pyrrolizidine alkaloids to females in the spermato-
phore, a packet of sperm and nutrients. Females gain
protection and access to pyrrolizidine alkaloids that
they place in the shell of their eggs (Brown 1984).
The evolution of transparent wings in Pieridae,
Satyrinae, Ithomiinae, and some moths appears to be
a classic case of convergence. The groups are not
closely allied and almost certainly had opaque com-
mon ancestors. The presence of many genera with
both transparent and opaque wings also suggests con-
vergence. Among ithomiines, the convergence might
be explained by Miillerian mimicry; that is, individu-
als of all species benefit by mutual resemblance be-
cause their unpalatability is more easily recognized
and remembered by predators. Convergence between
ithomiines and satyrines, and between ithomiines
and Dismorphia, may be a case of Batesian mimicry,
where the palatable satyrine and pierid are mistaken
for unpalatable ithomiines and thus avoided by preda-
tors. Transparent wings may also be the ultimate cryp-
tic, or camouflage, coloration. Unlike opaque patterns
that constrain the organism to match only some of
many potential backgrounds, transparency allows
perfect crypsis in all situations. In this case, the "link-
ing aspect" favoring convergence in clearwings may
be that transparent coloration is the best type of cryp-
tic coloration for organisms that must move freely
against a complex background of colors and shapes.
Little is known about the ecology and behavior of
these butterflies. The palatability of D. theucharila is
questionable. Much of the basic natural history of
Satyrinae is not known. Feeding experiments with
visual predators using the brown satyrine P. helvetica
and the transparent and pink C. menander against
many natural backgrounds would provide support for
the hypothesis that transparency adds cryptic value
over the more normal brown coloration of cryptic
butterflies. Comparing palatability of both D. theu-
charila and C. menander and ithomiine clearwings
will determine their status as Batesian or Miillerian
mimicry.
4.5.5. Variable Chemical Defense
and Mimicry
Alan /?. Masters
Although best known for its clearwing species (see
Sec. 4.5.4), the nymphalid subfamily Ithomiinae more
commonly displays striking color patterns. Four color
patterns are recognized: clear wing, tiger stripe, yel-
low and black, and tawny (Papageorgis 1975, Drum-
mond 1976, Haber 1978, Masters 1992). Each color
pattern is represented in an area by several species
in a handful of genera. The color patterns are usually
represented in the same geographical area, a puzzlingsympatry. According to classical Miillerian mimicry
theory, all unpalatable butterflies in an area should
converge on a common color pattern to best educate
potential predators and thereby gain greater indi-
vidual protection.
My research in Monteverde addressed the para-
dox of sympatric Miillerian mimicry complexes. I
chose ithomiines because they (and pierids) were the
organisms on which both Bates (1862) and Miiller
(1879) formulated their concepts of mimicry. Bates
examined the mimicry of a Dismorphia sp. (Pieridae)
and proposed that its resemblance to a sympatric
ithomiine was to fool predators into thinking it was
also unpalatable. Miiller proposed that two unpalat-
able ithomiines who share a common color pattern
both benefit from the resemblance because their
predator would make fewer mistakes with just one
pattern to associate with unpalatability. Although
both naturalists assumed the unpalatability of itho-
miines from indirect evidence (tough wings, long life
span, beakmarks on their wings, slow flight), no evi-
dence existed for the unpalatability of ithomiines to
visual predators, that is, those capable of forming
learned aversions to unpalatability that they could
associate with the ithomiines' color pattern (though
preliminary feeding experiments suggested this;
Haber 1978).
I studied butterflies in the tawny complex, which
have a brown to orange translucent appearance with
white or yellow spots and stripes. Pteronymia ful-
vescens fed to captive Green Fence Lizards (Scelo-
perus malachiticus) and Blue Crowned Motmots
(Momotus momota) were rejected over palatable
Anartia fatima (Nymphalinae) (Masters 1992). Fur-
ther, P. fulvescens raised from eggs on Solanum bre-
nesii (Solanaceae) were palatable as adults until fed
a solution with pyrrolizidine alkaloids, the same chem-
icals protecting ithomiines from the spider Nephila cla-
vipes (Araneae) (Brown 1984, Masters 1990).
Collecting in Monteverde along the Rio Guacimal
near the dairy plant (ca. 1400 m) for one year (1987-
88), I found about 20 tawny ithomiine species. The only
similar-looking non-ithomiine, captured twice, was
Lycorea ilione (Danainae), which flies higher and is
almost certainly a Miillerian mimic. Each month, I
captured the first 100 ithomiine individuals encoun-
tered. In all, 15 species were captured fewer than ten
times. Of the remaining five (Ithomia heraldic a, I.
xenos, Pteronymia fulvescens, P. notilla, and Hypo-
thyris euclea), all had capture totals of greater than 100
over the year. Of these, I collected at least 20 of each
sex for chemical analysis. Mark-release-recapture stud-
ies provided population estimates each month. Trans-
ects throughout the Monteverde community gave a
tally of pyrrolizidine alkaloid-containing flowers.121 Insects and Spiders