Rapid assessment of the orchid bee fauna (Hymenoptera: Apidae: Euglossini) in the vicinity of an urban Atlantic Forest remnant in São Paulo, Brazil

Euglossini (Hymenoptera: Apidae, Apini), also known as orchid bees, are endemic to the Neotropical region (Nemésio and Rasmussem, 2011). They are well-known and widely distributed taxon in the Atlantic Forest with more than 60 species (included in four distinct genera) registered in this biome (Nemésio, 2009; Garraffoni et al., 2017). The Atlantic Rain Forest originally occupied about 15% of the Brazilian territory, but it was completely fragmented in forest remnants, and now covers 11-16% of its original area (Ribeiro et al., 2009; Joly et al., 2014). Our knowledge about orchid bee diversity in urban forest fragments is very scarce (Nemésio and Silveira, 2007; Cordeiro et al., 2013), although diverse communities of wild bees have been surprisingly found in cities around the world (Nemésio and Silveira, 2007; Burr et al., 2016). Thus, our aim in this study was a rapid assessment of the orchid bee fauna in the vicinity of an Atlantic Forest remain. The strategy of intensive sampling over a few days in the rainy season are common and has been demonstrated to be very useful to know the orchid bee fauna of an area (Nemésio, 2013a, b). Data were collected in an urban area (22º4940”S-47º0610”W; altitude 630 m), among fruit and ornamental trees, distant 200 m of the east edge of an Atlantic Forest remnant called Santa Genebra Forest (Campinas, SP), the second larger urban forest in Brazil (252 ha). It is a semideciduous forest and the regional climate is the Cfa of Köppen (humid subtropical with a hot summer). Orchid bee males were collected at a fixed site using seven bait traps as described in Viotti et al. (2013), and bottles of 0.5 L. Each trap received one of the seven baits: 1,8-cineole, eugenol, vanillin, β-ionone, benzyl acetate, methyl trans-cinnamate, and methyl salicylate; and were randomly hanged in shaded branches at about 1.5 m above the ground and distant at least 2 m from each other. The collections were done during five consecutive days (from day 6th to 10th) in February of both 2015 and 2016, from 9:00 to 17:00 h (when the bees are most active). The scents were replaced every day, and cineole three times a day. Captured bees were pinned, identified and deposited at Coleção de Abelhas da Universidade Federal dos Vales do Jequitinhonha e Mucuri. Taxonomic decisions were based on Moure's Bee Catalogue (Moure et al., 2012). Species accumulation curves were constructed for the data set from each sampling year separately or for both years jointly. Sampling efficiency was also evaluated by nonparametric richness estimators (Chao 1, Chao 2, Jackknife 1, Jackknife 2, and Bootstrap) available in the EstimateS 9.1.0 software (Colwell, 2006).(AU)

Silencing of Apis mellifera dorsal genes reveals their role in expression of the antimicrobial peptide defensin-1.

Like all other insects, two key signalling pathways [Toll and immune deficiency (Imd)] regulate the induction of honey bee immune effectors that target microbial pathogens. Amongst these effectors are antimicrobial peptides (AMPs) that are presumed to be produced by the nuclear factors kappa B (NF-κB) Dorsal and Relish from the Toll and Imd pathways, respectively. Using in silico analysis, we previously proposed that the honey bee AMP defensin-1 was regulated by the Toll pathway, whereas hymenoptaecin was regulated by Imd and abaecin by both the Toll and Imd pathways. Here we use an RNA interference (RNAi) assay to determine the role of Dorsal in regulating abaecin and defensin-1. Honey bees have two dorsal genes (dorsal-1 and dorsal-2) and two splicing isoforms of dorsal-1 (dorsal-1A and dorsal-1B). Accordingly, we used both single and multiple (double or triple) isoform knockdown strategies to clarify the roles of dorsal proteins and their isoforms. Down-regulation of defensin-1 was observed for dorsal-1A and dorsal-2 knockdowns, but abaecin expression was not affected by dorsal RNAi. We conclude that defensin-1 is regulated by Dorsal (Toll pathway).

Trap-Nesting Bees in Montane Grassland (Campo Rupestre) and Cerrado in Brazil: Collecting Generalist or Specialist Nesters.

Species richness and seasonal abundance of solitary bees were investigated in rocky, montane grassland (campo rupestre) (1180 m asl) and cerrado sensu stricto (680 m asl) in the Biribiri State Park, Diamantina, state of Minas Gerais, Brazil. Three hundred nineteen nest traps of bamboo canes and black cardboard tubes were monthly inspected at each site during 15 months. A total of eight species of bees built 97 nests. Four species were common to both sites. Tetrapedia aff. curvitarsis Friese and Tetrapedia aff. peckoltii Friese were the most abundant at campo rupestre and cerrado s.s., respectively, followed by Centris analis (Fabricius) in campo rupestre and Centris tarsata Smith in cerrado s.s. The nesting peaks occurred in May in campo rupestre and in February in cerrado s.s. Three cuckoo bees and one bee-fly were collected as natural enemies. The findings suggest that differences between the sites were related more to ecological factors (floral resources, natural nest sites) than to the altitudinal difference. The species richness was similar to that in other habitats with open vegetation. We demonstrate the need to use several types of trap-nest to increase the range of species sampled; some species used only one of the two types traps provided. We also comment on the limitations of trap-nests in cerrado vegetation. Most cerrado species of bees are very selective in their choice for a nesting site, but bees that use trap-nests are more generalists.

Species Diversity and Temporal Variation of the Orchid-Bee Fauna (Hymenoptera, Apidae) in a Conservation Gradient of a Rocky Field Area in the Espinhaço Range, State of Minas Gerais, Southeastern Brazil.

This study investigated the orchid-bee community in a conservation gradient of the high-altitude rocky fields in the state of Minas Gerais, Brazil. Sampling was performed at two sites with different anthropic influences: a disturbed area (DA), with exotic plant species, and a preserved area (PA). From September 2009 through February 2011, males of euglossine bees were sampled using aromatic bait-traps. We collected a total of 819 specimens belonging to 11 species and three genera: Euglossa Latreille, Eulaema Lepeletier, and Eufriesea Cockerell. Despite the proximity of DA and PA (about 1.2 km), differences in orchid-bee abundance and richness were observed. Higher abundance was observed in the PA (n = 485) compared with the DA (n = 334). Eight species were common to both sites, and only the DA showed exclusive species. The DA showed higher diversity and higher estimated species richness. Euglossa leucotricha Rebêlo & Moure was the most abundant species at both sites followed by Euglossa melanotricha Moure. Higher abundance and richness were found in the warm rainy season. This study contributes to the knowledge of the orchid-bee fauna in the rocky fields and suggests that the greater resource availability in the DA was responsible for the higher orchid-bee diversity.