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Harrap MJM, de Vere N, Hempel de Ibarra N, Whitney HM, Rands SA. Variations of floral temperature in changing weather conditions. Ecol Evol 2024; 14:e11651. [PMID: 38952664 PMCID: PMC11214831 DOI: 10.1002/ece3.11651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 06/13/2024] [Accepted: 06/14/2024] [Indexed: 07/03/2024] Open
Abstract
Floral temperature is a flower characteristic that has the potential to impact the fitness of flowering plants and their pollinators. Likewise, the presence of floral temperature patterns, areas of contrasting temperature across the flower, can have similar impacts on the fitness of both mutualists. It is currently poorly understood how floral temperature changes under the influence of different weather conditions, and how floral traits may moderate these changes. The way that floral temperature changes with weather conditions will impact how stable floral temperatures are over time and their utility to plants and pollinators. The stability of floral temperature cues is likely to facilitate effective plant-pollinator interactions and play a role in the plant's reproductive success. We use thermal imaging to monitor how floral temperatures and temperature patterns of four plant species (Cistus 'snow fire' and 'snow white', Coreopsis verticillata and Geranium psilostemon) change with several weather variables (illumination, temperature; windspeed; cloud cover; humidity and pressure) during times that pollinators are active. All weather variables influenced floral temperature in one or more species. The directionality of these relationships was similar across species. In all species, light conditions (illumination) had the greatest influence on floral temperatures overall. Floral temperature and the extent to which flowers showed contrasting temperature patterns were influenced predominantly by light conditions. However, several weather variables had additional, lesser, influences. Furthermore, differences in floral traits, pigmentation and structure, likely resulted in differences in temperature responses to given conditions between species and different parts of the same flower. However, floral temperatures and contrasting temperature patterns that are sufficiently elevated for detection by pollinators were maintained across most conditions if flowers received moderate illumination. This suggests the presence of elevated floral temperature and contrasting temperature patterns are fairly constant and may have potential to influence plant-pollinator interactions across weather conditions.
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Affiliation(s)
- Michael J. M. Harrap
- School of Biological SciencesUniversity of BristolBristolUK
- Centre for Research in Animal Behaviour, School of PsychologyUniversity of ExeterExeterUK
- Institute of Biology IAlbert‐Ludwigs‐Universität FreiburgFreiburgGermany
| | - Natasha de Vere
- Natural History Museum of DenmarkUniversity of CopenhagenCopenhagenDenmark
| | | | | | - Sean A. Rands
- School of Biological SciencesUniversity of BristolBristolUK
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2
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Fattorini R, Khojayori FN, Mellers G, Moyroud E, Herrero E, Kellenberger RT, Walker R, Wang Q, Hill L, Glover BJ. Complex petal spot formation in the Beetle Daisy (Gorteria diffusa) relies on spot-specific accumulation of malonylated anthocyanin regulated by paralogous GdMYBSG6 transcription factors. THE NEW PHYTOLOGIST 2024; 243:240-257. [PMID: 38725421 DOI: 10.1111/nph.19804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Accepted: 04/18/2024] [Indexed: 06/07/2024]
Abstract
Gorteria diffusa has elaborate petal spots that attract pollinators through sexual deception, but how G. diffusa controls spot development is largely unknown. Here, we investigate how pigmentation is regulated during spot formation. We determined the anthocyanin composition of G. diffusa petals and combined gene expression analysis with protein interaction assays to characterise R2R3-MYBs that likely regulate pigment production in G. diffusa petal spots. We found that cyanidin 3-glucoside pigments G. diffusa ray floret petals. Unlike other petal regions, spots contain a high proportion of malonylated anthocyanin. We identified three subgroup 6 R2R3-MYB transcription factors (GdMYBSG6-1,2,3) that likely activate the production of spot pigmentation. These genes are upregulated in developing spots and induce ectopic anthocyanin production upon heterologous expression in tobacco. Interaction assays suggest that these transcription factors regulate genes encoding three anthocyanin synthesis enzymes. We demonstrate that the elaboration of complex spots in G. diffusa begins with the accumulation of malonylated pigments at the base of ray floret petals, positively regulated by three paralogous R2R3-MYB transcription factors. Our results indicate that the functional diversification of these GdMYBSG6s involved changes in the spatial control of their transcription, and modification of the duration of GdMYBSG6 gene expression contributes towards floral variation within the species.
