444 



AMERICAN BEE JOURNAL 



November 



colors. Thus gradually developed the 

 notion that insects (especially bees) 

 can see at a distance, that they per- 

 ceive color, and that they show color 

 preference. 



From 1793 down to the present 

 time at least a score and a half of 

 workers have given important evi- 

 dence for or against these notions. 

 Most prominent among those in op- 

 position was Plateau, who published 

 papers between 1895 and 1907. Kel- 

 logg in his book on "American In- 

 sects" (page 581) said that Plateau 3 

 publications had made it "necessary 

 for more experiments to be devised in 

 support of the theory that floral adap- 

 tation of color is due to color prefer- 

 ences of insect visitors." Plateau's 

 papers did start the work of gatherin>j 

 evidence in regard to color vision in 

 insects — especially in case of tna 

 honey bee — all over fgain. Most re- 

 . cent in this country is the work ol! 

 J. H. Lovell and C. H. Turner. In 

 Europe the works of Wendt, Forel, 

 Exner, Andrae, Buttel-Reepens, and 

 many others might be mentioned- - 

 and finally, the work of K. Von Frisch 

 and C. Hess. In 1914 Von Frisch 

 presented a paper and made certair. 

 demonstrations before a Zoological 

 Society of Freiburg, where he suc- 

 ceeded in convincing his audience, by 

 demonstrations, that fish distinguish 

 color, and that honeybees can distin- 

 j,jish color. Von Frisch had fed fish, 

 kept in a glass aquarium, for many 

 days on yellow food. Then when he 

 pasted a small bit of yellow paper 

 upon any shade of gray or among 

 other bits of blue, red or green paper, 

 and caused this to approach close 

 against the side of the glass aquari- 

 um, the fish (trained to eat yellow 

 food) darted toward the bit of yel- 

 low paper, but not toward that of anv 

 other color — according to the report. 

 Similarly he showed that other fish, 

 trained to eat red food, seemed to 

 recognize red. His demonstration 

 with bees was as follows: On a table 

 he arranged a series of fifteen giay 

 papers which led in gradual, continu- 

 ous gradation from white to black. 

 In a chosen place a blue paper of sim- 

 ilar size to the others was inserted 

 in the gray series. Over all the pa- 

 pers a thick glass plate was laid, and 

 on this plate, above each paper, i 

 little watch glass was set; but only 

 that watch glass above the blue paper 

 was filled with sugar syrup. The 

 table was exposed where the bees 

 came in numbers, after a time, to gtfc 

 the syrup. Finally, after periods of 

 about twenty minutes, when the bees 

 had emptied the watch glass above the 

 blue paper, it was refilled, and each 

 time the position of the blue paper 

 was changed in the gray series in or- 

 der to avoid having the bees become 

 accustomed to getting the syrup in n 

 definite place in the series. The bees 

 had bf-tr. trained thus for two dayf. 

 when the demonstration was made. 

 On the day of the demonstration, a 

 new series of clean papers was ar- 

 ranged under the glass plate with tho 

 blue paper in a new position froia 

 Iha', of the last feeding. Above each 

 paper (even above the blue this time) 

 s clean, empty watch gl^g^ was placed 



and the table then exposed to the 

 bees. It was reported that the bees 

 flew at cnce toward the watch glass 

 above the blue paper and alighted 

 upon it. Also, it is reported that 

 (when the table was removed) bees, 

 seeking nourishment, flew toward 

 those spectators who had blue cra- 

 vats cr blue hat bands. 



Opposed to this experiment w;th 

 bees which Von Frisch demonstrated, 

 Carl Hess has urged especially the 

 following experiment: Bees v/ere 

 trained to take syrup from a glass 

 placed t.bove blue paper. ThcK, 

 having prepared a spectrum made up 

 of 158 different contiguous strips of 

 colored paper, the whole ,vas covered 

 with a plate glass. Hess says that he 

 then drew r. long, narrow streak of 

 syrup from end to end over the glass 

 plate above the spectrum of colors, 

 and f xposed this to the bees. It now 

 the bees would pay especial attention 

 to color rather than to odor of Tood, 

 he says '..hey should have alighted at 

 frst in numbers only above the blue 

 portion of the spectrum. Instead of 

 doing so, however, he reports that 

 they flew to the food regardlessly, 

 nov,- abcve this and now above that 

 color of the spectrum, and so al'ghted 

 everywhere upon the food. 



Thus Hess, in his latest paper 

 (1918; maintains that bees do not 

 perceive color at all, and he bases 

 his conclusions in regard to co:ot 

 blindncos m the honeybee upon ex- 

 periments which may be classified un- 

 der three headings: I. Spectrum ex- 

 periments. 11. Tests with colored 

 lights of '.arying intensity. III. 

 Training experiments. His spectrum 

 experiments tend to establish the fol- 

 lowing points . First, within certain 

 limits, confined bees always go to- 

 ward the strongest light when sud- 

 denly exposed to a graded band of 

 light through glass along the side of 

 their container. Secondly, when bees 

 confined in the dark in a long paral- 

 lel sided coi tidner are suddenly ex- 

 posed to the light of a prism spec- 

 trum thrown against the glass side or 

 top of their container, they congre- 



gate in the yellow green to green por- 

 tion of the spectrum — showing, as he 

 concludes, that this portion of the 

 spectrum seems brightest to them. 

 Now it is well known that to a normal 

 man, suddenly exposed to a bright 

 spectrum in this way, the yellow por- 

 tion of the spectrum seems brightest. 

 On the other hand, to a totally color 

 blind man the yellow green to green 

 portion of the spectrum seem, bright- 

 est — and Hess points out thai in his 

 tests it is the same with the bees as 

 with the totally color blind man. 



The experiments with colored 

 lights of varying intensity tend to 

 show, according to Hess, that it is tie 

 intensity of the light and not the 

 color which attracts bees or causes 

 them to show preference. By chang- 

 ing the intensity only (not the color) 

 of the light to which confined bees 

 were exposed, he says he could 

 change "blue-loving" bees, for exam- 

 ple, into "red-loving" bees, and then 

 back again. 



The "training experiments" of 

 Hess were quite varied. For exam- 

 ple, he used diff^erent colored pieces 

 about hive entrances in such a man- 

 ner that they might be quickly re- 

 moved or changed, or covered with 

 glass or not as he wished, and he 

 claims that in all cases where it 

 might seem that the bees acted as if 

 they discerned difference in color, he 

 was able to show that it was actually 

 difference in intensity of light which 

 guided the bees in some cases, or more 

 often the sense of smell, and not 

 really color in any case. Again, he 

 exposed food to bees for weeks above 

 a certain color, after which he ar- 

 ranged checker boards of different 

 colors and checker boards of white 

 and black which he could shift quickly 

 under a sheet of plate glass upo;i 

 which food was exposed (without dis- 

 turbing the plate glass), and the 

 "color trained" bees, he says, would 

 take food as quickly above one color 

 or one shade as above another. 

 Finally, among other tests, he ar- 

 ranged the "paper strip spectrum and 

 streak of syrup or honey" experiment 





Exhibit of C. B. Talmcr, of Brailshaw, Neb., at a local fair. 



