1968] 
West — Polistes exclamans 
121 
press) reports that solitary nest founding also predominates in Kan- 
sas populations of P. exclamans. 
These associated tendencies of P. exclamans foundresses to disperse 
and to move into newly available nesting sites would promote range 
expansion. In contrast, social foundresses tend to remain and re- 
produce near their place of origin. In Polistes fuscatus and P. can- 
adensis , foundress associations are composed of siblings which begin 
new colonies near the parental nest site (West, 1967a), and there 
is indirect evidence that this occurs in other species having social 
nest founding (see Hamilton, 1964; West, 1967a). 
The mode of nest founding of P. exclamans within the newly oc- 
cupied portions of its range is unknown. While most foundresses 
were solitary in the populations of P. exclamans observed in Okla- 
homa, and Kansas (above), the same species commonly exhibits social 
nest founding in Texas (Rau, 1943; Caskey, 1955). Similarly, Rau 
(1942b) found only solitary foundresses in P. fuscatus (— “vari- 
atus ”) in Missouri, whereas in Michigan social nest founding was 
most common in that species (West, 1967a, b). Geographic variation 
in mode of nest founding has also been noted in the European wasp 
P. gallicus (see Hamilton, 1964). Thus, while it has been traditional 
in the literature on social wasps ( e.g ., Wheeler, 1922) to regard 
mode of nest founding as a constant feature of a species, it is prob- 
ably better to consider most Polistes “polyethic” in this respect, with 
mean size of foundress group differing from locality to locality and 
from year to year. Various factors, including parasitization (Eick- 
wort, in press), nest site availability, number of overwintering sib- 
lings, and dominance relations among foundresses, may affect the 
frequency of solitary nest founding and the size of foundress groups 
(see West, 1967a). As the observations of this study suggest, soli- 
tary nest founding might be expected to increase in frequency in 
areas where there is opportunity for (and advantage in) expansion; 
and the ability of some Polistes species to colonize new sites might 
be limited or delayed by selection for social nest founding. 
Acknowledgments 
Distribution data from labels of determined specimens of P. 
exclamans were sent to me by entomologists at the following in- 
stitutions: United States National Museum (A. Menke) ; Univer- 
sity of California, Davis (R. M. Bohart) ; University of Kansas 
(G. W. Byers) ; Kansas State University (H. D. Blocker) ; Illinois 
