28 
Psyche 
[Vol. 87 
of copulations obtained and that individual males were not limited to 
a single mating strategy. At the Boiler site we followed interactions 
between marked individuals daily for 22 days (15 May to 5 June). Of 
51 males marked, 13 were observed an average of7.5 days (5 to 13), 29 
for 1 to 3 days and 9 were marked the last three days of the study. In 
addition to clarifying male mating strategies these data revealed that 
individual males differed greatly in their success in acquiring and 
defending nest territories. 
Usually 5 to 12 males actively competed for territories and matings 
each day. Though the composition of males changed daily as new 
wasps emerged and marked ones disappeared, three males dominated 
our data. These “dominant” males won most encounters and thus 
were rarely forced to abandon a nest territory when challenged. 
Moreover, the “dominant” males quickly abandoned inactive nests 
and patrolled until they located an unguarded or (more likely) a 
guarded nest. Violent, aggressive interactions (Fig. 4) occurred 
between nearly equal size males competing for the same nest. An 
intruding male flew directly at the guard, and a fierce grappling 
match resulted, lasting from several seconds to over one minute. 
Often a series of grappling matches took place before one male 
retreated. “Dominant” males frequently usurped nest territories from 
other guarding males; one male usurped 15 territories in four days. 
Females displayed no obvious behavioral change when new males 
took over their nest territory. We believe that the isolation and 
relatively small size of the Boiler site area (7.6 X 2.4 m) enabled 
individual males to establish and maintain their dominance. One 
male won all encounters over a seven-day period and another male 
was completely dominant over a different four-day period. 
Female Receptivity. Upon eclosion females were sexually recep¬ 
tive, allowing males to copulate for 2 to 3 minutes (x=2.5, n=4), after 
which males dismounted. When mounted a female submitted quickly 
by raising her gaster, allowing copulation. Newly emerged females 
required a few days to develop mature eggs (dissections of newly 
eclosed wasps revealed small, clear eggs beginning to develop in the 
ovarioles). These females spent considerable time investigating the 
nesting area and were therefore easy targets for patrolling males. 
Once nesting began, females tended to avoid males when digging or 
provisioning. When intercepted, females varied in their response; 
some allowed a male to mate on most trips to the nest without 
