Measuring, comparing and interpreting phenotypic selection on floral scent

Natural selection on floral scent composition is a key element of the hypothesis that pollinators and other floral visitors drive scent evolution. The measure of such selection is complicated by the high-dimensional nature of floral scent data and uncertainty about the cognitive processes involved in scent-mediated communication. We use dimension reduction through reduced-rank regression to jointly estimate a scent composite trait under selection and the strength of selection acting on this trait. To assess and compare variation in selection on scent across species, time and space, we reanalyse 22 datasets on six species from four previous studies. The results agreed qualitatively with previous analyses in terms of identifying populations and scent compounds subject to stronger selection but also allowed us to evaluate and compare the strength of selection on scent across studies. Doing so revealed that selection on floral scent was highly variable, and overall about as common and as strong as selection on other phenotypic traits involved in pollinator attraction or pollen transfer. These results are consistent with an important role of floral scent in pollinator attraction. Our approach should be useful for further studies of plant-animal communication and for studies of selection on other high-dimensional phenotypes. In particular, our approach will be useful for studies of pollinator-mediated selection on complex scent blends comprising many volatiles, and when no prior information on the physiological responses of pollinators to scent compounds is available

Measuring, comparing and interpreting phenotypic selection on floral scent

Natural selection on floral scent composition is a key element of the hypothesis that pollinators and other floral visitors drive scent evolution. The measure of such selection is complicated by the high-dimensional nature of floral scent data and uncertainty about the cognitive processes involved in scent-mediated communication. We use dimension reduction through reduced-rank regression to jointly estimate a scent composite trait under selection and the strength of selection acting on this trait. To assess and compare variation in selection on scent across species, time and space, we reanalyse 22 datasets on six species from four previous studies. The results agreed qualitatively with previous analyses in terms of identifying populations and scent compounds subject to stronger selection but also allowed us to evaluate and compare the strength of selection on scent across studies. Doing so revealed that selection on floral scent was highly variable, and overall about as common and as strong as selection on other phenotypic traits involved in pollinator attraction or pollen transfer. These results are consistent with an important role of floral scent in pollinator attraction. Our approach should be useful for further studies of plant-animal communication and for studies of selection on other high-dimensional phenotypes. In particular, our approach will be useful for studies of pollinator-mediated selection on complex scent blends comprising many volatiles, and when no prior information on the physiological responses of pollinators to scent compounds is available.Peer reviewe

Evolutionary Ecology of Floral Traits in Fragrant Orchids

Why are flowers so diverse? Much of floral evolution is thought to be driven by pollinator-mediated selection. However, the connection between macroevolutionary patterns of floral diversity and microevolutionary processes remains poorly understood. In this thesis, I have used the fragrant orchids Gymnadenia conopsea s.s. and Gymnadenia densiflora to investigate the role of pollinators as agents of selection on floral traits and to test whether they cause spatial variation in selection. I addressed the following questions (1) Is there divergent selection on flowering phenology and floral traits between these two closely related species? (2) What is the contribution of pollinators relative to other selective agents to selection on phenology, visual display, floral scent and spur length? (3) Do diurnal and nocturnal pollinators mediate different selection patterns? (4) Does spatial variation in pollinator communities cause spatial variation in selection? A phenotypic selection study in G. conopsea s.s. and G. densiflora indicated that divergent selection on flowering time contributes to the maintenance of phenological differentiation between the two species. Hand-pollination experiments combined with selection analysis showed that while pollinators were the main selective agent on spur length, their contribution to selection on phenology, visual display and floral scent was more variable and sometimes opposed by non-pollinator mediated selection. Selection analyses combined with a selective exclusion experiment showed that diurnal and nocturnal pollinators exerted different selection patterns on floral traits. Hand-pollination experiments also demonstrated that variation in pollinator-mediated selection largely explained spatial variation in net selection on phenology, visual display and spur length among four populations. A study of floral scent emission of G. conopsea s.s. in the field coupled with a growth-chamber experiment revealed genetically-based variation in floral scent consistent with a scenario where spatial variation in relative importance of nocturnal and diurnal pollinators has resulted in the evolution of different scent emission rhythms. Taken together, the results support the hypothesis that pollinators cause spatial variation in selection on floral traits. They also highlight the importance of experimentally identifying sources of selection to reveal conflicting and reinforcing selection by multiple agents and thus advance our understanding of the evolutionary ecology of floral traits

