PSYCHE 
Vol. 83 
June, 1976 
THE SOCIAL ORGANIZATION OF MALE 
POPULATIONS OF CENTRIS PALLIDA 
(HYMENOPTERA, ANTHOPHORIDAE)* 
By John Alcock 
Dept, of Zoology, Arizona State University, Tempe, AZ 85281 
This report is one in a series of papers on the reproductive 
behavior of the solitary bee Centris pallida Fox. Elsewhere we 
have shown that males of this species exhibit a behavioral di- 
morphism in mate-location strategies, with some males flying 
low over the ground searching for virgin females about to emerge 
and other males hovering around the borders of emergence sites 
as well as by flowering trees (Alcock et al., 1976; in press). The 
patrollers excavate virgin females from their emergence tunnels 
and then copulate with them; hoverers secure mates by pursuing 
air-borne virgins which they capture in flight. 
Our earlier studies left unanswered several questions about 
the spatial organization of male populations of this bee, including 
1) Do patrolling males exhibit loyalty to a particular portion 
of an emergence site and if so, for how many days? 
2) How much area do patrollers examine? 
3) Do males that hover remain at a particular aerial station 
for any length of time? 
Almost nothing is known of the behavior of male solitary Hymen- 
optera with respect to the size of the territory or home range of 
individuals and the duration of time males spend on a territory 
or home range (Alcock et al., in prep.). After following a large 
sample of marked bees from the start of the emergence season to 
its conclusion, I am able to provide information on the social 
structure of male populations of C. pallida, especially with refer- 
ence to the degree of site tenacity and degree of territoriality shown 
by hovering and patrolling males. 
* Manuscript received by the editor October 4, 1976 
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