uu.seUppsala University Publications
Change search
Link to record
Permanent link

Direct link
BETA
Sletvold, Nina
Publications (10 of 31) Show all publications
Caruso, C. M., Eisen, K. E., Martin, R. A. & Sletvold, N. (2019). A meta-analysis of the agents of selection on floral traits. Evolution, 73(1), 4-14
Open this publication in new window or tab >>A meta-analysis of the agents of selection on floral traits
2019 (English)In: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 73, no 1, p. 4-14Article in journal (Refereed) Published
Abstract [en]

Floral traits are hypothesized to evolve primarily in response to selection by pollinators. However, selection can also be mediated by other environmental factors. To understand the relative importance of pollinator-mediated selection and its variation among trait and pollinator types, we analyzed directional selection gradients on floral traits from experiments that manipulated the environment to identify agents of selection. Pollinator-mediated selection was stronger than selection by other biotic factors (e.g., herbivores), but similar in strength to selection by abiotic factors (e.g., soil water), providing partial support for the hypothesis that floral traits evolve primarily in response to pollinators. Pollinator-mediated selection was stronger on pollination efficiency traits than on other trait types, as expected if efficiency traits affect fitness via interactions with pollinators, but other trait types also affect fitness via other environmental factors. In addition to varying among trait types, pollinator-mediated selection varied among pollinator taxa: selection was stronger when bees, long-tongued flies, or birds were the primary visitors than when the primary visitors were Lepidoptera or multiple animal taxa. Finally, reducing pollinator access to flowers had a relatively small effect on selection on floral traits, suggesting that anthropogenic declines in pollinator populations would initially have modest effects on floral evolution.

Place, publisher, year, edition, pages
WILEY, 2019
Keywords
Floral evolution, natural selection, pollination efficiency, pollinator attraction, pollinator-mediated selection
National Category
Evolutionary Biology Ecology
Identifiers
urn:nbn:se:uu:diva-375850 (URN)10.1111/evo.13639 (DOI)000455523300001 ()30411337 (PubMedID)
Available from: 2019-02-01 Created: 2019-02-01 Last updated: 2019-02-01Bibliographically approved
Chapurlat, E., Ågren, J., Anderson, J., Friberg, M. & Sletvold, N. (2019). Conflicting selection on floral scent emission in the orchid Gymnadenia conopsea. New Phytologist, 222(4), 2009-2022
Open this publication in new window or tab >>Conflicting selection on floral scent emission in the orchid Gymnadenia conopsea
Show others...
2019 (English)In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 222, no 4, p. 2009-2022Article in journal (Refereed) Published
Abstract [en]

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 and other agents of selection. In the fragrant orchid Gymnadenia conopsea, we used electroantennographic data to identify floral scent compounds detected by local pollinators and quantified pollinator-mediated selection on emission rates of 10 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, none of which were major constituents of the total bouquet. In three cases, pollinator-mediated selection was opposed by nonpollinator-mediated selection, leading to weaker or no detectable net selection. Our study demonstrates that minor scent compounds can be targets of selection, that pollinators do not necessarily favour stronger 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.

Keywords
agents of selection, conflicting selection, diurnal and nocturnal scent emission, floral evolution, floral scent, pollinator-mediated selection, volatile organic compounds
National Category
Evolutionary Biology Ecology
Identifiers
urn:nbn:se:uu:diva-384056 (URN)10.1111/nph.15747 (DOI)000467301100029 ()30767233 (PubMedID)
Funder
Lars Hierta Memorial FoundationSwedish Research Council FormasSwedish Research Council
Available from: 2019-06-20 Created: 2019-06-20 Last updated: 2019-06-20Bibliographically approved
Parachnowitsch, A. L., Manson, J. S. & Sletvold, N. (2019). Evolutionary ecology of nectar. Annals of Botany, 123(2), 247-261
Open this publication in new window or tab >>Evolutionary ecology of nectar
2019 (English)In: Annals of Botany, ISSN 0305-7364, E-ISSN 1095-8290, Vol. 123, no 2, p. 247-261Article, review/survey (Refereed) Published
Abstract [en]

Background: Floral nectar is an important determinant of plant–pollinator interactions and an integral component of pollination syndromes, suggesting it is under pollinator-mediated selection. However, compared to floral display traits, we know little about the evolutionary ecology of nectar. Combining a literature review with a meta-analysis approach, we summarize the evidence for heritable variation in nectar traits and link this variation to pollinator response and plant fitness. We further review associations between nectar traits and floral signals and discuss them in the context of honest signalling and targets of selection.

