 lated in the globular portion of the 

 rectum in most species and extruded 

 as a minute bubble. There is consid- 

 erable variation in the impetus that 

 leads to the freeing of the bubble. It 

 is likely that in many species it is 

 simply the pressure of the excretion 

 upon the walls of the rectum, but in 

 others the Insect may be led to give 

 up its excretion by the stroking of 

 its abdomen. This is particularly true 

 of the plant lice and certain scale in- 

 sects. These insects are generally 

 attended by ants, which gently stroke 

 the back of the plant louse with (heir 

 antennae, and are rewarded with a 

 small drop of honeydew. This may 

 be repeated, and the plant louse may 

 give up more than one drop, but as a 

 rule, the ant, after receiving one drop, 

 passes to another individual and re- 

 peats the stroking of the back. Time 

 must elapse, in the case of most in- 

 dividuals, before a second drop can 

 be discharged. In some plant lice that 

 do not produce much honeydew the 

 anus is surrounded by long hairs for 

 holding the drop of honeydew after it 

 is extracted, and so it will not be lost. 

 Practically all flowering plants are 

 infested by honeydew-producing in- 

 sects. The great majority of these 

 are different species of plant lice. 

 Most of the species live upon the ex- 

 posed surfaces of the plant, others 

 live upon the roots, and still others 

 produce galls upon the leaves or buds 

 in which they live. The root inhab- 

 iting and the gall inhabiting species 

 produce only a negligible amount of 

 honeydew, while those species that 

 live exposed on the leaves, usually on 

 the under surface, where the outer 

 covering of the leaves is more deli- 

 cate, produce great Quantities. The 

 plant lice are fixed in position and 

 those that live upon the leaves, be- 

 cause of their sedentary and gregari- 

 ous habits, are exposed to the attacks 

 of many enemies. It is a well-known 

 fact that certain species of ants pro- 

 tect the plant lice and they are often 

 figuratively described as their cows. 

 The ants drive away enemies, build 

 sheds over them, and may carry the 



plant lice into their nests upon the 

 approach of winter and return them 

 to the plant again in the spring. The 

 plart lice, in return for this protec- 

 tion and care, excrete at the bidding 

 of the ant considerable quantities of 

 honeydew. It is an initeresting fact 

 that those species that live e-xposed 

 and need the most protection should 

 produce the greatest quantity of 

 honeydew. There is, as Wheeler 

 states, a symbiotic (living together. — 

 Editor) condition existing between 

 the two kinds of insects, while one 

 kind is not wholly, it is in great part, 

 dependent upon the other, and it is 

 not unlikely the development of the 

 honeydew-producing ability of the 

 exposed species has been increased 

 from the protection received from the 

 ants. 



When the insects are not attended 

 by ants, the drop of honeydew in- 

 stead of being gently extruded so 

 that it can be seized by the ant, is ex- 

 truded with a jerk, so as to throw it 

 some distance beyond the body. The 

 drop is carried into the air and 

 alights upon the upper surface of a 

 leaf below or upon the ground. If the 

 colony of insects is large and the 

 amount of honeydew produced is con- 

 siderable, so that there is much more 

 than the attending ants can use, the 

 upper surfaces of the leaves become 

 spotted, or more frequently covered, 

 with the honeydew that is thrown 

 into the air. The surfaces of the leaves 

 have a glossy appearance, as if they 

 had been varnished. When the pro- 

 duction of honeydew is of considera- 

 ble volume, it may drip from the tips 

 of the leaves, and to one standing un- 

 der the tree give the effect of a 

 shower of rain. The raining of honey- 

 dew from trees has been reported so 

 many times by different observers 

 that it cannot be considered an un- 

 usual phenomenon. It is at such times 

 that honeybees collect honeydew in 

 enormous quantities, producing honey 

 of an inferior quality. 



When one considers the raining of 

 honeydew and its production in mass, 

 one is immediately led to the conclu- 

 sion that each plant louse must pro- 

 duce a large volume of honeydew. 