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Affiliation(s)
- Róisín Fattorini
- Department of Plant Sciences, University of Cambridge, Downing St., Cambridge, CB2 3EA, UK
- Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, UK
- Department of Biology, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK
| | - Farahnoz N Khojayori
- Department of Plant Sciences, University of Cambridge, Downing St., Cambridge, CB2 3EA, UK
| | - Gregory Mellers
- Department of Plant Sciences, University of Cambridge, Downing St., Cambridge, CB2 3EA, UK
| | - Edwige Moyroud
- Sainsbury Laboratory Cambridge University, Bateman St., Cambridge, CB2 1LR, UK
- Department of Genetics, University of Cambridge, Downing St., Cambridge, CB2 3EH, UK
| | - Eva Herrero
- Department of Plant Sciences, University of Cambridge, Downing St., Cambridge, CB2 3EA, UK
| | - Roman T Kellenberger
- Department of Plant Sciences, University of Cambridge, Downing St., Cambridge, CB2 3EA, UK
| | - Rachel Walker
- Department of Plant Sciences, University of Cambridge, Downing St., Cambridge, CB2 3EA, UK
| | - Qi Wang
- Department of Plant Sciences, University of Cambridge, Downing St., Cambridge, CB2 3EA, UK
| | - Lionel Hill
- Biomolecular Analysis Facility, John Innes Centre, Colney, Norwich, NR4 7UH, UK
| | - Beverley J Glover
- Department of Plant Sciences, University of Cambridge, Downing St., Cambridge, CB2 3EA, UK
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3
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Reeves LA, Jarvis EM, Lawson DA, Rands SA. The behavioural responses of bumblebees Bombus terrestris to simulated rain. ROYAL SOCIETY OPEN SCIENCE 2024; 11:231882. [PMID: 39076813 PMCID: PMC11285764 DOI: 10.1098/rsos.231882] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 03/28/2024] [Accepted: 04/17/2024] [Indexed: 07/31/2024]
Abstract
Bumblebee activity typically decreases during rainfall, putting them under the threat of the increased frequency of precipitation due to climate change. A novel rain machine was used within a flight arena to observe the behavioural responses of bumblebees (Bombus terrestris) to simulated rain at both a colony and individual level. During rainfall, a greater proportion of workers left the arena than entered, the opposite of which was seen during dry periods, implying that they compensate for their lack of activity when conditions improve. The proportion of workers flying and foraging decreased while resting increased in rain. This pattern reversed during dry periods, providing further evidence for compensatory activity. The increase in resting behaviour during rain is thought to evade the high energetic costs of flying while wet without unnecessarily returning to the nest. This effect was not repeated in individual time budgets, measured with lone workers, suggesting that the presence of conspecifics accelerates the decision of their behavioural response, perhaps via local enhancement. Bumblebees probably use social cues to strategize their energetic expenditure during precipitation, allowing them to compensate for the reduced foraging activity during rainfall when conditions improve.
