37G 



THE AMERICAN BEE JOURNAL. 



Blenen Zeitung. 



Fertilization of Flowers by Bees, etc. 



(Translated for the Bee Joukxai,.) 



During tlie past few years zoologists 

 and botanists liave devotetl much 

 earnest study to the fertilization of 

 plants ; bo('ik-shelves are weighed 

 down with their records on this sub- 

 ject. Nectaries secreting tlieir lieiuid 

 sugar only to attract insects, invite 

 them thus to gather it, either to put 

 their pollen in contact with the stigma 

 iu the same tiower, or to carry this 

 pollen to a distance to fecundate 

 another lluwer ; and thus effect a 

 cross-fertilization. For Sprengel, 

 Darwin, llildebrand, Delpino, Her- 

 mann Mulleiand J. Lubbock say that 

 this is the reciprocal adaptation be- 

 tween flowers and insects. 



"Not only," says Lubbock, "the 

 form and colors, the brilliant shades, 

 the sweet fragrance, and the honey 

 of the (lowers have undergone a grad- 

 ual unfolding through ttie unconscious 

 selection exercised by the insects; 

 but the arrangement of the colors 

 themselves, the circular bands, the 

 radial lines, the shapes, the size and 

 the location of the petals, the relative 

 position of the stamens, and the pistil 

 are all disposed for the visits of the 

 insects, and in order to insure the 

 chief end of these visits." 



The following quotation from Dar- 

 win shows how much importance the 

 new school attacliesto the part played 

 by insects, and especially hyruenop- 

 tera, in the fertilization of flowers : 

 " We can suppose that the plant, the 

 nectar of which we have seen increas- 

 ing slowly in consequence of a con- 

 tinued selection, is a common plant, 

 and that certain insects largely de- 

 pend upon itsnectarfor theirnourish- 

 ment. I could prove, by numerous 

 examples, how bees waste as little as 

 they can of their time. I would point 

 to their incisions at the basis of cer- 

 tain flowers to reach their nectar, 

 when, witli a little more pains, thev 

 couki have got in through the top of 

 the corolla. If these parts are kept 

 in remembrance, it becomes easy to 

 believe that, under certain circum- 

 stances, individual differences in the 

 curve or the length of the trunk, al- 

 though too insigniflcant for our appre- 

 ciation, may Ije of use to the bee or 

 any other insect ; that some individ- 

 uals would be more able than others 

 to procure their food, and that the 

 families to which they belong would 

 in consequence obtain a quicker de- 

 velopment, and produce more swiirnis 

 inheriting the same peculiarities. Tlie 

 tubes of the corollas of tlie common 

 red clover,, and of the incarnate 

 clover {Tiifolium pratensnnd T. incar- 

 natuin), do not appear at lirst sight to 

 differ in length ; and yet the domestic 

 bee easily reaches the nectar of the 

 incarnate clover, but not that of the 

 red, which is only visited by the 

 drones; so that whole fields of red 

 clover offer in vain, to the bee, an 

 abundant harvest of the precious 

 nectar. Jt is very fond of it, for 1 

 have often seen, but only in the fall, 

 many bees suck the llovvers through 

 holes made by drones at base of tube. 



" The difference in the length of 

 the corollas of both species of clover 

 must be very slight; and yet it is suf- 

 Hcent to cause the bees to visit one 

 flower in preference to another. More- 

 over, it is afl^irmed tliat the flowers of 

 the red clover of the second crop being 

 smaller, the bees visit them. Neither 

 do I know the truth of another asser- 

 tion recently published, that the 

 Liguriau bee. which is ordinarily con- 

 sidered simply as a variety of the 

 domestic bee, and which is often 

 crossed with it, can reach and suck 

 the nectar of red clover. Whatever 

 it may be, it would be a great benelit 

 for the domestic bee in a country 

 where this clover abounds, were its 

 trunk a little longer, differently con- 

 structed on the other side, as the fer- 

 tilization of the plant absolutely de- 

 pends upon the visit of the bees, it 

 would be much advantaged, should 

 drones become rare, were its corolla 

 shorter or more deeply divided, in or- 

 der that the beecouldsuck itsllov/ers; 

 hence, it is easy to understand how it 

 happens that a "flower and an insect 

 may slowly, though simultaneously, 

 one following the other, undergo in 

 the most perfect manner a nnitual 

 modification and adaptation by the 

 continued preservation of all the in- 

 dividuals presenting slight deviations 

 of structure advantageous for one and 

 the other. 



" Here is another instance which 

 will illustrate the complicated re- 

 lations that bind together plants and 

 animals so distant from each other in 

 nature's scale. Insects, in my garden, 

 never visit the Lobelia falgens, au ex- 

 otic plant, and that, as a consequence, 

 on account of its peculiar conforma- 

 tion, this plant never produces seed. 

