In this study, we compare orchid bee communities surveyed in four forest remnants of the Atlantic Forest and four reforested areas characterized by seasonal semi-deciduous forest vegetation in different successional stages (mature and secondary vegetation), located in southern Brazil. The sizes of forest remnants and reforested areas varied from 32.1 to 583.9 ha and from 11.3 to 33.3 ha, respectively. All reforested areas were located near one forest remnant. During samplings, totaling nine per study area, euglossine males were attracted to eight scent baits and captured with bait trap and entomological nets. Each forest remnant and its respective reforested area were sampled simultaneously by two collectors. We collected 435 males belonging to nine species of orchid bees distributed in four genera. The number of individuals and species did not differ significantly between different areas, except for a reforested area (size 33.3 ha), which was located far from its respective forest remnant. Our findings also revealed an apparent association between an orchid bee species (Euglossa annectans Dressler 1982) and the most preserved area surveyed in our study, suggesting that this bee is a potential indicator of good habitat quality in recuperating or preserved areas. Our results suggest that reforested habitats located near forest remnants have a higher probability of having reinstated their euglossine communities.

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We investigated the nesting behavior of females of Epicharis dejeanii and the architecture of their nests, in a large aggregation in a Restinga area, on Ilha do Superagui, southern Brazil. Surveys were carried out intermittently through the warm-wet seasons from different years between 2013 and 2017. The nest aggregation occupied an area of approximately 2,000 m2 and was situated on a sand bank and on flat sandy soil. Each nest consisted of a long unbranched tunnel, averaging 1.45 ± 0.35 m (N = 8), connected to a single brood cell with a mean length of 3.13 ± 0.2 cm (N = 13) and mean diameter of 1.2 ± 0.1 cm (N = 11). On average, females carried out 4.0 ± 2.4 foraging trips per day (N = 109) to collect floral resources for provisioning brood cells. Similar times were spent by females in their foraging trips for: only pollen (15.8 ± 14.3 min, N = 72), oil (22.5 ± 15.7 min, N = 45), or both resources (17.0 ± 15.1, N = 63).  Our findings reveal that some variation in both nesting architecture and female behavior of E. dejeanii during nesting activities can occur in different locations from the same region.

In recent decades, the use of the trap-nest technique has helped to increase knowledge on the nest architecture of many orchid bee species. This study describes the nest architecture of Eufriesea aff. auriceps constructed in trap-nests made of dried bamboo internodes (canes). The nests were placed in remnants of Atlantic forest and in reforested areas next to forest remnants and monitored monthly from August 2015 to August 2016 and from August 2018 to August 2019 in southern Brazil. The bamboo internodes occupied by bees varied in internal diameter from 1.0cm to 2.0 cm (`X = 1.7; SD = 0.3; N = 12) and in length from 11.0 cm to 28.0 cm (`X = 19.5; SD = 4.8; N = 12). The total size of the nests inside the bamboo internodes ranged from 9.0 cm to 19.9 cm (`X = 14.3; SD= 3.9; N = 12). The number of brood cells constructed per nest varied from 1 to 10 (`X = 4.0; SD = 2.3; N = 15). The cells were built with small pieces of bark cemented with resin, linearly arranged along the bamboo tube. Internally, the cell wall was lined with resin. The cells measured 1.5-3.0 cm (`X = 2.3 ± 0.5; N = 48) in length and 1.4-1.7 (`X = 1.5 ± 0.1; N = 17) cm in width. The internal contour of the cells was elliptical. Females of Eufriesea aff. auriceps occupied trap-nests in both the forest remnants and in areas undergoing restoration.