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Animal-pollinated angiosperms have evolved a variety of signalling mechanisms to attract pollinators. Floral scent is a key component of pollinator attraction, and its chemistry modulates both ...pollinator behaviour and the formation of plant-pollinator networks. The neotropical orchid genus Gongora exhibits specialized pollinator associations with male orchid bees (Euglossini). Male bees visit orchid flowers to collect volatile chemical compounds that they store in hind-leg pouches to use subsequently during courtship display. Hence, Gongora floral scent compounds simultaneously serve as signalling molecules and pollinator rewards. Furthermore, because floral scent acts as the predominant reproductive isolating barrier among lineages, it has been hypothesized that chemical traits are highly species specific. A comparative analysis of intra- and inter-specific variation of floral scent chemistry was conducted to investigate the evolutionary patterns across the genus. •
Gas chromatography-mass spectrometry (GC-MS) was used to analyse the floral scent of 78 individuals belonging to 28 different species of Gongora from two of the three major lineages sampled across the neotropical region. Multidimensional scaling and indicator value analyses were implemented to investigate the patterns of chemical diversity within and among taxonomic groups at various geographic scales. Additionally, pollinator observations were conducted on a sympatric community of Gongora orchids exhibiting distinct floral scent phenotypes. •
A total of 83 floral volatiles, mainly terpenes and aromatic compounds, were detected. Many of the identified compounds are common across diverse angiosperm families (e.g. cineole, eugenol, β-ocimene, β-pinene and terpinen-4-ol), while others are relatively rare outside euglossine bee-pollinated orchid lineages. Additionally, 29 volatiles were identified that are known to attract and elicit collection behaviour in male bees. Floral scent traits were less variable within species than between species, and the analysis revealed exceptional levels of cryptic diversity. Gongora species were divided into 15 fragrance groups based on shared compounds. Fragrance groups indicate that floral scent variation is not predicted by taxonomic rank or biogeographic region. •
Gongora orchids emit a diverse array of scent molecules that are largely species specific, and closely related taxa exhibit qualitatively and quantitatively divergent chemical profiles. It is shown that within a community, Gongora scent chemotypes are correlated with near non-overlapping bee pollinator assemblies. The results lend support to the hypothesis that floral scent traits regulate the architecture of bee pollinator associations. Thus, Gongora provides unique opportunities to examine the interplay between floral traits and pollinator specialization in plant-pollinator mutualisms.
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BFBNIB, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Animals frequently evolve unique suites of traits on islands, but whether plants evolve comparable island syndromes remains unresolved. Here, we test the prediction on the basis of natural history ...observations that insect-pollinated plants evolve smaller flowers on islands than on mainland communities. We examined 556 plant species representing 136 phylogenetically independent contrasts between island and mainland sister taxa. We focused on endemic taxa originating from the Americas associated with seven tropical and subtropical islands of the Pacific Ocean. Contrary to conventional wisdom, flowers were not on average smaller on islands than on the mainland. On specific archipelagos (the Galápagos Islands and Revillagigedo Islands), however, island taxa did evolve smaller flowers. Divergence in flower size between island and mainland taxa also varied among taxonomic families, such that some plant families evolved smaller flowers on islands, other families evolved larger flowers on islands, and some families exhibited no divergence in flower size between island and mainland taxa. Overall, our results show that there is no general island syndrome for flower size, but instead that the evolution of floral morphology is complex and context dependent, depending on variation among islands and plant families. Our results also suggest that if island floras are typically dominated by small flowered species, as suggested by natural history observations, then ecological filtering is a more likely explanation of this pattern than evolutionary divergence postcolonization. We propose future studies that could disentangle the relative roles of ecological filtering and evolution in the distribution of floral traits on islands.
Abstract
Background
Nasopharyngeal specimens (NPS) are commonly used for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing but can be uncomfortable for patients. Self-collected ...saliva specimens (SS) or anterior nasal specimens (ANS) for SARS-CoV-2 detection are less invasive, but the sensitivity of these specimen types has not been thoroughly evaluated.
Methods
During September–November 2020, 730 adults undergoing SARS-CoV-2 testing at community testing events and homeless shelters in Denver provided self-collected SS and ANS before NPS collection and answered a short survey about symptoms and specimen preference. Specimens were tested for SARS-CoV-2 by means of real-time reverse-transcription polymerase chain reaction (rRT-PCR); viral culture was performed on a subset of specimens positive by rRT-PCR. The sensitivity of SS and ANS for SARS-CoV-2 detection by rRT-PCR was measured against that of NPS. Subgroup analyses included test outcomes by symptom status and culture results.
Results
Sensitivity for SARS-CoV-2 detection by rRT-PCR appeared higher for SS than for ANS (85% vs 80%) and higher among symptomatic participants than among those without symptoms (94% vs 29% for SS; 87% vs 50% for ANS). Among participants with culture-positive SARS-CoV-2 by any specimen type, the sensitivities of SS and ANS by rRT-PCR were 94% and 100%, respectively. SS and ANS were equally preferred by participants; most would undergo NPS collection again despite this method’s being the least preferred.
Conclusions
SS were slightly more sensitive than ANS for SARS-CoV-2 detection with rRT-PCR. With both SS and ANS, SARS-CoV-2 was reliably detected among participants with symptoms. Self-collected SS and ANS offer practical advantages, are preferred by patients, and might be most useful for testing people with coronavirus disease 2019 symptoms.