Scope: Although nectar is strongly influenced by environmental factors, heritable variation in nectar production rate has been documented in several populations (mean h2 = 0.31). Almost nothing is known about heritability of other nectar traits, such as sugar and amino acid concentrations. Only a handful of studies have quantified selection on nectar traits, and few find statistically significant selection. Pollinator responses to nectar traits indicate they may drive selection, but studies tying pollinator preferences to plant fitness are lacking. So far, only one study conclusively identified pollinators as selective agents on a nectar trait, and the role of microbes, herbivores, nectar robbers and abiotic factors in nectar evolution is largely hypothetical. Finally, there is a trend for positive correlations among floral cues and nectar traits, indicating honest signalling of rewards.

Conclusions: Important progress can be made by studies that quantify current selection on nectar in natural populations, as well as experimental approaches that identify the target traits and selective agents involved. Signal–reward associations suggest that correlational selection may shape evolution of nectar traits, and studies exploring these more complex forms of natural selection are needed. Many questions about nectar evolution remain unanswered, making this a field ripe for future research.

Place, publisher, year, edition, pages
Oxford University Press, 2019
Keywords
Agents of selection, floral traits, heritability, honest signalling, meta-analysis, natural selection, nectar, signal–reward correlation
National Category
Evolutionary Biology
Identifiers
urn:nbn:se:uu:diva-372991 (URN)10.1093/aob/mcy132 (DOI)000462548600002 ()30032269 (PubMedID)
Available from: 2019-01-10 Created: 2019-01-10 Last updated: 2019-05-21Bibliographically approved
Trunschke, J., Sletvold, N. & Ågren, J. (2019). The independent and combined effects of floral traits distinguishing two pollination ecotypes of a moth-pollinated orchid. Ecology and Evolution, 9(3), 1191-1201
Open this publication in new window or tab >>The independent and combined effects of floral traits distinguishing two pollination ecotypes of a moth-pollinated orchid
2019 (English)In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 9, no 3, p. 1191-1201Article in journal (Refereed) Published
Abstract [en]

Identifying traits and agents of selection involved in local adaptation is important for understanding population divergence. In southern Sweden, the moth-pollinated orchid Platanthera bifolia occurs as a woodland and a grassland ecotype that differ in dominating pollinators. The woodland ecotype is taller (expected to influence pollinator attraction) and produces flowers with longer spurs (expected to influence efficiency of pollen transfer) compared to the grassland ecotype. We examined whether plant height and spur length affect pollination and reproductive success in a woodland population, and whether effects are non-additive, as expected for traits influencing two multiplicative components of pollen transfer. We reduced plant height and spur length to match trait values observed in the grassland ecotype and determined the effects on pollen removal, pollen receipt, and fruit production. In addition, to examine the effects of naturally occurring variation, we quantified pollinator-mediated selection through pollen removal and seed production in the same population. Reductions of plant height and spur length decreased pollen removal, number of flowers receiving pollen, mean pollen receipt per pollinated flower, and fruit production per plant, but no significant interaction effect was detected. The selection analysis demonstrated pollinator-mediated selection for taller plants via female fitness. However, there was no current selection mediated by pollinators on spur length, and pollen removal was not related to plant height or spur length. The results show that, although both traits are important for pollination success and female fitness in the woodland habitat, only plant height was sufficiently variable in the study population for current pollinator-mediated selection to be detected. More generally, the results illustrate how a combination of experimental approaches can be used to identify both traits and agents of selection.