Evolutionary Ecology of Floral Traits in Fragrant Orchids

Why are flowers so diverse? Much of floral evolution is thought to be driven by pollinator-mediated selection. However, the connection between macroevolutionary patterns of floral diversity and microevolutionary processes remains poorly understood. In this thesis, I have used the fragrant orchids Gymnadenia conopsea s.s. and Gymnadenia densiflora to investigate the role of pollinators as agents of selection on floral traits and to test whether they cause spatial variation in selection. I addressed the following questions (1) Is there divergent selection on flowering phenology and floral traits between these two closely related species? (2) What is the contribution of pollinators relative to other selective agents to selection on phenology, visual display, floral scent and spur length? (3) Do diurnal and nocturnal pollinators mediate different selection patterns? (4) Does spatial variation in pollinator communities cause spatial variation in selection? A phenotypic selection study in G. conopsea s.s. and G. densiflora indicated that divergent selection on flowering time contributes to the maintenance of phenological differentiation between the two species. Hand-pollination experiments combined with selection analysis showed that while pollinators were the main selective agent on spur length, their contribution to selection on phenology, visual display and floral scent was more variable and sometimes opposed by non-pollinator mediated selection. Selection analyses combined with a selective exclusion experiment showed that diurnal and nocturnal pollinators exerted different selection patterns on floral traits. Hand-pollination experiments also demonstrated that variation in pollinator-mediated selection largely explained spatial variation in net selection on phenology, visual display and spur length among four populations. A study of floral scent emission of G. conopsea s.s. in the field coupled with a growth-chamber experiment revealed genetically-based variation in floral scent consistent with a scenario where spatial variation in relative importance of nocturnal and diurnal pollinators has resulted in the evolution of different scent emission rhythms. Taken together, the results support the hypothesis that pollinators cause spatial variation in selection on floral traits. They also highlight the importance of experimentally identifying sources of selection to reveal conflicting and reinforcing selection by multiple agents and thus advance our understanding of the evolutionary ecology of floral traits

Evolutionary Ecology of Floral Traits in Fragrant Orchids

Why are flowers so diverse? Much of floral evolution is thought to be driven by pollinator-mediated selection. However, the connection between macroevolutionary patterns of floral diversity and microevolutionary processes remains poorly understood. In this thesis, I have used the fragrant orchids Gymnadenia conopsea s.s. and Gymnadenia densiflora to investigate the role of pollinators as agents of selection on floral traits and to test whether they cause spatial variation in selection. I addressed the following questions (1) Is there divergent selection on flowering phenology and floral traits between these two closely related species? (2) What is the contribution of pollinators relative to other selective agents to selection on phenology, visual display, floral scent and spur length? (3) Do diurnal and nocturnal pollinators mediate different selection patterns? (4) Does spatial variation in pollinator communities cause spatial variation in selection? A phenotypic selection study in G. conopsea s.s. and G. densiflora indicated that divergent selection on flowering time contributes to the maintenance of phenological differentiation between the two species. Hand-pollination experiments combined with selection analysis showed that while pollinators were the main selective agent on spur length, their contribution to selection on phenology, visual display and floral scent was more variable and sometimes opposed by non-pollinator mediated selection. Selection analyses combined with a selective exclusion experiment showed that diurnal and nocturnal pollinators exerted different selection patterns on floral traits. Hand-pollination experiments also demonstrated that variation in pollinator-mediated selection largely explained spatial variation in net selection on phenology, visual display and spur length among four populations. A study of floral scent emission of G. conopsea s.s. in the field coupled with a growth-chamber experiment revealed genetically-based variation in floral scent consistent with a scenario where spatial variation in relative importance of nocturnal and diurnal pollinators has resulted in the evolution of different scent emission rhythms. Taken together, the results support the hypothesis that pollinators cause spatial variation in selection on floral traits. They also highlight the importance of experimentally identifying sources of selection to reveal conflicting and reinforcing selection by multiple agents and thus advance our understanding of the evolutionary ecology of floral traits

Selection analysis data

Data on morphological traits, scent traits, and fitness for all individual Gymnadenia conopsea plants included in the study

Divergent selection on flowering phenology but not on floral morphology between two closely related orchids

Closely related species often differ in traits that influence reproductive success, suggesting that divergent selection on such traits contribute to the maintenance of species boundaries. Gymnadenia conopsea ss. and Gymnadenia densiflora are two closely related, perennial orchid species that differ in (a) floral traits important for pollination, including flowering phenology, floral display, and spur length, and (b) dominant pollinators. If plant–pollinator interactions contribute to the maintenance of trait differences between these two taxa, we expect current divergent selection on flowering phenology and floral morphology between the two species. We quantified phenotypic selection via female fitness in one year on flowering start, three floral display traits (plant height, number of flowers, and corolla size) and spur length, in six populations of G. conopsea s.s. and in four populations of G. densiflora. There was indication of divergent selection on flowering start in the expected direction, with selection for earlier flowering in two populations of the early‐flowering G. conopsea s.s. and for later flowering in one population of the late‐flowering G. densiflora. No divergent selection on floral morphology was detected, and there was no significant stabilizing selection on any trait in the two species. The results suggest ongoing adaptive differentiation of flowering phenology, strengthening this premating reproductive barrier between the two species. Synthesis: This study is among the first to test whether divergent selection on floral traits contribute to the maintenance of species differences between closely related plants. Phenological isolation confers a substantial potential for reproductive isolation, and divergent selection on flowering time can thus greatly influence reproductive isolation and adaptive differentiation

