6 
PAN-PACIFIC ENTOMOLOGIST 
Comparison with Known Insect Associates of Mycetozoa 
The only available faunal area to compare with these West Coast slime 
mold beetles is Europe. There, as in North America, the best-documented 
association of a beetle taxon with Mycetozoa is for the Sphindidae. Benick 
(1952) lists four species of Sphindus and Aspidophorus from mycetozoans 
of the genera Lycogala and Reticularia (but also, less frequently from a 
few polypore and agaric fungi among the Basidiomycetes). Crowson (1955) 
stated that both British genera {Sphindus, Aspidophorus) “as far as known, 
feed exclusively on Mycetozoa.” 
In contrast, most American authors have characterized the Sphindidae as 
“dry-fungus beetles.” Arnett (1963) for instance, indicates their habitat as 
being “in dry fungi, mostly shelf fungi on tree trunks and old logs.” Aside 
from Hatch’s (1962) record of Odontosphindus clavicornis on the slime 
mold Stemonitis, the only interpretable American host records for sphindids 
are those of Frost (1947) of Sphindus americanus in association with cisid 
species on “small, crowded, woody fungi,” which may be the basidiomy- 
cete Polyporus versicolor or a similar species, and of Odontosphindus den- 
ticollis (LeC.) (as Eurysphindus denticollis) in a “flat, brown fungus of a 
soft smut-like consistency.” The latter description is rather obviously of a 
mycetozoan. The usual occurrence of O. clavicornis in slime molds, and 
my single record of Sphindus crassulus in Fuligo further increase the prob¬ 
ability that this host association is usual, if not exclusive, in the Sphindidae. 
While observations of sphindids apparently feeding on polypore fungi can¬ 
not be completely discounted, they may have been confounded by the fre¬ 
quent occurrence of mycetozoan plasmodia in old polypore sporocarps 
(Martin and Alexopoulos, 1969). The common application of the term “poly¬ 
pore” to almost any dry or woody sporocarp also makes acceptance of such 
records questionable. 
The other genera of beetles reported here from slime molds are also prob¬ 
able mycetozoan specialists. All of the seven species of Anisotoma and six 
species of Enicmus in Benick’s list of European mycophagous beetles have 
been reported from slime molds. In most cases this is the usual or exclusive 
substrate, although Enicmus species are rather often cited from hosts among 
the true Fungi. Benick also reported four of 19 listed species of Agathidium 
from slime molds; the host restrictions in this genus vary at the species 
level. Of the European beetle genera commonly cited from mycetozoan 
hosts, only Amphicyllis (Leiodidae) is missing from my collections; this 
genus does not occur in North America. 
Although I found different species on Fuligo and on Arcyria, there is no 
good evidence of specialization on particular mycetozoan hosts. In part I 
have observed a seasonal effect, for Enicmus and the Sphindidae are evi¬ 
dently adapted to very xeric conditions, while the Leiodidae require more 
moisture, and are (in the Pacific Northwest) more typically active in cool, 