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Affiliation(s)
- Laura A. Reeves
- School of Biological Science, University of Bristol, BristolBS8 1TQ, UK
- Centre for Agri-Environmental Research, School of Agriculture, Policy and Development, University of Reading, ReadingRG6 6AJ, UK
| | - Ellie M. Jarvis
- School of Biological Science, University of Bristol, BristolBS8 1TQ, UK
- Milner Centre for Evolution, Department of Life Sciences, University of Bath, BathBA2 7AY, UK
| | - David A. Lawson
- School of Biological Science, University of Bristol, BristolBS8 1TQ, UK
| | - Sean A. Rands
- School of Biological Science, University of Bristol, BristolBS8 1TQ, UK
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4
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Heiling JM, Koski MH. Divergent gametic thermal performance and floral warming across an elevation gradient. Evolution 2024; 78:665-678. [PMID: 38159076 DOI: 10.1093/evolut/qpad237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 12/13/2023] [Accepted: 12/29/2023] [Indexed: 01/03/2024]
Abstract
Thermal environments vary widely across species ranges, establishing the potential for local adaptation of thermal performance optima and tolerance. In the absence of local adaptation, selection should favor mechanisms to meet thermal optima. Floral temperature is a major determinant of reproductive success in angiosperms, yet whether gametic thermal performance shows signatures of local adaptation across temperature gradients, and how variation in gametic thermal performance influences floral evolution, is unknown. We characterized flowering season temperatures for the forb, Argentina anserina, at extremes of a 1000 m elevation gradient and generated thermal performance curves for pollen and ovule performance in populations at each extreme. Thermal optima fell between mean and maximum intrafloral temperatures. However, cooler high-elevation populations had ~4 °C greater pollen thermal optima than warmer low-elevation populations, while tolerance breadths did not differ. We then tested whether plants at elevational extremes differentially warmed the floral microenvironment. High-elevation flowers warmed significantly more than low, bringing intrafloral temperatures nearer the pollen optima. A manipulative experiment demonstrated that stronger warming in high elevation was conferred by floral tissues. Elevational divergence in floral warming may be driven, in part, by selection on flowers to meet different thermal demands of the gametophytes.
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Affiliation(s)
- Jacob M Heiling
- Department of Biological Sciences, Clemson University, Clemson, SC, United States
- Biology Department, Western Carolina University, Cullowhee, NC, United States
| | - Matthew H Koski
- Department of Biological Sciences, Clemson University, Clemson, SC, United States
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5
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Symington HA, Glover BJ. Strawberry varieties differ in pollinator-relevant floral traits. Ecol Evol 2024; 14:e10914. [PMID: 38322008 PMCID: PMC10844710 DOI: 10.1002/ece3.10914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 12/22/2023] [Accepted: 01/03/2024] [Indexed: 02/08/2024] Open
Abstract
A rising global population will need more food, increasing demand for insect pollination services. However, general insect declines conflict with this demand. One way to mitigate this conflict is to grow crop flowers that are easier for insects to find and more rewarding to those that visit them. This study quantifies variation in the pollinator-relevant traits of nectar and pollen production, flower size and flower shape in commercial strawberry, finding significant variation between varieties in all traits. Bumblebees could learn to distinguish between the extremes of variation in flower shape, but this learning is very slow, indicating that this variation is at the limit of that which can be detected by bumblebees. Bee preferences for nectar of differing sugar concentrations at field-realistic volumes were consistent with previous observations at larger volumes, suggesting that it is valid to translate lab findings to the field. This study builds on our knowledge of the range of pollinator reward present in a single cultivated species and of the impact of field-realistic levels of variation in floral traits on bumblebee preferences.
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6
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Rands SA, Whitney HM, Hempel de Ibarra N. Multimodal floral recognition by bumblebees. CURRENT OPINION IN INSECT SCIENCE 2023; 59:101086. [PMID: 37468044 DOI: 10.1016/j.cois.2023.101086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 07/10/2023] [Accepted: 07/13/2023] [Indexed: 07/21/2023]
Abstract
Flowers present information to their insect visitors in multiple simultaneous sensory modalities. Research has commonly focussed on information presented in visual and olfactory modalities. Recently, focus has shifted towards additional 'invisible' information, and whether information presented in multiple modalities enhances the interaction between flowers and their visitors. In this review, we highlight work that addresses how multimodality influences behaviour, focussing on work conducted on bumblebees (Bombus spp.), which are often used due to both their learning abilities and their ability to use multiple sensory modes to identify and differentiate between flowers. We review the evidence for bumblebees being able to use humidity, electrical potential, surface texture and temperature as additional modalities, and consider how multimodality enhances their performance. We consider mechanisms, including the cross-modal transfer of learning that occurs when bees are able to transfer patterns learnt in one modality to an additional modality without additional learning.
