32 CIRCULAR 3 9 2, U. S. DEPARTMENT OP AGRICULTURE 



largely prevented, however, by providing' good wintering conditions 

 for the bees. 



SYMPTOMS 



The first noticeable symptoms are restlessness and weakness. 

 Weakness increases until death occurs. A few sick bees may die 

 in or near the hive, but they usually fly or crawl from the hive and 

 seem intent upon getting as far away as possible before they die. For 

 this reason mycosis of adult bees is likely to be overlooked, particu- 

 larly when only a few bees at a time are affected. 



By pressing the abdomen between the fingers, an increased firmness 

 can sometimes be noticed at the time of death, but it is most notice- 

 able a few hours later. It is unsafe to depend upon this symptom 

 longer than about 1 or 2 days after death, since nonpathogenic fungi 

 may produce similar symptoms in bees killed by other disorders. 



"PARALYSIS" 



CAUSE 



The so-called paralysis of adult honeybees appears to be a slightly 

 infectious disease that causes weakness, trembling, and death of the 

 affected bees. The causei of paralysis has not been definitely deter- 

 mined, although various theories regarding the cause have been 

 advanced from time to time. Recent work at the Government Bee 

 Culture Laboratory indicates that paralysis is infectious. 



IMPORTANCE 



Paralysis of honeybees is a widely distributed disorder, but it 

 causes greater losses in warm than in cold climates. Affected 

 colonies usually recover after a short time, but in some cases the 

 disorder continues throughout the season. In the Northern States it 

 usually disappears or remains confined to one or a few colonies 

 within .an apiary, but in the South it sometimes spreads and causes 

 considerable loss. The losses range from a few bees in mild cases to 

 most of the bees of the affected colonies in malignant cases. 



SYMPTOMS 



Owing to the fact that the appearance of the sick and dead bees 

 is not always the same, there seems to be a difference of opinion 

 regarding the symptoms of paralysis. Other disturbances of adult 

 bees may also have been mistaken for paralysis. 



During the early stages of paralysis, affected bees remain on the 

 combs and cannot be distinguished readily, except that the healthy 

 bees often tug and pull at them excitedly. The sick bees make but 

 little effort to defend themselves. Sometimes they offer food or 

 attempt to escape by crawling away. Finally, they leave the hive 

 and die outside or crawl into a comer of the hive or onto the top 

 bars, where they remain until death occurs or until they are carried 

 out of the hive by the healthy bees. Some affected bees die within 

 a day or two after the symptoms have become noticeable, others 

 linger for more than a week, while still others recover. The abdo- 



