1983] 
Rissing — Pogonomyrmex colei 
325 
Table 1. Summary of mating activities of P. colei and P. rugosus in Boulder City, 
Nevada, 15 September 1978. 
Time 
Ground 
Air 
08:55 
Temp. °C 
Temp. °C2 
09:10 
20.5 
20.5 
09:37 
10:03 
21.0 
21.5 
10:45 
26.0 
23.8 
12:15 
29.2 
25.5 
12:47 
32.6 
26.4 
13:15 
33.4 
30.8 
Activity 
Reproductives of both species in nest 
entrance 
P. colei reproductives on crater 
Number of P. colei increases 
First P. colei copulation 
First P. colei female flies 
Last P. colei female flies 
First P. rugosus male and female fly 
Last P. rugosus flies 
'Temperature as determined by holding tip of a Yellow Springs Instruments direct 
read thermistor (YSI #405) on ground surface; temperature read on a Yellow Springs 
Instruments telethermometer (YSI #43TA). 
^Temperature determined as above with thermistor 30 cm above ground and shaded. 
group size in 1982, the host queen must have been alive during the 
1978 and 1979 inquiline flights. Although inquiline-host coexistence 
has been regarded as a “primitive” inquiline trait (Wheeler 1933, 
Haskins and Haskins 1964), it offers the obviously adaptive advan- 
tage of a continuously renewed host worker force for the inquiline. 
Coexistence occurred in the type nest of P. colei and appears 
common in other workerless inquiline species where information 
regarding fate of host queen(s) is available (Table 2). 
Host queen elimination does occur in at least two well docu- 
mented cases (Table 2). Wilson (1971) suggests such behavior may 
develop in short-lived inquiline species; inquiline longevity, how- 
ever, may be more of an effect than a cause of this behavior. Host 
queen elimination may be adaptive only when inquiline entry is 
gained by a queen after development of a host worker force. Host 
workers appear to be the primary defense against inquiline entry in 
many colonies. In order to be accepted by host workers, it may be 
necessary for the prospective inquiline queen to first render the 
prospective host colony queenless. In those cases where host queens 
are known or highly suspected of being eliminated (Table 2), the 
inquiline queen enters an established colony containing workers. In 
at least one of these cases, Epimyrma vandeli, the inquiline must 
fight with host workers until she is able to kill the host queen. 
Recent discovery that E. vandeli is a degenerate slave-maker 
