More Like this

1. Gut microbiota variation of a tropical oil-collecting bee species far exceeds that of the honeybee

   https://doi.org/10.3389/fmicb.2023.1122489  

   Kardas, Elif; González-Rosario, Angie M.; Giray, Tugrul; Ackerman, James D.; Godoy-Vitorino, Filipa (May 2023, Frontiers in Microbiology)

   Introduction Interest for bee microbiota has recently been rising, alleviating the gap in knowledge in regard to drivers of solitary bee gut microbiota. However, no study has addressed the microbial acquisition routes of tropical solitary bees. For both social and solitary bees, the gut microbiota has several essential roles such as food processing and immune responses. While social bees such as honeybees maintain a constant gut microbiota by direct transmission from individuals of the same hive, solitary bees do not have direct contact between generations. They thus acquire their gut microbiota from the environment and/or the provision of their brood cell. To establish the role of life history in structuring the gut microbiota of solitary bees, we characterized the gut microbiota of Centris decolorata from a beach population in Mayagüez, Puerto Rico. Females provide the initial brood cell provision for the larvae, while males patrol the nest without any contact with it. We hypothesized that this behavior influences their gut microbiota, and that the origin of larval microbiota is from brood cell provisions. Methods We collected samples from adult females and males of C. decolorata ( n  = 10 each, n  = 20), larvae ( n  = 4), and brood cell provisions ( n  = 10). For comparison purposes, we also sampled co-occurring female foragers of social Apis mellifera ( n  = 6). The samples were dissected, their DNA extracted, and gut microbiota sequenced using 16S rRNA genes. Pollen loads of A. mellifera and C. decolorata were analyzed and interactions between bee species and their plant resources were visualized using a pollination network. Results While we found the gut of A. mellifera contained the same phylotypes previously reported in the literature, we noted that the variability in the gut microbiota of solitary C. decolorata was significantly higher than that of social A. mellifera . Furthermore, the microbiota of adult C. decolorata mostly consisted of acetic acid bacteria whereas that of A. mellifera mostly had lactic acid bacteria. Among C. decolorata , we found significant differences in alpha and beta diversity between adults and their brood cell provisions (Shannon and Chao1 p  < 0.05), due to the higher abundance of families such as Rhizobiaceae and Chitinophagaceae in the brood cells, and of Acetobacteraceae in adults. In addition, the pollination network analysis indicated that A. mellifera had a stronger interaction with Byrsonima sp. and a weaker interaction with Combretaceae while interactions between C. decolorata and its plant resources were constant with the null model. Conclusion Our data are consistent with the hypothesis that behavioral differences in brood provisioning between solitary and social bees is a factor leading to relatively high variation in the microbiota of the solitary bee. 

   more » « less
2. Microclimate Temperatures Impact Nesting Preference in Megachile rotundata (Hymenoptera: Megachilidae)

   https://doi.org/10.1093/ee/nvaa012  

   Wilson, Elisabeth S; Murphy, Claire E; Rinehart, Joseph P; Yocum, George; Bowsher, Julia H; Pitts-Singer, Theresa (February 2020, Environmental Entomology)

   Abstract The temperature of the nest influences fitness in cavity-nesting bees. Females may choose nest cavities that mitigate their offspring’s exposure to stressful temperatures. This study aims to understand how cavity temperature impacts the nesting preference of the solitary bee Megachile rotundata (Fabricius) under field conditions. We designed and 3D printed nest boxes that measured the temperatures of 432 cavities. Nest boxes were four-sided with cavity entrances facing northeast, northwest, southeast, and southwest. Nest boxes were placed along an alfalfa field in Fargo, ND and were observed daily for completed nests. Our study found that cavity temperature varied by direction the cavity faced and by the position of the cavity within the nest box. The southwest sides recorded the highest maximum temperatures while the northeast sides recorded the lowest maximum temperatures. Nesting females filled cavities on the north-facing sides faster than cavities on the south-facing sides. The bees preferred to nest in cavities with lower average temperatures during foraging hours, and cavities that faced to the north. The direction the cavity faced was associated with the number of offspring per nest. The southwest-facing cavities had fewer offspring than nests on the northeast side. Our study indicates that the nesting box acts as a microclimate, with temperature varying by position and direction of the cavity. Variation in cavity temperature affected where females chose to nest, but not their reproductive investment. 

