The Neotropical ithomiine butterflies (Lepidóptera: Nymphalidae: Ithomiinae) are the
models in mimicry rings and are relatively well known taxonomically. For these reasons,
they are often chosen as biological indicator species. The present study was undertaken to
characterize the ithomiine community in dense evergreen upland tropical rain forest at the
Ferreira Penna Scientific Station in the Caxiuanã National Forest, municipality of
Melgaço, Pará, Brazil, as well as to test the efficiency of the sampling protocol for this
group of butterflies. In a forested area of 500 by 500 m, collections were made with two
methods. Trapping was done during five consecutive days per month with baits of
Heliotropium indicum leaves and flowers within five 100 by 100 m parcels, each of which
contained five understory and five canopy traps. On the same days, in nearby areas,
manual capture was undertaken with entomological hand nets. Sampling was done in July
and October 2004 and January to November 2005. Collection effort was 2000 trap-hours
per month and 40 net-hours per month. A total of 1844 ithomiine butterflies (14 species)
was collected. Hypothyris ninonia (Hübner, [1806]) and Napeogenes rhezia (Geyer, [1834])
were the most abundant species. Both horizontal and vertical diversity were homogeneous,
in spite of a tendency for most species to exhibit a preference for the understory. Sex ratios
were unbalanced, and males were more common in the research area, but this could be an
artifact of collection methods since only males are attracted to the alkaloid-bearing baits.
Both collection methods showed similar species richness, even though three species were
caught only by hand netting and two only in the baited traps. More specimens of Methona
sp. were caught by hand netting than by trapping, indicating that this species is less
attracted to the bait. Total ithomiine catch was inversely correlated with rainfall. The
research area has few ithomiine species, including both common and rare species, whose
abundance varies with the yearly rainfall pattern. Traps in the forest understory baited with
the alkaloid source were most efficient, and their use is recommended for ithomiine
community sampling.
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