| A Biometrical Study
of the Influence of Size of Brood Cell Upon the Size and Variability
of the Honeybee (Apis mellifera L.) by Roy A. Grout, 1931 |
| REVIEW OF LITERATURE 1. Length of proboscis and its relation to honey storing ability. The length of proboscis, its relation to honey storing ability and, in particular, its relation to the acquisition of nectar from red clover rose to a peak in this country at the very beginning of the present century. Previous to that time a few observers had noticed honeybees working on red clover, and Rankin (56) had successfully attempted to breed a strain of bees having long tongues. These remarkable traits soon disappeared, however. Root (59) was the first great disciple of the long-tongued worker bee. He discovered in one of his apiaries a colony which was working on red clover. Upon measuring the tongue reach of these bees, he discovered that this colony had an unusually long tongue reach, 0.21 inches, whereas the average tongue reach was only 0.16 inches. He continued by raising queens from the mother of this colony and sold them for "red clover queens". This desirable quality shortly disappeared due to the inability to control the queen's mating. It is of interest to note that Kulagin (30) measured the length of proboscis of ten bees that were the progeny of four Root queens that had been sent to Russia by Titoff and found that the average length was 6.22 mm. as compared to an average of 6.21 mm. for the common black bees of Central Russia. The contentions of Root regarding the tongue reach of these bees and their ability to acquire nectar from red clover raised a voluminous controversy which lasted until the middle of the year 1902 when it was dropped as suddenly as it commenced. Beekeeping savants such as Miller (46), Doolittle (22), Dadant (16), Gillette (27), Getaz (25), Cook (15), Swarthmore (64) and many others investigated and wrote concerning the subject. The greater part of the above mentioned believed that the longer proboscis was directly related to a greater storing ability in spite of the fact that very little scientific research was undertaken. The importance of their controversy lies in their contributions to the technique of measurement, the breeding and selection of bees and the influence of their investigations upon further scientific study along similar lines. Previous to this time, Wankler (70) of Germany, had attempted to breed for length of proboscis and had invented and used by 1882 an instrument for determining the length of the bee's tongue. According to Gotze (29), Wankler was the first to show that the bees of different races may differ in the length of their respective proboscides. Likewise, Charton (13), of France, had invented the Charton glossometer in 1892 and by 1897 had presented some figures which seemed to indicate that bees store in proportion to the length of their proboscides. In Russia, scientific workers have recognized the importance of the relation of the honeybee to the pollination of the red clover and have, for many years, made a very extensive study of the length of the proboscis of the honeybee and the relation of honeybees to seed production. The Russian territory is well suited to such a study since hybridization and shipping of bees from one part of the territory to another has practically never occurred. Klingain, according to Michailov (45), in experiments conducted from 1908 to 1913, showed in his first experiment that bumblebees pollinated 49.4% of the flowers in comparison to 45% in the case of Caucasian bees. In his second experiment he found that bumblebees pollinated 46% while the honeybees pollinated 31.1% of the flowers. He further calculated that it would be necessary to have one colony of Caucasian bees per acre of red clover in order to insure proper pollination. Chochlov (14) stated that the minimum average length of the red clover corolla tube was 8.34 mm., that the bees push a part of their heads a distance of 0.65 mm. into the corolla tube, and that the nectar rises in the corolla tube a distance of 1 mm. Thus a bee would have to have a proboscis reach of 6.69 mm. to acquire nectar from red clover. Chochlov also found that the Abkhasian bee and the Kars bee of the Caucasus had a length of proboscis equal to 6.69 mm. The essential part of the work done by Chochlov is his establishing for the first time a technique for preparing the proboscis for measurement. His method consisted of anesthetizing with chloroform, killing in boiling water, boiling in potassium hydroxide solution (KOH) and preserving in oil of cloves after the parts had been washed in water for several days. Ewert (23) conducted a similar investigation of the length of the proboscis in relation to the depth of the corolla tube of red clover and essentially confirmed the results obtained by Chochlov. A more extensive and accurate work on red clover was conducted by Gubin (30), who, contrary to Chochlov and Ewert, showed that the length of the proboscis would have to be from 7.9 mm. to 8.9 mm. in order to reach the nectar in the corolla tube. Since the bees with the greatest length of proboscis were found by Skorikow (63) to be Caucasian bees having a proboscis length of 7.55 mm., Gubin concludes that real red clover bees do not exist in Russia. He also showed that, in using the technique for preparing the proboscis for measurement as set forth by Choclov, the proboscis and other chitinized parts of the skeleton shrink, particularly upon boiling in potassium hydroxide solution, and that the submentum shrinks most (6.31%), the ligula, 3.82% and the mentum only 1.50%. He further showed that by placing the material in a 30% alcohol solution and running it up to a 70% alcohol solution, the shrinkage seldom surpasses 1.5%. Gorbatscheff (28), in 1929, differed with Gubin and claimed the the Caucasian race is the only one which makes use of the nectar of the red clover, but, according to Gotze (29), the material presented by Gorbatscheff is not capable of complete proof. Additional tests in Russia regarding the relation of the honeybee to the pollination of red clover were made by Manokhin and Koorochkin, according to Michailov (45). Manokhin reported an increase of tenfold in the seed production of red clover influenced by the flight of Caucasian bees in comparison with an isolated field. One plot isolated from insects produced only 180 grams of seed per hectare and another produced but 225 grams; while a similar area, located near Caucasian bees, produced 46.4 kg. and another located near black bees produced 32.5 kg. of seed. The test by Koorochkin in 1926 showed that common local bees of Northern Russia produced seed in 0.99% of the flowers, Caucasian bees produced seed in 10.42% and bumblebees produced seed in 27.93%. Free blooming clover showed seed production in 38.93% of the flowers while a plot isolated from insects showed only 0.27% pollinated. |