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Affiliation(s)
- Sean A Rands
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, United Kingdom.
| | - Heather M Whitney
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, United Kingdom
| | - Natalie Hempel de Ibarra
- Centre for Research in Animal Behaviour, Psychology, University of Exeter, Exeter EX4 4QG, United Kingdom
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7
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Raguso RA. Hidden worlds within flowers. Curr Biol 2023; 33:R506-R512. [PMID: 37279684 DOI: 10.1016/j.cub.2023.04.054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
There is a growing realization that ecological interactions take place at many scales, from acorns to forests, and that formerly overlooked community members, particularly microbes, can play outsized ecological roles. Beyond their primary function as the reproductive organs of angiosperms, flowers constitute resource-rich, ephemeral habitats teeming with flower-loving symbionts, or 'anthophiles'. The physical, chemical, and structural properties of flowers combine to create a habitat filter, selectively determining which anthophiles can reside there, and how, and when they interact. The microhabitats within flowers can provide shelter from predators or inclement weather, places to eat, sleep, thermoregulate, hunt, mate or reproduce. In turn, floral microhabitats contain the full range of mutualists, antagonists and apparent commensals, whose complex interactions impact how flowers look and smell, how profitable they are to foraging pollinators, and how selection feeds back upon the traits shaping those interactions. Recent studies suggest coevolutionary paths by which floral symbionts might be co-opted as mutualists and provide compelling examples in which ambush predators or florivores are recruited as floral allies. Unbiased studies that include the full roster of floral symbionts are likely to reveal novel links and additional nuance in the rich ecological communities hidden within flowers.
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Affiliation(s)
- Robert A Raguso
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA.
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8
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Salzman S, Dahake A, Kandalaft W, Valencia-Montoya WA, Calonje M, Specht CD, Raguso RA. Cone humidity is a strong attractant in an obligate cycad pollination system. Curr Biol 2023; 33:1654-1664.e4. [PMID: 37015222 DOI: 10.1016/j.cub.2023.03.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 03/06/2023] [Accepted: 03/08/2023] [Indexed: 04/05/2023]
Abstract
Studies of pollination biology often focus on visual and olfactory aspects of attraction, with few studies addressing behavioral responses and morphological adaptation to primary metabolic attributes. As part of an in-depth study of obligate nursery pollination of cycads, we find that Rhopalotria furfuracea weevils show a strong physiological response and behavioral orientation to the cone humidity of the host plant Zamia furfuracea in an equally sensitive manner to their responses to Z. furfuracea-produced cone volatiles. Our results demonstrate that weevils can perceive fine-scale differences in relative humidity (RH) and that individuals exhibit a strong behavioral preference for higher RH in binary choice assays. Host plant Z. furfuracea produces a localized cloud of higher than ambient humidity around both pollen and ovulate cones, and R. furfuracea weevils preferentially land at the zone of maximum humidity on ovulate cones, i.e., the cracks between rows of megasporophylls that provide access to the ovules. Moreover, R. furfuracea weevils exhibit striking antennal morphological traits associated with RH perception, suggesting the importance of humidity sensing in the evolution of this insect lineage. Results from this study suggest that humidity functions in a signal-like fashion in this highly specialized pollination system and help to characterize a key pollination-mediating trait in an ancient plant lineage.
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Affiliation(s)
- Shayla Salzman
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA; School of Integrative Plant Science, Section of Plant Biology and the L.H. Bailey Hortorium, Cornell University, Ithaca, NY 14853, USA.
| | - Ajinkya Dahake
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA
| | - William Kandalaft
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA
| | - Wendy A Valencia-Montoya
- Department of Organismic and Evolutionary Biology and Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA
| | | | - Chelsea D Specht
- School of Integrative Plant Science, Section of Plant Biology and the L.H. Bailey Hortorium, Cornell University, Ithaca, NY 14853, USA
| | - Robert A Raguso
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA
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James L, Reynolds AM, Mellor IR, Davies TGE. A Sublethal Concentration of Sulfoxaflor Has Minimal Impact on Buff-Tailed Bumblebee ( Bombus terrestris) Locomotor Behaviour under Aversive Conditioning. TOXICS 2023; 11:279. [PMID: 36977044 PMCID: PMC10057571 DOI: 10.3390/toxics11030279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 03/10/2023] [Accepted: 03/16/2023] [Indexed: 06/18/2023]
Abstract
Pesticide exposure has been cited as a key threat to insect pollinators. Notably, a diverse range of potential sublethal effects have been reported in bee species, with a particular focus on effects due to exposure to neonicotinoid insecticides. Here, a purpose-built thermal-visual arena was used in a series of pilot experiments to assess the potential impact of approximate sublethal concentrations of the next generation sulfoximine insecticide sulfoxaflor (5 and 50 ppb) and the neonicotinoid insecticides thiacloprid (500 ppb) and thiamethoxam (10 ppb), on the walking trajectory, navigation and learning abilities of the buff-tailed bumblebee (Bombus terrestris audax) when subjected to an aversive conditioning task. The results suggest that only thiamethoxam prevents forager bees from improving in key training parameters (speed and distanced travelled) within the thermal visual arena. Power law analyses further revealed that a speed-curvature power law, previously reported as being present in the walking trajectories of bumblebees, is potentially disrupted under thiamethoxam (10 ppb) exposure, but not under sulfoxaflor or thiacloprid exposure. The pilot assay described provides a novel tool with which to identify subtle sublethal pesticide impacts, and their potential causes, on forager bees, that current ecotoxicological tests are not designed to assess.