Data from: Conflicting selection on floral scent emission in the orchid Gymnadenia conopsea

• Floral scent is a crucial trait for pollinator attraction. Yet, only a handful of studies have estimated selection on scent in natural populations and no study has quantified the relative importance of pollinators versus other agents of selection.• In the fragrant orchid Gymnadenia conopsea s.s., we used electroantennographic data to identify floral scent compounds detected by local pollinators and quantified pollinator-mediated selection on emission rates of ten target compounds as well as on flowering start, visual display and spur length.• Nocturnal pollinators contributed more to reproductive success than diurnal pollinators, but there was significant pollinator-mediated selection on both diurnal and nocturnal scent emission. Pollinators selected for increased emission of two compounds and reduced emission of two other compounds, of which none were major constituents of the total bouquet. In three cases, pollinator-mediated selection was opposed by non-pollinator-mediated selection, leading to weaker or non-detected net selection.• Our study demonstrates that minor scent compounds can be targets of selection, that pollinators do not necessarily favour strong scent signalling, and that some scent compounds are subject to conflicting selection from pollinators and other agents of selection. Hence, including floral scent traits into selection analysis is important for understanding the mechanisms behind floral evolution

Etanercept may induce neurosarcoidosis in a patient treated for rheumatoid arthritis.

International audienceBACKGROUND: TNFα blockers have drastically improved rheumatoid arthritis prognosis by preventing joint destruction in DMARD resistant patients. Altering cytokine balance in immune diseases may expose to paradoxical adverse events. CASE PRESENTATION: We present the case of a 40-year-old woman, with a confirmed erosive and seropositive RA, successfully treated by TNFα blocker (etanercept) for seven years, and who developed a severe neurosarcoidosis. She had lymphocytic meningitis, bilateral peripheral facial paralysis and anosmia, associated with bilateral hilar lymph nodes, papilloedema, anterior uveitis and elevated serum angiotensin-converting enzyme level. Magnetic resonance imaging showed a bilateral thickening of the Gasser's ganglia walls and enhanced signal of the vestibulocochlear, the facial and the proximal portion of trijeminal nerves. CONCLUSION: This case raised the issue of the imputability of etanercept in the development of neurosarcoidosis. Neurological symptoms onset in patients on TNFα blockers should lead to exclude infections, induced lupus but also paradoxical neurosarcoidosis

När kan ekologisk kompensation bidra till att bevara biologisk mångfald och ekosystemtjänster? : Slutrapport