National Category
Ecology
Research subject
Biology with specialization in Ecological Botany
Identifiers
urn:nbn:se:uu:diva-349138 (URN)10.1002/ece3.4808 (DOI)000461112200022 ()30805152 (PubMedID)
Funder
Swedish Research CouncilSwedish Research Council Formas
Available from: 2018-04-24 Created: 2018-04-24 Last updated: 2019-04-10Bibliographically approved
Tye, M. R., Dahlgren, J., Øien, D.-I., Moen, A. & Sletvold, N. (2018). Demographic responses to climate variation depend on spatial- and life history-differentiation at multiple scales. Biological Conservation, 228, 62-69
Open this publication in new window or tab >>Demographic responses to climate variation depend on spatial- and life history-differentiation at multiple scales
Show others...
2018 (English)In: Biological Conservation, ISSN 0006-3207, E-ISSN 1873-2917, Vol. 228, p. 62-69Article in journal (Refereed) Published
Abstract [en]

Long-term demographic data are needed for detailed viability analyses of populations threatened by climate change, but the infeasibility of obtaining such data makes it urgent to assess whether demographic responses to climatic variation can be generalized across populations and species. We used 32 years of demographic data on four species of closely related orchids (genera Dactylorhiza and Gymnadenia), replicated in a coastal and an inland region in central Norway, to test how demographic responses to climate varied among geographical regions and species. We fit generalized linear mixed models (GLMMs) to study climate effects on vital rates and included GLMMs as components in matrix models to examine climate effects on population dynamics. We found that, overall, vital rates and population growth rates of the eight populations responded independently to variation in both temperature and rainfall. Only probability of flowering showed expected regional differentiation in response to climate, despite notable regional climatic differences. Other vital rate climate relationships were structured by species or a combination of both region and species. The weak clustering of demographic responses to climate variation by species and region demonstrates that effects of climatic variation can strongly depend on variation in local habitat and life history, even among closely related populations occupying similar niches. This highlights the difficulty in transferring data from closely related and/or located populations for viability analyses and for models predicting range shifts, and a general need to account for among-population variation in demographic responses to develop successful conservation and management plans.

National Category
Ecology
Identifiers
urn:nbn:se:uu:diva-372992 (URN)10.1016/j.biocon.2018.10.005 (DOI)000452815200008 ()
Funder
Swedish Research Council Formas, 2010-644The Research Council of Norway
Available from: 2019-01-10 Created: 2019-01-10 Last updated: 2019-01-10Bibliographically approved
Chapurlat, E., Anderson, J., Ågren, J., Friberg, M. & Sletvold, N. (2018). Diel pattern of floral scent emission matches the relative importance of diurnal and nocturnal pollinators in populations of Gymnadenia conopsea. Annals of Botany, 121, 711-721
Open this publication in new window or tab >>Diel pattern of floral scent emission matches the relative importance of diurnal and nocturnal pollinators in populations of Gymnadenia conopsea
Show others...
2018 (English)In: Annals of Botany, ISSN 0305-7364, E-ISSN 1095-8290, Vol. 121, p. 711-721Article in journal (Refereed) Published
Abstract [en]

Background and Aims

Floral scent is considered an integral component of pollination syndromes, and its composition and timing of emission are thus expected to match the main pollinator type and time of activity. While floral scent differences among plant species with different pollination systems can be striking, studies on intraspecific variation are sparse, which limits our understanding of the role of pollinators in driving scent divergence.

Methods

Here, we used dynamic headspace sampling to quantify floral scent emission and composition during the day and at night in the natural habitat of six Scandinavian populations of the fragrant orchid Gymnadenia conopsea. We tested whether diel scent emission and composition match pollinator type by comparing four populations in southern Sweden, where nocturnal pollinators are more important for plant reproductive success than are diurnal pollinators, with two populations in central Norway, where the opposite is true. To determine to what extent scent patterns quantified in the field reflected plasticity, we also measured scent emission in a common growth chamber environment.

