RESUMO. Primeiro registro de um ninho de Ceratina (Ceratinula) fioreseana Oliveira (Hymenoptera: Apidae). É fornecido o primeiro registro de um ninho de Ceratina (Ceratinula) fioreseana Oliveira, 2020, uma espécie que foi recentemente descrita para o domínio do Cerrado. O ninho foi coletado em um cultivo de Passiflora edulis Sims (Passifloraceae) no estado de Minas Gerais, Brasil e foi construído em um ninho-armadilha, um pecíolo seco de Cecropia pachystachya Trécul (Urticaceae). Dentro do ninho havia uma fêmea e uma célula de cria sem partição contendo uma pupa, a qual a fêmea adulta emergiu 28 dias após pupação. A análise polínica revelou a dominância de grãos de pólen de Emilia fosbergii Nicolson (Asteraceae), uma espécie ruderal observada a poucos metros do ninho. O registro de uma fêmea adulta dentro do ninho juntamente com uma pupa e a ausência de partição na célula de cria podem sugerir comportamento social nesta espécie de abelha.

ABSTRACT. We provide herein the first report of a nest of Ceratina (Ceratinula) fioreseana Oliveira, 2020, a species that was recently described for the Cerrado domain. The nest was collected in a Passiflora edulis Sims (Passifloraceae) plantation in Minas Gerais State, Brazil and was built in a trap nest, a dry petiole of Cecropia pachystachya Trécul (Urticaceae). Within the nest there was a living female and a brood cell without partition containing a pupa, whose adult female emerged 28 days after pupation. Pollen analysis revealed the dominance of Emilia fosbergii Nicolson (Asteraceae) pollen grains, a weed recorded a few meters from the nest. The record of an adult female within the nest with a pupa and the absence of nest partition might suggest social behavior in this bee species.

For the first time, confirmed host records are reported for the monotypic Ericrocidini genus Aglaomelissa Snelling & Brooks, 1985. Aglaomelissa duckei (Friese, 1906) emerged from trap-nests of Centris (Heterocentris) analis (Fabricius, 1804) and C. (Heterocentris) terminata Smith, 1874 from two sites in the Brazilian Amazonian region. The parasitism ratio caused by A. duckei was high, varying from 80 to 100% of the brood cells in a single trap-nest. Also, a compilation of the known host records for the species of Ericrocidini is presented and host-parasite associations are discussed. Host associations are known for seven of the 11 genera and about 17 of the 42 species of the tribe, involving a total of 34 confirmed or putative host species of Centridini bees. All species of the tribe are known to attack only nests of Centris Fabricius, 1804, except Mesoplia rufipes (Perty, 1833) that also parasitizes nests of Epicharis Klug, 1807. Although the phylogenetic relationships within Ericrocidini and among the subgenera of Centris are not well resolved, the current knowledge of the host-parasite associations points to a relatively high degree of specificity and possible coevolution between them.