1986 ] Gambino — Winter prey of Paravespula 337 
grass near the colony, especially beneath Pinus radiata , the xyelid’s 
host plant (Burdick, 1961). Workers flying close to the ground thor- 
oughly scanned plant surfaces, paying special attention to areas of 
contrasting colors and textures to locate and capture surface- 
inhabiting arthropods, which comprised the vast majority of the 
colony’s prey. I observed attempted and successful captures of X. 
radiatae adults on grass blades. These sawflies, presumably newly 
emerged from underground pupae, seemed especially vulnerable to 
Paravespula predation. 
In late February, the beetle, Byturellus grisescens (Jayne), 
reached its greatest abundance in the prey samples. Although I was 
unable to capture any of these beetles myself, they oviposit on oak 
catkins (J. Doyen, pers. comm.). This was the first good suggestion 
of the importance of oak insects in the diet of the colony. Of the 
many tree species occurring on the University campus, Q. agrifolia, 
a native, is one of the most common. 
As the season progressed, hunting at ground level became less 
frequent, and foragers shifted their attention to tree foliage, particu- 
larly Q. agrifolia . Local population explosions of caterpillars (Lepi- 
doptera) in late March and April, and the treehopper, Cyrtolobus 
vanduzeei Goding, in May were also tracked by this colony (Fig. 1). 
Again, most of the identifiable Lepidoptera and Membracidae were 
of taxa known to be associated with Q. agrifolia. 
Discussion 
The wide taxonomic array of arthropod prey and focus on 
abundant prey species shown by the observation colony are consist- 
ent with known habits of the genus Paravespula. Scavenging, a 
characteristic of the genus, is suspected in the collection of pieces of 
earthworm and Apis mellifera, as well as some other items which 
were tangled in silk strands and may have been taken from spider 
webs. Collection of proteinaceous food prepared for human con- 
sumption, a habit accounting for the pest status of P. vulgaris in 
many areas (MacDonald et al., 1976) was not detected. Although 
such food was certainly within the flight range of foraging workers, 
it was not common in the immediate vicinity of the colony, and 
foragers may have become conditioned to locate arthropod prey. In 
general, the data from the observation colony indicate that the flesh 