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Affiliation(s)
- Laura James
- Protecting Crops and the Environment, Rothamsted Research, West Common, Harpenden AL5 2JQ, UK (A.M.R.)
- Faculty of Medicine & Health Sciences, School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, UK;
| | - Andrew M. Reynolds
- Protecting Crops and the Environment, Rothamsted Research, West Common, Harpenden AL5 2JQ, UK (A.M.R.)
| | - Ian R. Mellor
- Faculty of Medicine & Health Sciences, School of Life Sciences, University of Nottingham, Nottingham NG7 2RD, UK;
| | - T. G. Emyr Davies
- Protecting Crops and the Environment, Rothamsted Research, West Common, Harpenden AL5 2JQ, UK (A.M.R.)
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10
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Karban R, Rutkowski D, Murray NA. Flowers that self-shade reduce heat stress and pollen limitation. AMERICAN JOURNAL OF BOTANY 2023; 110:e16109. [PMID: 36416006 DOI: 10.1002/ajb2.16109] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 11/12/2022] [Accepted: 11/15/2022] [Indexed: 06/16/2023]
Abstract
PREMISE Plants are facing increased risk of heat stress with global climate change. Reproductive tissues are particularly heat-sensitive, which can result in lower plant fitness. Floral shading and closure are possible mechanisms to limit heat stress although most previous work on petal orientation has considered adaptations to raise temperatures. We hypothesized that floral shading could reduce temperature and increase reproductive success. METHODS We measured floral temperatures of four species that exhibited intraspecific variation in flower closure (Opuntia ficus-indica, Oenothera elata, Convolvulus arvensis, and Romneya coulteri). We also wired newly opened R. coulteri flowers so that they were either permanently open or permanently closed; controls were not wired. RESULTS Individual flowers of all four species that shaded their pistils were exposed to temperatures 3-8°C lower than those that remained open and unshaded. In our wiring experiment, unencumbered R. coulteri controls were 40% more likely to produce seeds than flowers that were either permanently open or closed. Without added pollen, control flowers produced 2× more seeds than flowers wired open and 8× more than those wired closed. However, pollen addition eliminated the effects of wiring and increased capsule mass and seed production. This effect of pollen addition suggests that pollen limitation was responsible for observed differences in the wiring treatments. Pollinators may prefer control flowers over those that were wired open or closed; petal shading may make flowers cooler and more attractive to pollinators. CONCLUSIONS Petal shading may be a behavior that allows flowers to reduce heat stress and increases their chances of pollination and seed set.
