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Psyche 
[Vol. 93 
in areas recently invaded by Paravespula. Although perennation 
and polygyny represent significant deviations from the typical Para- 
vespula pattern, the sporadic appearance of such colonies has hin- 
dered study. Published prey studies have addressed only annual 
colonies, thus the discovery of a perennial Paravespula colony at the 
University of California provided an opportunity to study its winter 
diet. 
Materials and Methods 
I first noticed the colony of Paravespula vulgaris (L.) on October 
10, 1984. Typical annual colonies of this native species initiated in 
April or May usually begin to decline in the fall. The high level of 
activity (about 300 worker sorties per minute) indicated that this 
colony had been functional since at least spring 1984, and suggested 
that it might persist for another year. In fact, the colony remained 
vigorous through a second summer, with a final observation of 
external worker activity on February 6, 1986. 
The colony was located about 25 m north of Callaghan Hall ticket 
kiosk on the Berkeley campus of the University of California, at 
elevation 75 m. The immediate surrounding area is a mixed stand of 
Monterey pine ( Pinus radiata D. Don) and coast live oak ( Quercus 
agrifolia Nee) over a grass ground cover dominated by Ehrharta 
erecta Lam. Strawberry Creek, flowing basically east to west, passes 
within 40 meters. 
The subterranean nest was under a fallen log about 1 meter in 
diameter, which supported a lush growth of ivy ( Hedera helix L.). 
Active entrance holes were at ground level on both sides of the log. 
The log was well shaded, although the west entrance received some 
direct afternoon sun. 
To facilitate sampling, I constructed devices to restrict yellow- 
jacket access to the nest at each entrance. To sample from the east 
entrance, I sealed it and netted the returning foragers as they 
hovered near it. After separating prey from the workers by shaking 
the net, I either allowed workers to fly from the net or anaesthetized 
them with carbon dioxide and removed them. A typical 40 minute 
net-sampling session involved approximately 40 sweeps of the net. 
Beginning April 5, 1985, I used a modified funnel trap to collect 
from the west entrance. This passive method was more efficient at 
collecting foragers returning with prey. The trap was left in place 
