196 



June, 1916. 



American l^ae Journal 



than 5500 bees were used in their nor- 

 mal state. Foods fed to them contained 

 repellents and those having the four 

 attributes of human taste : sweet, bit- 

 ter, sour, and salty. The following 

 substances are the most important 

 ones used: carbolic acid, oil of pepper- 

 mint, whiskey, various acids, formalde- 

 hyde, kerosene, lime-sulphur, seven dif- 

 ferent kinds of sugars, quinine, strych- 

 nine, lemon juice, and 11 different salts, 

 including our common table salt. Some 

 of these substances were mixed with 

 honey, others were mixed with cane- 

 sugar, while the various sugars were 

 made into candies. Cane-sugar candy, 

 three varieties of honey, sugar syrup 

 honey and pollen mixed, and honey 

 and sugar mixed, not containing any 

 of the above substances, were also fed 

 to bees. 



It was found that bees generally avoid 

 foods containing repellents unless they 

 are forced to eat them when the pure 

 foods are removed. In such cases the 

 bees show preferences between the 

 foods containing the various repellents. 

 They are fond of their favorite food 

 flavored with whiskey, but they do not 

 like it as well as pure honey. 



Bees show decided preferences be- 

 tween candies made of various sugars. 

 They cannot be forced to eat saccha- 

 rine (a sugar 50(t times as sweet as cane 

 sugar) candy, but greedily eat manose 

 (a simple sugar) candy which kills 

 them as quickly as strychnine. They 

 are particularly fond of cane-sugar, 

 levulose (fruit sugar) and maltose (malt 

 sugar) candies, but care little for dex- 

 trine (a starch gum and not a sugar) 

 and lactose (milk sugar) candies. 

 They care little for raflinose (a sugar 

 from a certain Australian eucalyptus 

 plant) candy when they have the pref- 

 erence of cane-sugar, levulose or mal- 

 tose candy, but much prefer it to dex- 

 trose (grape sugar) candy. Bees can 

 be forced to eat any of these candies, 

 except saccharine, when no other food 

 is present, but these experiments were 

 not aimed to determine what candies 

 agree with them best. Of these can- 

 dies, they like cane-sugar candy best, 

 although levulose candy is a close 

 second. 



The bees liked fresh basswood honey 

 much better than an old dark-colored 

 honey given to them. The source of 

 the latter honey was unknown. It was 

 taken in the crystallized form from old 

 combs and was then melted. They 

 care little for either sugar syrup (half 

 and half), or for basswood honey and 

 pollen (4 parts honey to 1 part pollen), 

 or for basswood honey and sugar (half 

 and half) when they are given pure 

 basswood honey at the same time. 



In these experiments bees also 

 showed marked preferences between 

 foods containing bitter and sour sub- 

 stances and between the foods contain- 

 ing the various salts. They could 

 scarcely be forced to eat chinquapin 

 honey, and in a few instances showed 

 decided preferences between certain 

 foods while the writer could detect 

 only little or no differences between 

 the same foods. 



The preceding results clearly dem- 

 onstrate that bees have likes and 

 dislikes in regard to foods and can dis- 

 criminate between some foods better 

 than we can. As a general rule, foods 

 agreeable to us are also agreeable to 



bees, but there are a few marked ex- 

 ceptions. Substitutes for honey as 

 food for bees may be better than honey 

 in a few instances, but these investiga- 

 tions show that no substitute can be 

 had which will be liked by them as well 

 as the best pure honey. 



That bees must first eat more or less 

 of the foods before being able to dis- 

 criminate differences between them, 

 unless they contain repellents, indi- 

 cates that bees have a sense of taste, 

 provided this discrimination is not ac- 

 complished by means of the sense of 

 smell. This point was decided after 

 making a study of all the sense organs 

 on and near the mouth-parts. Only 

 two types of sense organs were found. 

 The organs of smell, already briefly 

 discussed, make up the first type. 

 These cannot be used as taste organs 

 because they rarely, and perhaps never, 

 come in contact with the liquid food 

 being eaten. Sense hairs form the sec- 

 ond type. These also cannot serve as 

 taste organs because the liquid foods 

 cannot pass through their walls in 

 order to stimulate the nerves attached 

 to them. 



Since bees are covered with a hard 

 outside coat, they cannot feel weak 

 pressures, and for this reason certain 

 hairs have become connected with 

 nerves. Nearly all the hairs on the 

 mouth-parts are connected with nerves. 

 The tongue is quite sensitive to touch, 

 because it has about 85 sense hairs, 

 which lie among the dead hairs so 

 easily seen on this appendage. These 

 long hairs are not true hairs and are 

 not connected with nerves. The man- 

 dibles or "jaws" are literally covered 

 with sense hairs and organs of smell. 

