CONTROLLED MATING IN HONEYBEES 



387 



tions of the experiment have been varied 

 within wide limits. The size of the dose 

 of seminal fluids injected has been varied; 

 some queens have been injected rapidly, 

 and others very slowly; the exposure of 

 the seminal fluids to sunlight, to artificial 

 light, and to heat and cold has been widely 

 varied; some queens have been injected 

 when only seven days old, while others 

 were allowed to attain the age of fifty 

 days before being treated; with some 

 queens the dose consisted of nearly pure 

 sperm with almost no admixture of 

 mucus, with others of a loose mixture of 

 sperms and mucus; sometimes the dose 

 was made to consist of a suspension of 

 semen in normal physiological saline 

 solution, and sometimes of a mixture of 

 semen from several drones all at once. 

 So far these variations of procedure have 

 not led to the uncovering of any certain 

 cue, in either a positive or a negative way. 



DRONES SUSPECTED OF INFERTILITY 



The condition of the problem at the 

 present time casts a glance of suspicion 

 toward the drone. A fund of evidence has 

 accumulated which lightly points to the 

 possibility that partial or complete 

 sterility of the drones may be the variable 

 factor; that motility of the sperms is not 

 a dependable criterion by which to judge 

 of their functional maturity. More and 

 more we find ourselves selecting for labora- 

 tory use the oldest drones obtainable. 

 Furthermore, there is little evidence to 

 warrant the assumption that all the drones 

 that ejaculate when decapitated are func- 

 tionally mature. When we can have 

 them, we prefer drones that ejaculate 

 vigorously when merely seized and gently 

 twirled between the thumb and fingers. 

 Every beginning is a struggle against 

 inertia, but a beginning has been effected, 

 and the problem bristles with genetical 

 and economic possibilities. 



OTHER SCIENTISTS SUCCESSFULLY REPEAT THE 

 EXPERIMENT 



Developments to the present time con- 

 firm the belief that the principle of 

 instrumental insemination is practical as 

 a means of controlling the mating of 

 honeybees. The trend of the technique 

 is in the direction of greater simplicity, 

 the actual operation being somewhat 

 simpler now than was at first thought 

 possible. Several experimenters after 

 witnessing a few demonstrations have 

 been able to take the equipment and 

 inseminate queens for themselves. This 

 fact must not be interpreted to mean that 

 instrumental insemination in its present 

 development is adapted to the immediate 

 use of workers untrained in microscopic 

 technique. In the hands of a micro- 

 scopist, however, the operation is very 

 simple. 



HONEYBEES PROMISE TO BE VALUABLE 

 MATERIAL FOR GENETIC RESEARCH 



Perfect control of mating in honeybees 

 places the new science of honeybee 

 eugenics in the biological curriculum. An 

 attractively large number of the qualities 

 necessary for ideal material upon which to 

 make genetical researches are present in 

 honeybees. The following may be men- 

 tioned: (1) The life cycle is short; three 

 or more generations may be reared in one 

 season, (z) A single mating gives a 

 large amount of progeny. (3) Bees are 

 large enough to permit much scrutiny 

 without the use of microscopes. (4) The 

 present known measurable hereditary 

 characters of bees are not very numerous, 

 yet there is reason to expect that many 

 more such characters will be discovered 

 when bees are more carefully scrutinized. 

 (5) Bees are hardy; they are easily cul- 

 tured, and due to their agricultural rela- 

 tionships, any race betterment achieved 



