﻿26 BULLETIN 1364, tJ. S. DEPARTMENT OF AGBlCULTTJRE 



According to these figures, it appears that 0.0005 milligram of 

 metallic arsenic is a conservative quantity to represent the minimum 

 lethal dose Der bee. Some of these results have already been pub- 

 lished U,pp. 28,Jf8), 



In these experiments the behavior of the poisoned bees was care- 

 fully observed to determine whether it was similar to that of bees 

 poisoned by arsenic in the fields. On the second day after having 

 been poisoned many of these bees became more or less inactive and a 

 few clied ; after that most of them were seldom seen eating ; by the 

 third day they were dying rapidly, their abdomens were much 

 swollen, they could not fly, but could yet walk in a staggering man- 

 ner, dragging their abdomens on the table. The visible effects of 

 arsenic poisoning on them were similar to those of nicotine poisoning 

 on bees already described by Mclncloo {9, pp. 91-92), except that 

 nicotine acts the more quickly, and its symptoms are the more pro- 

 nounced, also that in cases of arsenic poisoning the abdomens are 

 always more or less swollen, while this effect is rarely observed in 

 cases of nicotine poisoning. Judging from the symptoms observed, 

 bees fed arsenic seem to die of motor paralysis, although the paraly- 

 sis may be only a secondary cause. 



DISCUSSION OF LITERATURE 



Only one of the many reports of the experiences of beekeepers will 

 be cited here. This one, presented by Felt (6), states that several 

 men sprayed their fruit trees with arsenicals while in full bloom. 

 May 18 and 19, 1900. The first dead bees were observed on May 20, 

 One beekeeper says: 



In front of each hive lay the full working force of the bees, some in clusters 

 apparently dormant and others wriggling about as if in great agony. With 

 the appearance of the sun there was a general movement among the bees in 

 an effort to get as far away from the hive as possible. Those that had the 

 strength would try to fly, but could only succeed in making 3 or 4 feet before 

 they would drop to the ground. 



The next day. May 21, a few hives were opened. Practically all 

 of the field bees were gone, but a large quantity of brood and a few 

 young bees were left. This beekeeper claims to have lost his entire 

 apiary of 100 colonies, valued at $500. 



According to the same report, another beekeeper claims to have 

 lost between 80 and 95 per cent of the workers in his apiary of 95 

 colonies. Orchards were sprayed while in full bloom, 1^/2 miles north 

 and the same distance northwest of a third beekeeper's apiary of 

 200 colonies, May 21 and 22. May 23, handfuls of dead and dying 

 bees lay near the hives. 



The following scientists have carried on experiments to determine 

 the effects of arsenic on bees. 



Brose {!) mixed London purple and Paris green in sirups in the 

 same proportions in which these two insecticides are mixed with 

 water for spray materials. When these poisoned sirups were fed 

 to bees, they were not eagerly eaten. Some of the bees tested died 30 

 minutes after taking the poison, while others lived 4 hours. The 

 chemical analyses of the sirups stored in the combs did not show 

 arsenic, but traces of it were found in the bees killed by eating the 

 sirups. 