 It is absolutely necessary for the fer- 

 tilization of our orchidse that they be 

 visited by insects which carry the 

 pollen from one flower to another. 

 After numerous experiments, I have 

 ascertained that the drone is almost 

 indispensable for the fertilization of 

 the pansy ( Viola tricolor), because the 

 other insects of the bee-family do not 

 visit this flower. I have also ascer- 

 tained that several species of clover 

 cannot be fertilized without the visits 

 of bees ; 20 heads of Holland clover 

 {Trifoliwn rcpens) for instance, have 

 produced '2,2'M seeds, while 20 other 

 heads, whicli bees could not approach, 

 have not produced one. The drone 

 alone visits red clover, because the 

 otiier bees cannot reach the neitar. 

 It is said that Phalence can feciuidate 

 red clover; but I must doubt it, be- 

 cause the w'eiglit of their bodies is not 

 sufficient to press down the petals. 

 We can, therefore, consider it as very 

 probable that if drones were to dis- 

 appear or to become very rare in Kng- 

 land, both i)ansy and red clover would 

 also become very rare or disappear 

 entirely."' 



Summing up the doctrine. Mr. 

 Sachs writes : "Insects are the un- 

 witting and unconscious agents of 

 poUenization ; they only visit; flowers 

 for the nectar which is their food, and 

 which is only distilled for this pur- 

 pose." (iorging themselves with pol- 

 len, they fly from flower to flower, 

 rolling themselves in the corollas to 



gather the fertilizing dust which, 

 fastening itself to their hair, so covers 

 and disguises them sometimes as to 

 make it diflicult to recognize them. 



Says Iluber : " I have seen drones 

 try in vain to reach the honey con- 

 tained in bean-flowers; the large size 

 of their heads and of their waists hin- 

 dered them from entering far enough 

 into the long tubes of these flowers ; 

 they would then turn straight to the 

 calyx, and pierce it as well as the 

 tube, with the scaly part of their 

 trunk, which, penetrating the centre 

 of the flower, would reach the nec- 

 taries, and bring out the honey with 

 which they were filled. At the same 

 time, other drones less in size, or with 

 trunks longer, would enter the corolla, 

 penetrate into the tube, and reach the 

 lioney without any trouble." 



Du Petit ThonaVs has also observed 

 that the drones and the " abeille soli- 

 taire " {Xylocopa violacea) thus vio- 

 lently gather the nectar of the " Lin- 

 aire " (Linaria vulgaris), of the" gueole 

 delonp" (Avthirnmim majus), of the 

 ''Belle de ivi/et" (Mirubilis Jalapa). 

 Kirby has often seen that the long 

 honey receptacles of the aniolies 

 { Aquilegia vulgaris) were perforated; 

 Other observations have followed. 

 ;siany other entomologists and bota- 

 nists have watched the drones at work 

 piercing the calyxes or the corollas of 

 many plants. We have often- ob- 

 served them ourselves ; and it is in- 

 deed a marvellous sight to witness 

 their excitement, when they find 

 themselves confronting, for instance, 

 a closed flower like the consonde 

 (Symphytum officimde) ; it is only after 

 tliey have assured themselves that 

 they cannot obtain a direct entrance 

 to the nectaries that they resort to 

 the piercing process, and," the open- 

 ing once made, bees crowd after them 

 for their share of the honey— the 

 crumbs of the table— for which they 

 insert their tongues into the holes 

 made for them by the noisy drones."— 



KUliCHEL. 



Experimeuts - 



Exchange. 



-Bloom Fertilization. 



Prof. Beat, of the Michigan Agri- 

 cultural College, has been conducting 

 experiments for six years with hum- 

 ble-bees and red clover. The sixth 

 experiment during 1SS2, he describes, 

 as follows : Two fine bunches of the 

 first clover crop, apparently alike, 

 were both covered with mosquito 

 netting. No insects were seen about 

 either, except what are mentioned 

 below. On June 29 a bumble-bee was 

 placed inside of one netting and seen 

 to work on the flowers ; July 10 two 

 more were introduced and seen to 

 work; on the 12th more were put in 

 and observed. On July 31, fifty ripe 

 lieads were selected from each plant 

 andthe seeds carefully counted. The 

 fifty heads on the plants where bees 

 were excluded yielded 25, seeds. The 

 fifty heads on the plant where the 

 bumble-bees were inserted under the 

 muslin and seen to work, yielded 92 

 seeds. This is nearly four" times as 

 many as were produced by heads 

 where the bees were excluded. In all 