   more » « less
3. Correlated evolution of eggshell maculation with social breeding and nest type in Hirundinidae

   https://doi.org/10.1111/ibi.13118  

   Levin, Iris I.; Kaufman, Stephanie L.; Knaysi, Sophia E.; Rataezyk, Olivia G. (August 2022, Ibis)

   Maculation on avian eggshells has the potential to serve as an identity signal, and this information may help females recognize their eggs/nest or reject foreign eggs laid by hetero‐ or conspecific brood parasites. Recognizing eggs could be adaptive in cases where birds nest in dense colonies, as reports of conspecific brood parasitism are over‐represented in colony‐nesting species. We utilized the variation in breeding biology (solitary vs. colonial breeding) and eggshell phenotype in swallows and martins (Hirundinidae) to test for correlated evolution between these traits, while also accounting for nest type, as maculation may camouflage eggs in open‐cup nests. We found that maculated eggs were more likely to be laid by species that breed socially and build open‐cup nests where maculation would be more visible than in dark cavity nests. 

   more » « less
4. Developmental transcriptomes predict adult social behaviours in the socially flexible sweat bee, Lasioglossum baleicum

   https://doi.org/10.1111/mec.17244  

   Omufwoko, Kennedy_S; Cronin, Adam_L; Nguyen, Thi_Thu_Ha; Webb, Andrew_E; Traniello, Ian_M; Kocher, Sarah_D (December 2023, Molecular Ecology)

   Abstract Natural variation can provide important insights into the genetic and environmental factors that shape social behaviour and its evolution. The sweat bee,Lasioglossum baleicum, is a socially flexible bee capable of producing both solitary and eusocial nests. We demonstrate that within a single nesting aggregation, soil temperatures are a strong predictor of the social structure of nests. Sites with warmer temperatures in the spring have a higher frequency of social nests than cooler sites, perhaps because warmer temperatures provide a longer reproductive window for those nests. To identify the molecular correlates of this behavioural variation, we generated a de novo genome assembly forL. baleicum, and we used transcriptomic profiling to compare adults and developing offspring from eusocial and solitary nests. We find that adult, reproductive females have similar expression profiles regardless of social structure in the nest, but that there are strong differences between reproductive females and workers from social nests. We also find substantial differences in the transcriptomic profiles of stage‐matched pupae from warmer, social‐biased sites compared to cooler, solitary‐biased sites. These transcriptional differences are strongly predictive of adult reproductive state, suggesting that the developmental environment may set the stage for adult behaviours inL. baleicum. Together, our results help to characterize the molecular mechanisms shaping variation in social behaviour and highlight a potential role of environmental tuning during development as a factor shaping adult behaviour and physiology in this socially flexible bee. 

   more » « less
5. Biology of Andrena (Callandrena sensu lato) asteris Robertson (Hymenoptera: Andrenidae), an eastern aster specialist that makes a very deep nest

   Espinoza, A.C. (January 2023, Northeastern naturalist)

   Here we present the first description of nest architecture, immature stages, and brood-parasitism of Andrena (Callandrena s. l.) asteris (Aster Miner Bee) and the first description of the nesting biology of any Callandrena in eastern North America. Brood cells varied from 50 to 91 cm in depth, making this the deepest solitary bee nest recorded in northeastern North America. Additionally, we assembled data on soil texture, phenology, geographic distribution, and host-plant preferences. By modeling publicly available observation data, we find that areas of peak habitat suitability for A. asteris are in proximity to coastal and inland shorelines and major water courses. Our results corroborate a recent assessment of the conservation status of New York pollinators, which ranked A. asteris as “vulnerable”. 

   more » « less