Oligolectic bees collect pollen from one or a few closely related species of plants, whereas polylectic bees visit a variety of flowers for pollen. Because of their more restricted range of host plants, it maybe expected that specialists exist in smaller, more isolated populations, with lower effective population sizes than generalists. Consequently, we hypothesized that oligolectic bees have reduced levels of genetic variation relative to related polylectic species. To test this hypothesis, we used five phylogenetically independent pairs of species in which one member was oligolectic and the other was polylectic. We assayed genetic variation in our species pairs at an average of 32 allozyme loci. Within each species pair, the oligolectic member had fewer polymorphic loci, lower average allelic richness, and lower average expected heterozygosity than its polylectic relative. Averaged over all species pairs, this corresponds to a 21% reduction in allelic richness, a 72% reduction in the proportion of polymorphic loci, and an 83% reduction in expected heterozygosity in specialists compared with generalists. Our data support the hypothesis of reduced effective population size in oligolectic bees and suggest that they may be more prone to extinction as a result. We suggest that in instances in which bee specialists are involved in mutually codependent relationships with their floral hosts, these mutualisms may be endangered for genetic and ecological reasons. Genética de la Conservación de Mutualismos Potencialmente en Peligro: Bajos Niveles de Variación Genética en Abejas Especialistas Versus GeneralistasResumen: Abejas oligolécticas colectan polen de una o varias especies de plantas cercanamente relacionadas, mientras que abejas polilécticas visitan una variedad de flores para polen. Debido a que su rango de plantas huésped es más restringido, puede esperarse que las especialistas existan en poblaciones más pequeñas y más aisladas, con menor tamaño poblacional efectivo, que las generalistas. Consecuentemente, planteamos la hipótesis de que abejas oligolécticas tienen niveles reducidos de variación genética en relación con especies polilécticas. Para probar esta hipótesis utilizamos cinco pares de especies filogenéticamente independientes en los que un miembro era oligoléctico y otro poliléctico. Analizamos la variación genética en nuestros pares de especies en un promedio de 32 loci de alozimas. En cada par de especies, el miembro oligoléctico tenía menos loci polimórficos, menor promedio de riqueza alélica y menor promedio de heterocigosidad esperada que su pariente poliléctico. Promediado en todos los pares de especies, esto corresponde a una reducción de #These two authors contributed equally to this paper.§Deceased. 196Conservation Genetics of Oligolectic Bees Packer et al.21% de la riqueza alélica, reducción de 72% en la proporción de loci polimórficos y una reducción de 83% en la heterocigosidad esperada en especialistas comparados con generalistas. Nuestros datos soportan la hipótesis de reducción en el tama...

An aggregation of the oil-collecting bee Epicharis dejeanii Lepeletier was studied at Ilha das Flores, southern Brazil. Data on seasonality, types of floral resources collected, and nesting biology were registered. The nesting area occupied 120 m 2 with density of up to 8 nests/m 2. The tunnel entrances remained always open and surrounded by a tumulus. Adult activity lasted approximately 70 days. The females built the nest, provisioned food, and layed the egg in 4 days. The nest's architecture was very diverse, and they were between 40 and 140 cm in depth with one or two brood cells at the end of the tunnel. Diapause occurred in the postdefecating larval stage, and there was no cocoon. Immature stages and nest architecture are described and illustrated.

In this paper, a complete taxonomic revision of the species of Centris (Wagenknechtia) Moure is presented for the first time. The following species are recognized: Centris cineraria Smith, C. escomeli Cockerell, C. moldenkei Toro & Chiap-pa, C. muralis Burmeister, C. orellanai Ruiz, C. rhodophthalma Pérez and C. vardyorum Roig-Alsina. Floral associations, distribution records, and diagnoses of both sexes based on type specimens, are given. An identification key, illustrations, along with an updated catalogue of all species of the subgenus, are also provided. In addition, a neotype for Centris orel-lanai is designated.

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The species of Centris of the hyptidis group are revised. The group, composed by C. hyptidis Ducke, C. hyptidoides Roig-Alsina, and C. thelyopsis n. sp., exhibits unique morphological characters within the genus, like foreand midtrochanters with a laminar expansion at the base, and elaiospathes strongly modified. An updated catalog, and floral and distributional records are provided for each species, as well as an identification key and a distribution map. The male of C. hyptidoides is described for the first time and a modern diagnosis for C. hyptidis is presented. A new species, C. thelyopsis n. sp., is described from Goiás State, in central Brazil. It can be easily distinguished from the two previously known species by its predominant orange pilosity, including that of the hind legs and metasoma.