128 
Psyche 
[June 
optera as the oaxaeid bee Protoxaea gloriosa (Cazier & Linsley, 
1963; Linsley & Cazier, 1972; Alcock, pers. obs.) and a number 
of philanthine wasps (Alcock, 1975). The question arises for all 
these species, why should a male remain in an area for a period 
of hours, holding the site exclusively, only to abandon it com- 
pletely, taking up residence at distant sites on subsequent days? 
The key to this problem may lie in the very low frequency of 
mating by the hovering/ perched males mentioned above. Judging 
from the extreme rarity of observed copulations, a waiting male 
in these species has almost no chance of encountering a receptive 
female, no matter where he chooses to hover or to perch. Thus 
the value of a vast array of potential waiting sites must be nearly 
equivalent (i.e. close to zero). Given the equivalence of many sites 
it is not surprising that males often shift their hovering/ perching 
sites from day to day (probaby selecting an unoccupied suitable 
location that happens to be near the male at the moment). Shift- 
ing would also be promoted by a “musical chairs effect”. If there 
are many males present, it is likely that a bee would find his old 
waiting site taken when he arrived to reclaim it on the following 
day. It may not pay to fight over an occupied site if there are many 
other equally good unoccupied places nearby. The result would 
be continual shifting of males as they avoided one another, taking 
whatever hovering/ waiting site that happened to be open to them. 
When conspecifics are rare, hoverers might be expected to show 
more site tenacity because they would be less likely to find their 
previous day’s hovering station occupied when they reached it on 
the next day. At Study Site 2, there were very few hoverers present 
and these appeared in the same aerial stations several days run- 
ning. A male that has claimed a site might defend it to avoid the 
time costs of shifting to a new one and because it costs so little to 
defend it. A new arrival, finding the site taken, would have very 
little motivation to contest ownership because of the abundance 
of equally good waiting locations nearby. 
In contrast to the weak territoriality and low site tenacity shown 
by hovering C. pallida, males of this species and others that patrol 
emergence areas ignore one another when searching the emergence 
site, yet show a stronger site attachment than hoverers. The per- 
sistence of home ranges in patrolling C. pallida almost certainly 
stems from the clumped nature of the resource, emerging virgin 
