DEFENSIVE BEHAVIOR OF HONEY BEES 
TOWARD ANTS 1 
By Hayward G. Spangler and Stephen Taber, III 
Entomology Research Division, Agr. Res. Serv., U.S.D.A. 
Tucson, Arizona 85719 
Honey bees ( Apis mellifera L.) often exhibit a unique behavior 
pattern in the presence of ants. We observed this behavior pattern 
and obtained evidence that it is induced by odors from the ants. 
Although the response was not limited to odors known to be pro- 
duced by ants, its primary function is probably a defense against 
them. 
Iridomyrme x is a genus of ants commonly associated with honey 
bee colonies, and the Argentine ant, I. humilis (Mayr), which 
occurs in the southeastern United States and in California, is a 
frequent pest (Newell and Barber, 1913). This ant lays scent trails. 
No alarm pheromone has been identified from it although Blum 
( 1 969 ) reported that one was released by crushing the gaster. 
Newell and Barber (1913) and Wilson and Pavan (1959) reported 
that disturbed workers of I. humilis did not release sufficient quan- 
tities of volatile substances to be detected by human observers, but 
we have detected a faint odor from workers crushed between fingers. 
In contrast, disturbed workers of 1 . pruinosus analis (Andre) emit 
a strong odor which to the human observer resembles 2-heptanone, 
an alarm pheromone isolated from /. pruinosus (Roger) (Blum 
et ah, 1963) and also from the mandibular glands of older honey 
bees (Shearer and Boch, 1965; Boch and Shearer, 1967). 
We studied the response of bees to two species of ants to determine 
whether the defensive behavior of honey bees might be initiated by 
odorous substances and alarm pheromones from an odorous ant 
(/. pruinosus analis) and also by ants which were comparatively 
odor free (/. humilis). 
THE DEFENSIVE BEHAVIOR PATTERN 
Honey bees in a hive frequently were observed being approached 
by ants (/. pruinosus analis) running about on the landing board 
^his work was done in cooperation with the Arizona Agricultural 
Experiment Station. 
Manuscript received hy the editor August 3, 1970 
184 
