wasp coloration have been studied surprisingly little.
Prey choice by visually hunting insect predators such
as dragonflies may also play a role in the evolution
of wasp body colors (O'Donnell 1996a). Many Monte-
verde wasp colonies fall prey to humans, particularly
nests on buildings and in road banks. Eusocial wasps
are important predators of herbivorous insects in the
Monteverde area, and they may also play a role as
pollinators (O'Donnell 1996b). Most species that nest
near humans are not aggressive and pose little threat
if not disturbed. Given their potentially significant
role in local ecology, destruction of vespid colonies
should be avoided.
Acknowledgments Thanks to Susan Bulova for help-
ful comments on the manuscript. Jim Hunt and Frank
Joyce generously shared their extensive knowledge
and enthusiasm for tropical social wasps and helped
with fieldwork in Monteverde. Financial support was
provided by the National Science Foundation, and
permission for research and collecting, by the Costa
Rican Ministry of Natural Resources.
4.7.4. A Dual Mimicry Complex Involving
Eusocial Wasps (Hymenoptera: Vespidae)
Sean O'Donnell & Frank Joyce
Batesian mimicry results when nondefended species
evolve to resemble noxious models, and Miillerian
mimicry results when chemically defended species
evolve to resemble each other (Wickler 1968). Several
cases of mimicry in the eusocial Vespidae have been
described (Richards 1978, West-Eberhard et al. 1995).
More aggressive species of neotropical Vespidae,
often swarm-founding wasps with large colony sizes
(tribe Epiponini), are mimicked by other eusocial
wasps. Wasps in the genus Mischocyttarus often
mimic epiponines. Although capable of stinging,
Mischocyttarus will not sting humans even in nest
defense; some species flee their nests when disturbed.
Mischocyttarus mastigophorus exhibits two color
morphs that co-occur in Monteverde. Although other
species of Mischocyttarus are known to vary in body
color over their geographic ranges (J. Carpenter, pers.
comm.), this is the first report of a eusocial wasp with
two discrete color morphs co-existing within a popu-
lation. Our research suggests that M. mastigophorus
exhibits dual mimicry, with two species from the epi-
ponine genus Agelaia serving as models for the M.
mastigophorus color morphs. Furthermore, the rela-
tive frequencies of the M. mastigophorus color morphs
corresponded with the relative abundances of their
putative model species at different elevations, as
would be expected if the presence of the models af-
fected the fitness of the morphs.
Colonies of M. mastigophorus were collected in
1994 and 1996 from the eaves and walls of buildings
in Monteverde. Colonies were collected at night to
ensure that all adults were present. Adult wasps were
frozen for colony population counts. Additional colo-
nies were examined in the field and surveyed for
adults during daylight hours. Locations of colonies
of putative model species (Agelaia yepocapa and A.
xanthopus) were recorded from July 1988 to January- Presence of foragers of the model species were
recorded at meat baits placed at different elevations
(O'Donnell 1995).
The color shades and pattern of the M. mastigo-
phorus pale morph closely matched those of Agelaia
yepocapa, and the dark morph closely resembled
A. xanthopus. Agelaia yepocapa and A. xanthopus
are among the most commonly encountered foraging
wasps at Monteverde. Both Agelaia species typically
have colonies of several thousand adults, which they
vigorously defend against intruders (O'Donnell and
Jeanne 1990).
Males and females within M. mastigophorus morphs
are similar in color and in pattern. Males are easily
recognized by the possession of elongate, filamentous
antennae; no intergradation between the morphs is
evident. The pale morph and A. yepocapa are exten-
sively yellow laterally, and black with yellow mark-
ings on the dorsum. The model and mimic share simi-
lar patterns of black markings, particularly on the
dorsum of the gaster (distal segments of the abdomen).
The greater amount of black on the gaster and the
deeper shade of yellow coloration distinguish both
model and mimic from sympatric yellow and black
congeners (e.g., M. mexicanus and A. areata). The
coloration of the dark morph is almost identical to that
of its putative model, A. xanthopus. The darkmorph's
body is deep chocolate brown, with yellow on the legs
and yellow mandibles. No other vespids share this
color pattern.
Mischocyttarus mastigophorus ranges from 1475
m to at least 1600 m (Table 4.2). The range of A. yepo-
capa appears to include lower elevations than M.
mastigophorus and may not include the upper eleva-
tions of the mimic's range. The range of A. xanthopus
appears to overlap the elevational range of M. mas-
tigophorus completely. The relative frequencies of
M. mastigophorus morphs change with elevation
(Table 4.2), presumably in response to differences in
the elevational ranges of the model species. Preferen-
tial feeding by predators on one morph, depending on
experience with different model species at different
elevations, could generate the observed correspon-
dence of mimic and model abundances. Choice tests
with visually hunting predators could be used to test
this hypothesis.
131 Insects and Spiders