web in leaf litter near trunks or roots, but in primary
forest it expands its vertical distribution to epiphytes
on vertical trunks. Cyclosa constructs its web in rela-
tively protected places such as vertical trunks, small
plants, and shrubs. Micrathena pilaton and Chryso-
meta otavalo place their webs in open places, such
as between two shrubs or small plants; the latter spe-
cies has a similar vertical distribution in clearings. All
of these species except Azilia were more abundant in
primary forest. Chrysometa near opulenta, C. near
globosa, and C. near saladito (Tetragnathidae) oc-
curred mainly in primary forest, perhaps due to the
greater abundance of large leaves, as they construct
their webs under such leaves. The small spiders
Anapidae sp. 1 and Symphytognathidae sp. were also
more abundant in primary forest. Naatlo sutila
(Theridiosomatidae) constructed its webs principally
in open spaces, which are more common in second-
ary than in primary forest. Uloborus trilineatus (Ulo-
boridae) and Epeirotypus sp. (Theridiosomatidae)
constructed webs on vertical trunks, the latter pre-
ferring secluded places. Theridiosoma sp. (Theridio-
somatidae) used shrubs in primary forests and verti-
cal trunks in secondary forest. Chrysometa n. sp.
(Tetragnathidae) generally constructed its webs be-
neath branches or large leaves. Leucauge sp. 1 (Tetra-
gnathidae) was exceptional in that it was observed
only in natural clearings where their webs occur in
the upper parts of the vegetation and in abandoned
pastures (Fig. 4.19).
Nearly 3000 insects were captured in sticky traps
and identified. The largest number of captures was in
the secondary forest, followed by natural clearings.
In all three habitats, the highest percentage of insects
was captured near the ground. In primary forest, the
percentage decreased from level 1 (0-0.3 m) to level
2 (1-1.3 m) but showed a slight progressive increase
at higher levels. In secondary forest and natural clear-
ings, the proportion of insects captured diminished
with increasing height, which contrasts with results
reported elsewhere (Sutton 1989). This discrepancy
may be because my traps were located below rather
than above the top of the canopy.
The most abundant group of insects captured in the
sticky traps was Diptera, followed by Hymenoptera
and Coleoptera. Diptera constituted a larger propor-
tion in secondary forest, and Hymenoptera in natu-
ral clearings and primary forest; Coleoptera (Staphy-
linidae, Curculionidae, Scolytidae) were similarly
distributed in all three habitats. Although numbers of
Coleoptera generally decreased with increasing height,
in primary forest their numbers increased again at the
highest level (15 m). Psocoptera and Homoptera did
not follow this general pattern; the greatest number
of these were captured in primary forest at level 3
(2.5-2.8 m); the greatest number of Homoptera were
taken at the same level in natural clearings.
Although the sticky traps provided comparative
evaluations of insect populations in the three forest
habitats and at different heights, they may not reflect
the types of prey that are captured by spiders (Chacon
and Eberhard 1980, Eberhard 1990). In other studies
(Uetz and Biere 1980, Uetz and Hartsock 1987), traps
of sticky threads captured prey similar to those cap-
tured by Micrathena gracilis. However, spiders select
and consume only a subset of the insects entrapped
in the web (Castillo and Eberhard 1983). Presumably
both web type and foraging strategy affect prey selec-
tion by orb-weaving spiders (Craig 1989).
The greater abundance of insects in the lowest
strata of the forest coincided with the greater relative
abundance of orb-weaving spiders in these same lev-
els. However, in primary forests, a second peak of
insect abundance occurred in the canopy, which was
not reflected in a similar increase in spider abun-
dance. More research is needed on all aspects of arach-
nid biology in Monteverde.Acknowledgments I thank William Eberhard for his
advisory role during this study, and Prof. Herbert Levi,
Jonathan Coddington, and Brend Opell for their help
with spider identification. This essay is part of my
MSc Thesis at the Universidad de Los Andes (Bogota,
Colombia). This study was made possible by the sup-
port of the Fondo FEN-Colombia, the Wildlife Conser-
vation Society (formerly Wildlife Conservation Inter-
national/New York Zoological Society), and Reserva
Natural La Planada; ecological disturbance study funds
were provided by Conservation International/John D.
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142 Insects and Spiders