The Euglossini are a key group for studying the traits that promote or hinder highly social behavior in bees because it is the only tribe in the Apine clade without large colonies or females with distinct life histories, e.g. queens and workers. There have been few studies on behavior of orchid bee females in nests because these nests are not found easily. Taking advantage of the relatively high abundance of Eg. nigropilosa nests at Reserva Natural La Planada, Colombia, we examined social behavior of Eg. nigropilosa individuals in five nests (3 original and 2 reused) for nine months. We report this species to have the largest colonies known for Euglossa, with nests reaching up to 22 individuals, and all nests containing more than one female bee from the same generation. These nests presented many traits that correspond to communal insect colonies. No generational overlap and no cooperative brood care were detected. We examined natural enemies and resource limitation as important factors for group nesting. We examined parasitoid attacks to cells in a nest with females and one without females. We also searched for nesting locations and examined nest re-use as indicators of nest site limitation. Lastly, we examined behavioral and physiological differences among females in the same nest. Such differences could be the bases for evolution of alternative life histories among group living females. We examined extent of ovary development and oviposition rates in similarly aged females in the same nest. We found large variation in reproductive effort of young females. We also examined differences in resin foraging and cell usurpation behaviors. Behavioral specialization was observed, with some individuals bringing only resin to the nest. Inside the nests, bees had territories in which they constructed and defended cells. This territoriality may be a defense against usurpation of provisioned cells by nest mates.

The variation of the diversity, composition, functional diversity and species richness of lichen communities along an altitudinal gradient in the Chocó biogeographic region of the department of Valle del Cauca, Colombia, is evaluated basing on 2732 samples belonging to 690 species of corticolous lichens. The dominant families were Graphidaceae, Parmeliaceae, Lobariaceae and Pyrenulaceae. Alpha lichen diversity showed a concave pattern with respect to altitude, and the zones at low and high elevations had greater diversity. Beta diversity and total richness estimated by rarefaction for locality presented a bell-shaped pattern, with a peak at 1600 m. Lichen functional traits strongly changed with the increase of altitude. Functional diversity presented the same pattern of total richness estimated by rarefaction. These results suggest that the lichen communities of the altitudinal extremes are structured by a strong environmental filter effect, while in the intermediate zones there is an overlap of functional traits, which is reflected in both a high functional and taxonomic diversity. The results suggest that the functional traits used are good substitutes for species to study altitudinal patterns. The high number of indicator species for the altitudinal extremes implies that in a context of climate change, these zones will be more susceptible to the loss of species.

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Terrestrial flora of Malpelo Island, Colombia, Eastern Tropical Pacific. Malpelo Island is located 380km off the mainland continental coast of Colombia, in the Pacific Ocean. Several geological, ecological, and zoological studies, both marine and terrestrial, have been conducted in this island. Despite some marginal comments on some publications, no single specific survey has been devoted to botany so far. In order to make a floristic inventory of the terrestrial flora of this island, three field trips were made in 2010 to collect vascular plants, mosses, and lichens, as well as data on their distribution within the island. We collected and identified 25 species of lichens, two species of vascular plants and one moss. Lichens were the most diverse group found, including records of four new genera (Endocarpon, Fuscidea, Lecanographa and Verrucaria) and 13 new species for Colombia. The high lichen richness on Malpelo might be explained by their efficient form of asexual reproduction (soredia and isidia), that may have facilitated their transport to the island by migrating birds or wind. Once on the island, it is possible that lichens persist by being chemically protected against herbivores. The great number of new generic and species records for Colombia is explained by the low number of studies in saxicolous lichens conducted so far in the country, particularly on coastal areas and remote islands. Only two species of vascular plants were collected, a grass, Paspalum sp., and a fern, Pityrogramma calomelanos, and both of them correspond to new determinations for Malpelo. A moss species previously reported but with no positive identification was collected and identified as Octoblepharum albidum. Other species previously reported, for example, some species of shrubs, were not observed. The low number of vascular plants is probably due to a combination of soil conditions and herbivory by land crabs. This study is the first complete inventory of the flora of Malpelo and is a starting and reference point for future comparisons among islands in the Eastern Tropical Pacific. Rev. Biol. Trop. 62 (1): 327-336. Epub 2014 March 01.

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