55°. Journal of Agriculture, Victoria. [lo Aug., 191 i. 



DYSENTERY IX BEES AND NOSEMA APIS. 



F. R. Beuhne, Bee Expert. 



Since the publication of the articles on Bee Mortality in the Journal 

 for January, 19 10, which reported the presence in Victorian bees of the 

 Nosefna parasite discovered by Dr. Zander, bee-keepers have looked upon 

 this parasite as a serious menace to the bee-keeping industry. I refer to 

 those bee-keepers who assumed that the abnormal losses of bees in the 

 Grampians country in the spring of 1909 were caused by Nosema apis. 



The microscopical examinations of bees from all parts of Victoria, 

 made by Mr. W. Laidlaw, B.Sc, Biologist of the Department of Agri- 

 culture, during the past twehe months, show that Nosema apis is present 

 in some bees in nearly every apiary, even in localities where losses have 

 never occurred, and where colonies are in a prosperous and highly pro- 

 ductive condition. 



This reassuring outlook is further strengthened by an article in the 

 Miinchener Bienen Zeitung of May, 191 1, by Dr. Walter Hein, of the 

 Biological Experiment Station at Munich. After recapitulating Dr. 

 Zander's theory of Nosema apis. Dr. Hein says : — 



Dr. Zander's theory created much stir; and, in view of the far-reaching con- 

 sequences which he indicated as being proved b\' observations and experiments, it 

 appears desirable to review the Nosema question in the light of scientific observa- 

 tions and experiments made by others. 



In March, 1910, Dr. A. Maas.sen, of the Imperial Biological Institute, 

 published the following results of some interesting experiments : — 



A colony of bees experimentally infected did not show Nosema spores in the 

 excrements voided a fortnight later, and only a month later was the parasite 

 found in the chyle stomach of the bees, and still later in the excreta. 



Two other experimental stocks appeared quite healthy four weeks after in- 

 fection. In six weeks, parasites were observed ; and, even after eight weeks, 

 there were no distinct symptoms of dysentery, although by now the parasite could 

 be found in mosjt of the bees. One of these colonies did not show any symptoms 

 till three months had passed. 



Dr. Maassen states that it is probable that the Nosema parasite will 

 be found in limited numbers in bees without causing a noticeable inter- 

 ference with the health of the colonies, and that Nosema onlv becomes 

 dangerous when adverse conditions lower the vitality of the bees. 



In a publication of more recent date (March, 191 1) Dr. Maassen gives 

 the results of later experiments which in many respects contradict those 

 of Dr. Zander. 



The distribution of Nosema apis is so great that there are perhaps only a few 

 apiaries in Germany where all colonies are absolutely c'ean. Even in only mildly 

 affected colonies, odd bees contained the parasite in enormous numbers. Badly 

 infected bees live remarkably long and remain active. 



In autumn, 1909, Dr. Maassen wintered thirty colonies which showed 

 a high degree of infection. In spring, three of the colonies showed 

 symptoms of dysentery ; two, hea^•y losses in bees ; and one had died of 

 starvation. The remaining stocks wintered well and built up normally, 

 while even those with symptoms recovered. In all the colonies the parasite 

 could always easily be found. In some of the hives " May Sickness " 

 suddenly appeared without, however, doing much injury to them. The 

 bees examined showed enormous numbers of Nosema spores, but even 

 these colonies recovered and behaved exactly the same as perfectly healthy 