Om ekologisk kompensation ska kunna bidra till att hindra förlusten av biologisk mångfald och ekosystemtjänster krävs god kunskap om faktorer som främjar respektive hindrar att kompensationsåtgärder är effektiva. Vi har gjort två olika litteratursynteser som handlar om detta: 1) En syntes av vetenskapliga studier som utvärderar ekologisk kompensation, och 2) En syntes av vetenskapliga studier som utvärderar naturvårdsrestaureringar (vilket är en vanlig form av ekologisk kompensation), som utförts i andra sammanhang än ekologisk kompensation. Vi fann endast 40 vetenskapliga studier från hela världen som utvärderade effekter av ekologisk kompensation på biologisk mångfald eller ekosystemtjänster. Endast en av dessa var utformad så att man kunde avgöra om kompensationen har hindrat att det skett någon nettoförlust av biologisk mångfald. Den vanligaste typen av kompensation som utvärderades i dessa studier var nyskapande av biotoper. Majoriteten av studierna var utförda i våtmarker eller sötvattensmiljöer i Nordamerika, och det är därför svårt att dra generella slutsatser som går att tillämpa på andra naturtyper och i andra delar av världen. Det verkar dock som att det är svårare, eller tar längre tid, att kompensera ekosystemtjänster än biologisk mångfald. Vår syntes av 93 vetenskapliga studier som utvärderat restaureringsåtgärder genom att jämföra både före och efter restaurering samt med kontrollmiljöer utan åtgärder, visade på stor variation i utfall. Naturvårdsrestaureringar leder långt ifrån alltid till högre biologisk mångfald. Effekten av restaurering skiljde sig inte tydligt mellan de studerade ekosystemen skog, gräsmarker, våtmarker och sandmarker, och inte heller mellan olika organismgrupper. Däremot verkar effekten av restaureringen ta längre tid i skogsmiljöer än i gräsmarker och våtmarker. Inom respektive typ av ekosystem fanns skillnader mellan specifika restaureringsåtgärder, och i flera fall var effekten bättre när man utfört en kombination av åtgärder än effekten av dessa åtgärder för sig. För att kunna bedöma under vilka förutsättningar restaurering på en plats kan vara en effektiv åtgärd för att kompensera naturvärden som förlorats på en annan plats är det viktigt att förstå bättre vad den stora variationen i utfall beror på. Tyvärr fanns det alltför få studier för att möjliggöra en utvärdering av potentiella synergier eller avvägningar mellan olika mål med restaureringar, som mellan biologisk mångfald och ekosystemtjänster. Framtida studier bör därför belysa sådana potentiella synergier eller avvägningar. Vår syntes visar att: Det finns stora kunskapsluckor kring hur väl ekologisk kompensation hindrar förlusten av biologisk mångfald och ekosystemtjänster. Det är därför ännu inte möjligt att ta fram evidensbaserade riktlinjer för hur ekologisk kompensation bör utformas. Innan kunskap finns bör inte ekologisk kompensation användas storskaligt som medel för att hindra förlusten av biologisk mångfald. När man utformar kompensationsåtgärder är det viktigt att använda ekologisk kunskap. Även om antalet utvärderingar av ekologisk kompensation är litet kan man få god vägledning från andra typer av ekologiska undersökningar. För att kunna utvärdera vilka kompensationsåtgärder som förhindrar nettoförluster av biologisk mångfald och ekosystemtjänster behöver myndigheter som begär ekologisk kompensation samtidigt kräva en systematisk och långsiktig uppföljning av utfallet av kompensationen.If ecological compensation (biodiversity offsetting) is going to be an important tool for halting the loss of biodiversity and ecosystem services, we need solid knowledge on the factors that promote or impede effective compensation actions. We have conducted two separate literature syntheses about this: 1) A synthesis of scientific peer-reviewed studies that evaluate the effect of ecological compensation on biodiversity or ecosystem services, and 2) A synthesis of scientific studies that evaluate biodiversity restoration actions (a common form of compensation), performed in other contexts than ecological compensation. We found only 40 scientific studies worldwide that assessed the effects of ecological compensation on biodiversity or ecosystem services. Only one of these was designed in a way that it was possible to evaluate if no net loss of biodiversity was achieved. The most frequent type of compensation that was evaluated in these studies was creation of habitats. The majority of studies was performed in wetland or freshwater habitats in North America. It is therefore difficult to draw any general conclusions that are applicable in other ecosystems and in other parts of the world. It appeared, however, more difficult – or at least taking longer time – to compensate for ecosystem services than for biodiversity. Our synthesis of 93 scientific BACI (before-after-control-impact) studies of biodiversity restoration actions showed a large variation in outcomes. Restoration actions do far from always result in higher biodiversity. The effect of restoration did not differ between forest, grassland, wetland, and sandy ecosystems, or between groups of species. However, the positive effect of restoration appeared to take longer time in forest than in grassland and wetland habitats. Within each ecosystem type, there were differences between specific types of restoration actions, and combinations of actions appeared to have a more positive effect than each of these actions alone. In order to draw conclusions for ecological compensation, it is important to understand the causes of the large variability in outcomes. Without this understanding, it is not possible to evaluate under what circumstances restoration of a habitat at one site can compensate for lost biodiversity or other values at another site. Unfortunately there were too few studies to evaluate potential synergies or trade-offs between restoration targets such as between restoring biodiversity or ecosystem services. Future studies should aim at assessing when such potential synergies and trade-offs might occur. Our synthesis shows that: There are large knowledge gaps regarding how well ecological compensation can achieve the goal of not net loss of biodiversity or ecosystem services. Therefore, it is not yet possible to develop evidence-based guidelines on how to design ecological compensation actions. Until evidence exists, ecological compensation should not be applied at a large scale as a measure to halt the loss of biodiversity.  When ecological compensation is used it is, however, important to use general ecological knowledge and draw conclusions from other types of scientific ecology literature when designing compensation actions. To be able to identify compensation actions that achieve no net loss of biodiversity or ecosystem services, authorities that demand ecological compensation also need to demand systematic and long-term monitoring of the outcome of these compensation actions