Key Results

Both scent composition and emission rates differed markedly between day and night, but only the latter varied significantly among populations. The increase in scent emission rate at night was considerably stronger in the Swedish populations compared with the Norwegian populations. These patterns persisted when plants were transferred to a common environment, suggesting a genetic underpinning of the scent variation.

Conclusions

The results are consistent with a scenario where spatial variation in relative importance of nocturnal and diurnal pollinators has resulted in selection for different scent emission rhythms. Our study highlights the importance of adding a characterization of diel variation of scent emission rates to comparative studies of floral scent, which so far have often focused on scent composition only.

Keywords
diel variation, diurnal and nocturnal pollination, floral evolution, floral scent, geographic variation, Gymnadenia conopsea (fragrant orchid), plasticity, population differentiation, scent emission rate, scent rhythm, semi-generalkized pollination, spatial variation
National Category
Evolutionary Biology Ecology
Identifiers
urn:nbn:se:uu:diva-358243 (URN)10.1093/aob/mcx203 (DOI)000427884200015 ()29360931 (PubMedID)
Funder
Swedish Research Council FormasSwedish Research Council
Available from: 2018-08-26 Created: 2018-08-26 Last updated: 2019-06-28Bibliographically approved
Shefferson, R. P., Kull, T., Hutchings, M. J., Selosse, M.-A., Jacquemyn, H., Kellett, K. M., . . . Whigham, D. F. (2018). Drivers of vegetative dormancy across herbaceous perennial plant species. Ecology Letters, 21(5), 724-733
Open this publication in new window or tab >>Drivers of vegetative dormancy across herbaceous perennial plant species
Show others...
2018 (English)In: Ecology Letters, ISSN 1461-023X, E-ISSN 1461-0248, Vol. 21, no 5, p. 724-733Article in journal (Refereed) Published
Abstract [en]

Vegetative dormancy, that is the temporary absence of aboveground growth for 1year, is paradoxical, because plants cannot photosynthesise or flower during dormant periods. We test ecological and evolutionary hypotheses for its widespread persistence. We show that dormancy has evolved numerous times. Most species displaying dormancy exhibit life-history costs of sprouting, and of dormancy. Short-lived and mycoheterotrophic species have higher proportions of dormant plants than long-lived species and species with other nutritional modes. Foliage loss is associated with higher future dormancy levels, suggesting that carbon limitation promotes dormancy. Maximum dormancy duration is shorter under higher precipitation and at higher latitudes, the latter suggesting an important role for competition or herbivory. Study length affects estimates of some demographic parameters. Our results identify life historical and environmental drivers of dormancy. We also highlight the evolutionary importance of the little understood costs of sprouting and growth, latitudinal stress gradients and mixed nutritional modes.

Place, publisher, year, edition, pages
WILEY, 2018
Keywords
Adaptation, Asteraceae, bet-hedging, demography, herbivory, latitudinal gradient, Ophioglossaceae, Orchidaceae, stress
National Category
Evolutionary Biology Botany
Identifiers
urn:nbn:se:uu:diva-352565 (URN)10.1111/ele.12940 (DOI)000430120400013 ()29575384 (PubMedID)
Available from: 2018-08-08 Created: 2018-08-08 Last updated: 2018-08-08Bibliographically approved
Siepielski, A. M., Morrissey, M. B., Buoro, M., Carlson, S. M., Caruso, C. M., Clegg, S. M., . . . MacColl, A. D. C. (2018). Response to Comment on "Precipitation drives global variation in natural selection". Science, 359(6374), Article ID eaan5760.
Open this publication in new window or tab >>Response to Comment on "Precipitation drives global variation in natural selection"
Show others...
2018 (English)In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 359, no 6374, article id eaan5760Article in journal, Editorial material (Other academic) Published
Abstract [en]

The comment by Myers-Smith and Myers focuses on three main points: (i) the lack of a mechanistic explanation for climate-selection relationships, (ii) the appropriateness of the climate data used in our analysis, and (iii) our focus on estimating climate-selection relationships across (rather than within) taxonomic groups. We address these critiques in our response.

