1919 



AMERICAN BEE JOURNAL 



261 



the infection persists for a short pe- 

 riod only, the weakness resulting 

 passes unobserved. The loss in 

 strength is more often gradual, but 

 may be quite sudden. 



The diseased bee, as to its outward 

 appearance and general behavior, is 

 not particularly unlike the healthy 

 one. The infected workers carry 

 pollen, honey and water, and at the 

 entrance of the hive cannot be dis- 

 tinguished from healthy ones. It was 

 found, from experiments carried on 

 during the fall and early winter, that 

 the cluster of heavily-infected colo- 

 nies was easily disturbed, and when 

 disturbed, the bees ran badly. 



As a rule, the stores in a Nosema- 

 diseased colony are sufficient. The 

 queen does her work well, and when 

 the colony dwindles and dies out she 

 is usually to be found among the last 

 handful of bees. The brood is nor- 

 mal in appearance, but is frequently 

 in excess of the amount that can be 

 comfortably cared for. 



Sooner or later the stomach of the 

 diseased bee invariably furnishes 

 positive evidence of the presence of 

 the disease. Usually by the end of 

 the second week, following the infec- 

 tion, the organ becomes lighter in 

 color. It is also somewhat larger, 

 softer and more easily torn. Late in 

 the disease its size is about' that of 

 the healthy stomach and it is almost 

 white. This colony symptom is the 

 most valuable of all and furnishes 

 positive evidence of the presence of 

 Nosema-disease. 



The spotting which characterizes 

 dysentery is absent, and the trem- 

 bling that is frequently described for 

 one. or possibly more, abnormal con- 

 ditions of bees, is not a noticeable 

 symptom of the disease. While not 

 infrequently there are more dead bees 

 on the ground in front of a hive hous- 

 ing a Nosema-diseased colony than a 

 healthy one, a heap of bees, such as 

 is so often found in front of hives 



where paralysis is present, seldom, if 

 ever, occurs in Nosema-disease. In 

 experiments conducted in the fall 

 and early winter, more dead bees 

 were found on the bottom-board, in 

 case of inoculated colonies than un- 

 inoculated ones. The crawling and 

 climbing tendency of bees, described 

 as symptoms in some bee troubles, 

 does not characterize Nosema-disease. 

 Adult Workers, Drones and Queens 



Susceptible to Nosema Infection 



After a colony, free from the dis- 

 ease, has been fed syrup to which the 

 parasite (Nosema apis) has been 

 added all, or practicalh' all, of the 

 workers of the colony become in- 

 fected. When there are drones, in 

 the colony, they also become infected 

 in a somewhat similar proportion. 

 When queens from such colonies are 

 examined they, too, are sometimes 

 found to be infected, but frequently 

 they are not. From observations thus 

 far made, infected queens are less 

 likely to be encountered during the 

 active brood-rearing season than at 

 other times of the year. In the ex- 

 perience of the writer, no Nosema- 

 infected drones were found except 

 in colonies in which the disease was 

 produced by artificial inoculation. It 

 is interesting, also that the old, shiny 

 bees in nature were not found in- 

 fected. That they are susceptible, 

 however, to infection, was demon- 

 strated, as was done in the case of 

 drones, by experimental inoculation. 

 Brood Not Susceptible to Nosema- 

 Infection 



Studies were made of the brood in 

 experimentally infected colonies, and 

 in no instance were infected larvae 

 found, either worker, drone or queen. 

 The pupae, likewise, upon examina- 

 tion, were always found to be healthy. 

 Young bees emerging from the brood- 

 comb were invariably free from infec- 

 tion. 

 Length of Time an Infected Bee Lives 



It is not known positively whether 



M I I V\ ard grafting cells 



a Nosema-diseased bee ever recov- 

 ers from the disease. Some of the 

 observations suggest that now and 

 then a worker recovers from the in- 

 fection. If this ever occurs, it is de- 

 cidedly the exception, for they usu- 

 ally die. It should be emphasized 

 here, that a bee does not die of the 

 disease soon after becoming infected, 

 but lives for a relatively long period. 

 As the length of life of healthy 

 queens, workers and drones, respec- 

 tively, is different, so it is to be ex- 

 pected that the period of life of in- 

 fected ones will also be different. In- 

 fected queens will probably live 

 longer than infected workers and in- 

 fected workers will live longer than 

 infected drones. That the age of the 

 bee at the time of infection will de- 

 termine to a certain extent the period 

 it will live, is evident from the nature 

 of the disease. That the season at 

 which infection takes place has much 

 to do with the period a worker in- 

 fected with Nosema apis will live is 

 also evident from the nature of the 

 disorder. Infected during the more 

 active bee season, a worker will live 

 longer, other things being equal, than 

 if infected during some less active 

 season. During the winter season, at 

 least, the strength of the colony to 

 which an infected worker belongs, 

 and the percentage of diseased bees 

 present, probably have something to 

 do with the period the worker will 

 1 i >- e . Observation made on medium- 

 sized colonies, inoculated late in the 

 fall, showed that most of the work- 

 ers live more than 2 months, but less 

 than 3. During the summer most of 

 the infected ones die in less than one 

 month. 



There is considerable evidence to 

 indicate that queens are not as read- 

 ily infected as are the workers. This 

 seems to be true especially during the 

 more active season. Among the 

 queens taken during the active sea- 

 son, from experimental colonies in 

 which a heavy infection among the 

 workers had been produced, as the re- 

 sult of inoculation, rarely have in- 

 fected ones been found. There is 

 some evidence, also, that queens, un- 

 der favorable circumstances, may re- 

 cover from Nosema-infection. A 

 careful microscopic study of queens 

 from infected colonies, made during 

 the less active season, showed some 

 free from infection, others heavily 

 infected, and still others with only a 

 slight amount of infection. 



It will be seen that the question, 

 relative to the period an infected bee 

 lives, is dependent upon many factors 

 and that considerable data must yet 

 be obtained before statements of a 

 more definite character can be made. 



Length of Time the Germ Lives 



After the germ of Nosema-disease 

 is voided from the alimentary tract it 

 invariably dies unless it is taken up 

 by some other bee. The same is true 

 of the germs in the body of bees that 

 die of the disease. They do not die 

 immediately, however, but live a vari- 

 able length of time, depending upon 

 the environmental condition. The 

 question relative to the period the 

 parasite will live when subjected to 

 heat, drying, sunlight, fermentation, 

 putrefaction and freezing, respec- 