The family Orchidaceae exhibits some of the most diverse and intricate modes of animal pollination across angiosperms. Highly specialized pollination by male euglossine bees (Apidae, Euglossini) ...occurs in more than 600 species of Neotropical orchids. Male euglossine bees acquire volatile compounds from both floral and nonfloral sources, which they store in their specialized hind tibiae and later expose during courtship display. Euglossine-pollinated Orchidaceae produce large quantities of floral scent, which serves as both the attractant and reward for male euglossine bees. Upon collecting floral volatiles and aided by the intricate orchid floral morphology, male bees remove and subsequently deposit orchid pollinaria, resulting in pollination. Among euglossine-pollinated Orchidaceae is the species-rich genus Gongora Ruiz & Pav., which provides exceptional opportunities to investigate the evolution of scent-mediated pollinator specialization. Here we review the taxonomy, systematics, and pollination biology of Gongora. We also describe a new physical mechanism of pollination observed for Gongora and discuss the significance of different modes of pollinaria attachment in an evolutionary framework. This work provides the foundation for future research on the evolution of specialized plant-pollinator mutualisms, including elucidating the evolutionary relationships of cryptic species, understanding the evolution of floral adaptations, and investigating the mechanisms of speciation.
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The family Orchidaceae exhibits some of the most diverse and intricate modes of animal pollination across angiosperms. Highly specialized pollination by male euglossine bees (Apidae, Euglossini) ...occurs in more than 600 species of Neotropical orchids. Male euglossine bees acquire volatile compounds from both floral and nonfloral sources, which they store in their specialized hind tibiae and later expose during courtship display. Euglossine-pollinated Orchidaceae produce large quantities of floral scent, which serves as both the attractant and reward for male euglossine bees. Upon collecting floral volatiles and aided by the intricate orchid floral morphology, male bees remove and subsequently deposit orchid pollinaria, resulting in pollination. Among euglossine-pollinated Orchidaceae is the species-rich genus Gongora Ruiz & Pav., which provides exceptional opportunities to investigate the evolution of scent-mediated pollinator specialization. Here we review the taxonomy, systematics, and pollination biology of Gongora. We also describe a new physical mechanism of pollination observed for Gongora and discuss the significance of different modes of pollinaria attachment in an evolutionary framework. This work provides the foundation for future research on the evolution of specialized plant-pollinator mutualisms, including elucidating the evolutionary relationships of cryptic species, understanding the evolution of floral adaptations, and investigating the mechanisms of speciation.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
To assess the household secondary infection risk (SIR) of B.1.1.7 (Alpha) and non-Alpha lineages of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) among children.
During January to ...April 2021, we prospectively followed households with a SARS-CoV-2 infection. We collected questionnaires, serial nasopharyngeal swabs for reverse transcription polymerase chain reaction testing and whole genome sequencing, and serial blood samples for serology testing. We calculated SIRs by primary case age (pediatric vs adult), household contact age, and viral lineage. We evaluated risk factors associated with transmission and described symptom profiles among children.
Among 36 households with pediatric primary cases, 21 (58%) had secondary infections. Among 91 households with adult primary cases, 51 (56%) had secondary infections. SIRs among pediatric and adult primary cases were 45% and 54%, respectively (OR, 0.79; 95% CI, 0.41-1.54). SIRs among pediatric primary cases with Alpha and non-Alpha lineage were 55% and 46%, respectively (OR, 1.52; 95% CI, 0.51-4.53). SIRs among pediatric and adult household contacts were 55% and 49%, respectively (OR, 1.01; 95% CI, 0.68-1.50). Among pediatric contacts, no significant differences in the odds of acquiring infection by demographic or household characteristics were observed.
Household transmission of SARS-CoV-2 from children and adult primary cases to household members was frequent. The risk of secondary infection was similar among child and adult household contacts. Among children, household transmission of SARS-CoV-2 and the risk of secondary infection was not influenced by lineage. Continued mitigation strategies (eg, masking, physical distancing, vaccination) are needed to protect at-risk groups regardless of virus lineage circulating in communities.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The family Orchidaceae exhibits some of the most diverse and intricate modes of animal pollination across angiosperms. Highly specialized pollination by male euglossine bees (Apidae, Euglossini) ...occurs in more than 600 species of Neotropical orchids. Male euglossine bees acquire volatile compounds from both floral and nonfloral sources, which they store in their specialized hind tibiae and later expose during courtship display. Euglossine-pollinated Orchidaceae produce large quantities of floral scent, which serves as both the attractant and reward for male euglossine bees. Upon collecting floral volatiles and aided by the intricate orchid floral morphology, male bees remove and subsequently deposit orchid pollinaria, resulting in pollination. Among euglossine-pollinated Orchidaceae is the species-rich genus Gongora Ruiz & Pav., which provides exceptional opportunities to investigate the evolution of scent-mediated pollinator specialization. Here we review the taxonomy, systematics, and pollination biology of Gongora. We also describe a new physical mechanism of pollination observed for Gongora and discuss the significance of different modes of pollinaria attachment in an evolutionary framework. This work provides the foundation for future research on the evolution of specialized plant–pollinator mutualisms, including elucidating the evolutionary relationships of cryptic species, understanding the evolution of floral adaptations, and investigating the mechanisms of speciation.
Full text
Available for:
BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
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