Place, publisher, year, edition, pages
AMER ASSOC ADVANCEMENT SCIENCE, 2018
National Category
Evolutionary Biology
Identifiers
urn:nbn:se:uu:diva-350111 (URN)10.1126/science.aan5760 (DOI)000423283200002 ()
Available from: 2018-05-07 Created: 2018-05-07 Last updated: 2018-05-07Bibliographically approved
Trunschke, J., Sletvold, N. & Ågren, J. (2017). Interaction intensity and pollinator-mediated selection. New Phytologist, 214(3), 1381-1389
Open this publication in new window or tab >>Interaction intensity and pollinator-mediated selection
2017 (English)In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 214, no 3, p. 1381-1389Article in journal (Refereed) Published
Abstract [en]

In animal-pollinated plants, the opportunity for selection and the strength of pollinatormediated selection are expected to increase with the degree of pollen limitation. However, whether differences in pollen limitation can explain variation in pollinator-mediated and net selection among animal-pollinated species is poorly understood. In the present study, we quantified pollen limitation, variance in relative fitness and pollinator- mediated selection on five traits important for pollinator attraction (flowering start, plant height, flower number, flower size) and pollination efficiency (spur length) in natural populations of 12 orchid species. Pollinator-mediated selection was quantified by subtracting estimates of selection gradients for plants receiving supplemental hand-pollination from estimates obtained for open-pollinated control plants. Mean pollen limitation ranged from zero to 0.96. Opportunity for selection, pollinatormediated selection and net selection were all positively related to pollen limitation, whereas nonpollinator-mediated selection was not. Opportunity for selection varied five-fold, strength of pollinator-mediated selection varied three-fold and net selection varied 1.5-fold among species. Supplemental hand-pollination reduced both opportunity for selection and selection on floral traits. The results show that the intensity of biotic interactions is an important determinant of the selection regime, and indicate that the potential for pollinator-mediated selection and divergence in floral traits is particularly high in species that are strongly pollen-limited.

Keywords
biotic interactions, natural selection, opportunity for selection, Orchidaceae, pollen limitation, pollinator-mediated selection
National Category
Evolutionary Biology Ecology
Identifiers
urn:nbn:se:uu:diva-326362 (URN)10.1111/nph.14479 (DOI)000402403900041 ()28240377 (PubMedID)
Funder
Swedish Research CouncilSwedish Research Council Formas
Available from: 2017-07-10 Created: 2017-07-10 Last updated: 2018-04-24Bibliographically approved
Siepielski, A. M., Morrissey, M. B., Buoro, M., Carlson, S. M., Caruso, C. M., Clegg, S. M., . . . MacColl, A. D. C. (2017). Precipitation drives global variation in natural selection. Science, 355(6328), 959-962
Open this publication in new window or tab >>Precipitation drives global variation in natural selection
Show others...
2017 (English)In: Science, ISSN 0036-8075, E-ISSN 1095-9203, Vol. 355, no 6328, p. 959-962Article in journal (Refereed) Published
Abstract [en]

Climate change has the potential to affect the ecology and evolution of every species on Earth. Although the ecological consequences of climate change are increasingly well documented, the effects of climate on the key evolutionary process driving adaptation-natural selection-are largely unknown. We report that aspects of precipitation and potential evapotranspiration, along with the North Atlantic Oscillation, predicted variation in selection across plant and animal populations throughout many terrestrial biomes, whereas temperature explained little variation. By showing that selection was influenced by climate variation, our results indicate that climate change may cause widespread alterations in selection regimes, potentially shifting evolutionary trajectories at a global scale.

National Category
Biological Sciences
Identifiers
urn:nbn:se:uu:diva-318929 (URN)10.1126/science.aag2773 (DOI)000395181700041 ()28254943 (PubMedID)
Available from: 2017-04-05 Created: 2017-04-05 Last updated: 2017-11-29Bibliographically approved
Organisations

Search in DiVA

Show all publications