cladiinae, none of which was collected above the
effluent. Rio Guacimal midges were hosts to several
new species of Smittium (Fig. 3.27D,E,F). Stachylina
nana (Fig. 3.28C) was also present in the midgut of
the larvae, and on the anal papillae of bloodworms
and blackfly larvae was a new species of Amoebidium
(Amoebidiales; Fig. 3.28D). Amoebidium is the only
trichomycete genus whose species live externally on
their hosts. Five axenic cultures of four Smittium
species were obtained in Monteverde. Other genera
of Harpellales were unculturable.
Other arthropods. Among other dipterans, mos-
quitoes were hosts to several species of Smittium. A
bird bath at Pension Quetzal contained several kinds
of mosquito larvae, including Culexsp. Some larvae
contained Sm. culisetae', others had a new species
of Smittium in their hindguts (Lichtwardt 1994).
Mosquitoes breeding in bromeliads (including Aedes
[Howardina] sp.] were hosts to another undeter-
mined Smittium sp., as was a species of cranefly
(Tipulidae).
In general, streams in Monteverde did not have the
diversity of aquatic insects that occur in high-altitude
streams in North America (Lichtwardt and Williams
1988). Among orders of aquatic insects known to
host trichomycete fungi, stoneflies (Plecoptera) were
noticeably absent in Monteverde studies, as in other
parts of Costa Rica, and mayflies were relatively few.
Ten genera and more than 18 species of tricho-
mycete gut fungi have been found in Monteverde.
Only four were species that are known to be geo-
graphically widespread: Genistellospom homothallica,
Simuliomyces microsporus, Smittium culisetae, and
Stachylina nana. The remainder are currently un-
named species known only from Costa Rican arthro-
pods, and of these a number have been found only in
Monteverde.Acknowledgments The Costa Rican trichomycete
studies were supported by the National Science Foun-
dation (DEB-9220518 and DEB-9521811). I thank the
Tropical Science Center for permission to collect
in the MCFP. I am grateful to those who identified
arthropods: A. J. Shelley and staff of the British Mu-
seum (Natural History) (Simuliidae); Leonard C.
Ferrington, Jr. (Chironomidae) and Paul Liechti
(Ephemeroptera), State Biological Survey of Kansas;
Thomas J. Zavortink, University of San Francisco
(Culicidae); and Dorothy Lindeman, Carleton Uni-
versity, Canada (Amphipoda).Figure 3.27. Trichomycete gut
fungi from the Monteverde region.
A. Small sporulating specimen of
Pennella sp. detached from the
hindgut of a blackfly larva; the
holdfast is the bifurcate basal
structure. B. Fourtrichospores
(asexual reproductive state) of
Genistellospom homothallica that
serve to disseminate the fungus
from one blackfly larva to another.
C. Two biconical zygospores (sexual
state) of G. homothallica as seen
within the larval hindgut.
D. Sporulating branchlets of a
Smittium, one of several species
present in Rio Guacimal midge
larvae. E. Posterior hindgut of a
midge larva totally packed with
Smittium sp. F. Released
trichospores from a pure culture
of the same Smittium sp. Scale
bars = 50 urn for A and E, 20 pm
for B-Dand F.84 Plants and Vegetation