 Busgen, who has studied this matter 

 exhaustively, showed, however, that a 

 single plant louse on maple produced 

 only forty-eight drops in twenty-four 

 hours, a single plant louse on linden 

 nineteen drops, one on a different 

 kind of maple nine drops, and one on 

 rose only six drops. Since Busgen 

 made numerous counts of the number 

 of drops produced, there is no ques- 

 tion that the amount produced by 

 each individual insect is very small. 



In order to appreciate how such a 

 volume of honeydew can be produced 

 as has been described, the number of 

 individuals engaged in its production 

 must be realized. The insects that 

 produce honeydew are of such size 

 that several hundred might be colo- 

 nized on the under side of a single 

 maple leaf. Fifty ordinary sized plant 

 lice would not fill a teaspoon of aver- 

 age size. The often-quoted statement 

 of Huxley is that the produce of a 

 single plant louse in the course of 

 ten generations, supposing all indi- 



viduals to survive, would weigh more 

 than five hundred million of stout 

 men, that is, they would weigh more 

 than the entire population of China. 

 Such an idea seems preposterous. But 

 Buckton, a prominent English student 

 of plant lice, offers the following cal- 

 culation. For the sake of simplicity 

 the calculation assumes that each 

 plant louse lives twenty days and that 

 at the end of this time each plant 

 louse shall have produced twenty 

 young. It should not be forgotten 

 that many individuals may live more 

 than twenty days and produce more 

 than twenty young and that each be- 

 gins to produce young at the age of 

 five days. Then, at the end of twenty 

 days, there would be produced twenty 

 individuals ; at the end of forty days, 

 400 individuals; at the end of 100 

 days 3,200,000 individuals; at the end 

 or 200 days, 10,240,000.000.000 individu- 

 als, and at the end of 300 days, 32,768,- 

 000,090,000,000,000 individuals. If it is 

 assumed that 1,000 plant lice weigh 

 one grain, and a stout man weighs 

 2,000,000 grains, then the weight of a 

 single man would be equal to that of 

 2,000,000,000 plant lice, and the weight 

 of the descendants of the single plant 

 louse at the end of 300 days would 

 equal the weight of 16,284,000,000 men, 

 or several times the weight of the 

 entire population of China. If you 

 will e.xamine the buds of an apple 

 tree during the winter season, you 

 will find around each terminal bud 

 from one to six or more minute black 

 globular objects. Each of these is 

 the egg of an aphid. If you were to 

 count the number of terminal buds 

 on a full grown apple tree and then 

 estimate the number of plant louse 

 eggs borne by the tree, you will have 

 some idea of the possible number of 

 plant louse inhabitants of this tree 

 next spring. Then just imagine that 

 each of these eggs should produce a 

 stem mother each -with a number of 

 descendants such as calculated by 

 Buckton, and I can assure you that 

 this calculation is much below rather 

 than above the actual number. I 

 think you will agree with me that 

 there would be no room in this world 

 except for plant lice, and even if each 

 individual was producing only ten 

 drops of honeydew in each twenty- 

 four hours, not only the other inhab- 

 itants, but the plant lice themselves 

 would be drowned in the volume of 

 honeydew produced. This calculation 

 is given in order to make the reader 

 appreciate the enormous number of 

 individuals that may be produced. It 

 is rot known how many of the indi- 

 viduals of each generation will sur- 

 vive, but there is a vast army of pre- 

 dacious and parasitic insects who 

 make it their main duty to destroy 

 and hold in check the overdevelop- 

 ment of plant lice. Suppose only one 

 per cent of this innumerable host sur- 

 vived and produced honeydew, is it 

 strange, when the number of sur- 

 vivors is slightly increased, either 

 through favorable conditions for the 

 development of their enemies or fa- 

 vorable weather conditions for the 

 production of plant lice, that it should 

 not be an unusual occurrence to have 

 trees actually raining honeydew? 



