below 1500 m, especially in the lowland rain forests
of the Caribbean and on the Osa Peninsula. I have
found only seven species at altitudes above 1500 m:
Trigona fulviventris, T. corvina, Scaptotrigona mexi-
cana, Melipona melanopleura, Partamona sp. (near
cupira), P. grandipennis, and Meliwillea bivea. Most
of these are black to brownish in color, the yellow-
colored species being restricted to the lowlands. Para-
trigona ornaticeps and Tetragonisca angustula also
occur above 1500 m, although they are rare at this
altitude. Some possible factors limiting the diversity
of stingless bees in cloud forests include limited abil-
ity of individual bees and/or the colony to thermo-
regulate within the nest in cooler environments, re-
duced availability of natural cavities suitable for
nesting, and the presence of parasite species specific
to these altitudes.
Partamona sp., P. grandipennis, and Meliwillea
bivea are common in forests between 1500 and 2000
m and are encountered from the volcanoes in the north-
western part of the country to the Talamanca Moun-
tains in southern Costa Rica and Panama. These are
medium-sized stingless bees, nearly uniformly black
in color, with a shiny cuticular surface. Partamona
grandipennis and M. bivea are found only above 1500
m. These two species nest in tree trunks, whereas
Partamona sp. also nests in earthen banks, artificial
cavities, and semiexposed mud constructions. Par-
tamona sp. has a wide altitudinal distribution (0-2200
m) and is most easily adaptable to mountainous habi-
tats altered by human activity.
Partamona grandipennis is distinguished from
Partamona sp. by its larger size, darker wings, and
wider malar space (area between the eye and man-
dible). The architecture of its nest is unknown. The
nest entrance of the latter species is funnel shaped.
In high elevation cloud forests in Costa Rica, these two
species are abundant and strongly attracted to sugary
substances and campfire ashes. Partamona sp. is an
especially aggressive species near its nest. Upon dis-
turbance, numerous workers come out of the nest to
bite the skin and crawl into the hair of the observer,
sometimes even smearing resins carried from the in-
terior of the nest. Partamona grandipennis demon-
strates the same aggressive habits, which is typical of
some stingless bee species.
Among bees of the Costa Rican highlands, M. bivea
is a genus endemic to Costa Rica and Panama, the only
case of endemism at the generic level in the Meli-
poninae of Central America and Mexico (Roubik et al.
1997). Two nests of this species have been observed
in tree cavities, one in Roupala glaberrima (Pro-
teaceae) in Cerro Echandi and one in a fig tree in
Zurqui de Moravia. The nest entrance is very simple,
lacking a tube or other protruding structure con-
structed by the bees, which differs from that of
Partamona or Scaptotrigona. The brood chamber is
composed of horizontal combs without connections
or pillars extending across the entire brood chamber
(unlike Partamona). The combs are enveloped by sev-
eral interconnected sheets of cerumen ("invorucrum")
having a complex form and a width of 5-6 cm. A dif-
ference of up to 10°C between the inside and outside
of this covering has been measured. Outside the in-
volucrum are the honey and pollen containers, potlike
structures made of fused wax and resin. The pollen
is of different colors and forms and is derived from
different families of plants, with a single container
containing a mixture. This species, together with
Partamona, Scaptotrigona mexicana, and other sub-
families of bees, abound at flowers of secondary growth
plants, for example, Miconia sp. (Melastomataceae)
and Neomirandea angularis (Asteraceae).
The existence of a stingless bee genus endemic to
the cloud forests of Costa Rica and Panama is of bio-
geographic interest. Meliwillea lacks the derived and
distinctive morphological characteristics of other gen-
era and thus appears to be a direct descendent of a
primitive branch of stingless bees. Because the subfam-
ily Meliponinae possibly originated from Gondwana
(the ancient supercontinent of the southern hemi-
sphere), the origin of an endemic primitive genus in
the southern part of Central America suggests pre-
Pleistocene migrations. The presence of this bee
exclusively in the highlands is puzzling, given that
the subfamily is much more diverse in the lowlands.
Our ignorance of many aspects of the biology of
cloud forest bees, and the discovery of an endemic
element in this habitat demonstrate the need to con-
serve forests.4.7.8. Africanized Honey Bees,
Recent Immigrants to Monteverde
Gard Otis
In 1957, 26 colonies of imported African honey bees
escaped from an apiary near Rio Claro, Sao Paulo,
Brazil. An uninformed visitor removed the entrance
grids from the hives, and some of the experimental
colonies escaped. Less publicized was that hundreds
of young unmated African queens were distributed to
beekeepers in the late 1950s to create more produc-
tive hybrid colonies (Spivak et al. 1991). Within a few
years, a feral population of "Africanized" honey bees
that was very similar in behavior, morphology, and
genetics to the bees of the savannah region of east
Africa became established.
The Honey Bee (Apis mellifera) is native to Europe
and Africa. Many different races, or subspecies, have
evolved under the widely different environmental138 Insects and Spiders