''Bombus pullatus'' is a tropical,
eusocial species of
bumblebee native to
Mexico and
Central America. Unlike many bumblebee species, they live in colonies with multiple queens.
Distribution & Taxonomy
The majority of this species occurs in the lowlands of Central America, with approximately 90% of colonies being found in
Costa Rica
Costa Rica (, ; ; literally "Rich Coast"), officially the Republic of Costa Rica ( es, República de Costa Rica), is a country in the Central American region of North America, bordered by Nicaragua to the north, the Caribbean Sea to the no ...
.
However they have been found at elevations higher than 3 km above
sea level.
Colonies have been confirmed in
Guatemala
Guatemala ( ; ), officially the Republic of Guatemala ( es, República de Guatemala, links=no), is a country in Central America. It is bordered to the north and west by Mexico; to the northeast by Belize and the Caribbean; to the east by H ...
,
Honduras
Honduras, officially the Republic of Honduras, is a country in Central America. The republic of Honduras is bordered to the west by Guatemala, to the southwest by El Salvador, to the southeast by Nicaragua, to the south by the Pacific Oce ...
,
Nicaragua,
Panama and the south of
Mexico.
''Bombus pullatus'' is considered a more basal member of the genus ''
Bombus'' compared to ''
Bombus pauloensis
''Bombus pauloensis'' is a neotropical bumblebee, formerly known as ''Bombus atratus'', that is found throughout regions of South America, including Colombia, Ecuador, Brazil, and Argentina. It lives in social colonies that include a founder que ...
'' and ''
Bombus transversalis''.
Historically, ''Bombus pullatus'' has commonly been misidentified as ''Bombus pauloensis'' and vice versa in many collections. Molecular analyses (such as
DNA profiling
DNA profiling (also called DNA fingerprinting) is the process of determining an individual's DNA characteristics. DNA analysis intended to identify a species, rather than an individual, is called DNA barcoding.
DNA profiling is a forensic tec ...
) of these specimens are required to accurately identify both species. This issue is why the IUCN has agreed to reject data on this species that is more southern than
Panama.
Behaviour
This species is known to be quite aggressive, stinging humans within approximately 6 m of the nest if it is disturbed.
Unlike most
bumblebees
A bumblebee (or bumble bee, bumble-bee, or humble-bee) is any of over 250 species in the genus ''Bombus'', part of Apidae, one of the bee families. This genus is the only extant group in the tribe Bombini, though a few extinct related gener ...
, ''Bombus pullatus'' colonies contain multiple
queens (a form of
polygyny) like their close relative ''
Bombus pauloensis
''Bombus pauloensis'' is a neotropical bumblebee, formerly known as ''Bombus atratus'', that is found throughout regions of South America, including Colombia, Ecuador, Brazil, and Argentina. It lives in social colonies that include a founder que ...
'' (who rotate between polygyny and
monogyny). However ''Bombus pullatus'' colonies have a comparatively higher number of queens. In one nest a total of 36 queens were sampled in a colony with a total of 343 individuals.
Workers of this species are significantly smaller than males.
This bee forages on many kinds of plants, including ''
Miconia
''Miconia'' is a genus of flowering plants in the glory bush family, Melastomataceae, native to warm temperate to tropical regions of the Americas. The species are mostly shrubs and small to medium-sized trees up to 15 m tall. The generic name ...
'' sp., ''
Monochaetum
''Monochaetum'' is a neotropical genus of shrubs and subshrubs with about 54 species. It occurs in warm temperate to tropical montane habitats from Mexico and Central America to the South American Andes of Colombia, Venezuela, Ecuador and Peru ...
'' sp., ''
Solanum'' sp. ''
Mimosa'' sp., and ''
Spermacoce'' sp. Individual
worker bees have displayed preferences for particular plant species.
Foraging rate was calculated in one study to be 2.6-9.5 bees per minute. Pollen collectors had the highest activity in the early morning, however nectar collectors had a relatively constant rate during the day. Foraging trips lasted approximately 50 minutes.
Nesting
Their nests are mostly found on the ground, anchored to sturdy plants. This is thought to protect them from tropical storms. Much like their close relative ''
Bombus pauloensis
''Bombus pauloensis'' is a neotropical bumblebee, formerly known as ''Bombus atratus'', that is found throughout regions of South America, including Colombia, Ecuador, Brazil, and Argentina. It lives in social colonies that include a founder que ...
'', their colonies display a degree of perenniality.
One old nest was observed to contain both the bee colony and a colony of the leafcutter ant ''
Acromyrmex octospinosus'', which was occupying cells along the edge that had been abandoned by the bee. This bee can be rare in parts of its range with wet tropical climates because it is difficult to find a suitable dry nesting site and maintain it in such moist conditions.
Their colonies are thought to consist of approximately 300
workers, however this is based on only counts from two individual nests.
One nest was discovered 5.5 m above the ground, indicating that this species is not purely ground-nesting. This nest also appeared to be the second nest site of this colony as old worker cells were absent in it. This indicated that the colony was not sedentary unlike bumblebees in temperate regions.
"groom" the nest by moving leaves that they have shredded into the nest, then pulling or kicking it onto the sides to fortify it.
References
{{Taxonbar, from=Q5806936
Bumblebees
Insects of Mexico
Insects of Central America
Insects described in 1913