 These hairs are irregularly scattered, 

 except there is a curved row at the tip 

 of each mandible on the outer side. The 

 hairs in this row curve slightly over 

 the edge of the mandible toward the 

 biting surface or inner side. These 

 hairs may be roughly compared to the 

 fingers at the tips of the trunks of 

 elephants, although they are certainly 

 many, many times as sensitive. In fact, 

 the tips of the most sensitive human 

 fingers imaginable cannot be compared 

 in sensitiveness to the mouth-parts of 

 a worker-bee. Such a keen sense of 

 touch easily explains how workers can 

 handle the eggs and larva; without in- 

 juring them, and why they are able to 

 mold the walls of their cells of a uni- 

 form thickness. The sense hairs of 

 the mouth-parts and also those on the 

 antennae enable the bees to communi- 

 cate with each other merely by touch. 



There are a few sense hairs in the 

 -cavity leading to the mouth, and the 

 fleshy three-lobed "tongue "-hanging in 

 front of the mouth bears two large 

 groups of sense hairs. In the mouth, 

 just in front of the pharynx, there are 

 two more large groups of sense hairs. 



All over the head, on the throat, on 

 the legs and even on the body of t-he 

 bee, there are sense hairs so located 

 that it is impossible for a person to 

 touch a bee without touching some of 

 these hairs. 



We are now ready to explain how 

 bees eat solid and liquid foods. By 

 means of sense hairs on the mandibles, 

 these appendages can separate the pol- 

 len or bee-bread into pieces small 

 enough to be swallowed. These pieces 



are then dropped upon the extreme 

 base of the tongue which resembles a 

 small crane in that it may be moved up 

 and down, backward and forward and 

 from side to side. The upward move- 

 ment carries the pollen to the mouth, 

 where it is pushed into the mouth by 

 means of the fleshy "tongue " covered 

 with sense hairs already mentioned. 

 Should a piece of pollen be too large to 

 pass through the esophagus, it could 

 not pass between the two groups of 

 sense hairs just in front of the pharynx 

 without touching them. In such a case 

 these hairs would cause the muscles 

 attached to the sides of the mouth to 

 contract whereby the pollen would be 

 thrown to the exterior. It is thus seen 

 that these sense hairs serve as a safety 

 device to prevent the bee from swal- 

 lowing pieces of solid food too large 

 to pass through the esophagus. 



When a bee smells food it at once 

 extends its tongue and touches the 

 food. The sense hairs at the tip of the 

 tongue inform the bee as to whether 

 the food is liquid or solid. If liquid, it 

 is immediately eaten. But suppose it 

 is candy containing an undesirable sub- 

 stance which the bee cannot detect 

 until the candy is dissolved. At once a 

 small current of saliva passes through 

 the canal in the center of the tongue to 

 the tip of this appendage. As soon as 

 the saliva mixes with the food, a chemi- 

 cal or physical change is brought 

 about, and this change perhaps liber- 

 ates odors that were not smelled by 

 the bee before the food was eaten. The 

 dissolved food now passes through the 

 deep groove on the underside of the 

 tongue merely by capillary attraction. 

 Since the organs of smell on the 

 mouth-parts are almost in contact with 

 this food as it passes from the under- 

 side to the upper side around the base 

 of the tongue, the faintest odor imagin- 

 able from the undesirable substance 

 could be detected by these organs. 



This is why the writer claims that 

 the bee has a combined sense of smell 

 and taste, although it is easily seen that 

 the sense of taste really plays no part 

 in the reactions shown by bees while 

 eating. To us sometimes a food, before 

 being eaten, emits only a faint odor or 

 no odor at all; but when we eat it, we 

 perceive a pronounced odor. In such 

 a case the odorous particles are not 

 given off until the food is taken into 

 the mouth and mixed with saliva. The 

 same principle is certainly applicable 

 when bees eat candies which contain 

 undesirable substances emitting ex- 

 tremely weak odors. The liquid food 

 now lying on the upper side of the 

 tongue is raised to the mouth opening 

 where it is sucked into the mouth by 

 means of the pharynx acting as a pow- 

 erful pump. The pharynx is able to do 

 this because it is supplied with several 

 large muscles. 



The preceding closes the summary of 

 the writer's published bulletins pertain- 

 ing to the senses of smell, taste and 

 touch. Since the writer is no longer 

 connected with the office of bee-culture 

 and perhaps will never study the senses 

 of the honeybee any more, a few re- 

 marks about the uses of the sense of 

 smell and about the other senses of 

 this insect may not be out of place here. 



Washington, D. C. 



[Concluded in July number.] 



