1986] Gambino — Winter prey of Paravespula 333 
approximately 15 minutes per sampling session. Captured workers 
were anaesthetized and shaken from the trap. Anaesthetized 
workers were returned to the vicinity of the nest entrance for which 
they had been bound. Items separated from the workers were 
immediately transferred to 70% EtOH. 
I identified sorted samples to lowest feasible taxonomic levels 
with the assistance of workers at the Essig Museum, University of 
California, Berkeley. An item which was recognizable as a single 
prey load was counted even if it was only a fragment of an organism. 
For example, a honeybee abdomen counted as one record of Apis 
mellifera L. 
I visited the colony to observe wasp behavior daily from January 
5 to May 10, 1985, and sampled approximately weekly. Time of day 
and environmental conditions during sampling varied somewhat, 
but most sessions were during the early to mid afternoon of bright 
sunny days. 
Results 
I analyzed a total of 1306 items, many of which were only frag- 
ments and/or badly mauled. Precision of identification was variable 
. Thus, while some relatively intact prey items could be identified to 
species, other more macerated fragments of arthropods could not be 
identified below phylum. Because there is no way to know which 
items were captured live (predation sens, str .) and which were scav- 
enged, I classified all food items as prey. No items of food made or 
prepared by humans were identified. 
The 914 prey items that could be identified at least to order are 
summarized in Table 1 according to taxa and collection dates. 1 
Temporal variation of selected prey items in the colony’s diet, illus- 
trated in Figure 1, reflects the sequential availability of potential 
prey species, based on their life history patterns. 
I began the study during the flight period of the sawfly, Xyela 
radiatae Burdick, when adults were so abundant that they actually 
crawled into my net during several collection sessions. Accordingly, 
X. radiatae was the dominant prey item in January (79% of deter- 
mined specimens). Yellowjackets commonly hunted in the short 
'A more detailed list of prey is available from the author on request. 