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Affiliation(s)
- Richard Karban
- Department of Entomology and Nematology, University of California, Davis, Davis, CA, 95616, USA
| | - Danielle Rutkowski
- Department of Entomology and Nematology, University of California, Davis, Davis, CA, 95616, USA
| | - Naomi A Murray
- Department of Entomology and Nematology, University of California, Davis, Davis, CA, 95616, USA
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Kath J, Byrareddy VM, Reardon-Smith K, Mushtaq S. Early flowering changes robusta coffee yield responses to climate stress and management. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 856:158836. [PMID: 36122728 DOI: 10.1016/j.scitotenv.2022.158836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 09/13/2022] [Accepted: 09/14/2022] [Indexed: 06/15/2023]
Abstract
A shift towards earlier flowering is a widely noted consequence of climate change for the world's plants. However, whether early flowering changes the way in which plants respond to climate stress, and in turn plant yield, remains largely unexplored. Using 10 years of flowering time and yield observations (Total N = 5580) from 558 robusta coffee (Coffea canephora) farms across Vietnam we used structural equation modelling (SEM) to examine the drivers of flowering day anomalies and the consequent effects of this on coffee climate stress sensitivity and management responses (i.e. irrigation and fertilization). SEM allowed us to model the cascading and interacting effects of differences in flowering time, growing season length and climate stress. Warm nights were the main driver of early flowering (i.e. flowering day anomalies <0), which in turn corresponded to longer growing seasons. Early flowering was linked to greater sensitivity of yield to temperature during flowering (i.e. early in the season). In contrast, when late flowering occurred yield was most sensitive to temperature and rainfall later in the growing season, after flowering and fruit development. The positive effects of tree age and fertilizer on yield, apparent under late flowering conditions, were absent when flowering occurred early. Late flowering models predicted yields under early flowering conditions poorly (a 50 % reduction in cross-validated R2 of 0.54 to 0.27). Likewise, models based on early flowering were unable to predict yields well under late flowering conditions (a 75 % reduction in cross-validated R2, from 0.58 to 0.14). Our results show that early flowering changes the sensitivity of coffee production to climate stress and management and in turn our ability to predict yield. Our results indicate that changes in plant phenology need to be taken into account in order to more accurately assess climate risk and management impacts on plant performance and crop yield.
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Affiliation(s)
- Jarrod Kath
- Centre for Applied Climate Sciences, University of Southern Queensland, Toowoomba, Queensland, Australia; School of Agriculture and Environmental Science, University of Southern Queensland, Toowoomba, Queensland, Australia.
| | - Vivekananda Mittahalli Byrareddy
- Centre for Applied Climate Sciences, University of Southern Queensland, Toowoomba, Queensland, Australia; Future Drought Fund Hub (Research), University of Southern Queensland, Toowoomba, Queensland, Australia
| | - Kathryn Reardon-Smith
- Centre for Applied Climate Sciences, University of Southern Queensland, Toowoomba, Queensland, Australia; School of Agriculture and Environmental Science, University of Southern Queensland, Toowoomba, Queensland, Australia
| | - Shahbaz Mushtaq
- Centre for Applied Climate Sciences, University of Southern Queensland, Toowoomba, Queensland, Australia
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12
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Whitney HM. Ecology: Using CRISPR to switch pollinators. Curr Biol 2022; 32:R1345-R1347. [PMID: 36538885 DOI: 10.1016/j.cub.2022.11.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A single CRISPR-generated mutation in a MYB transcription factor in Petunia leads to a dual phenotype. This in turn has a dual effect on potential pollinating insects, deterring the original pollinator while increasing the visitation of a possible replacement.
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13
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Fairnie ALM, Yeo MTS, Gatti S, Chan E, Travaglia V, Walker JF, Moyroud E. Eco-Evo-Devo of petal pigmentation patterning. Essays Biochem 2022; 66:753-768. [PMID: 36205404 PMCID: PMC9750854 DOI: 10.1042/ebc20220051] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 09/09/2022] [Accepted: 09/13/2022] [Indexed: 12/13/2022]
Abstract
Colourful spots, stripes and rings decorate the corolla of most flowering plants and fulfil important biotic and abiotic functions. Spatial differences in the pigmentation of epidermal cells can create these patterns. The last few years have yielded new data that have started to illuminate the mechanisms controlling the function, formation and evolution of petal patterns. These advances have broad impacts beyond the immediate field as pigmentation patterns are wonderful systems to explore multiscale biological problems: from understanding how cells make decisions at the microscale to examining the roots of biodiversity at the macroscale. These new results also reveal there is more to petal patterning than meets the eye, opening up a brand new area of investigation. In this mini-review, we summarise our current knowledge on the Eco-Evo-Devo of petal pigmentation patterns and discuss some of the most exciting yet unanswered questions that represent avenues for future research.
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Affiliation(s)
- Alice L M Fairnie
- The Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge CB2 1LR, U.K
| | - May T S Yeo
- The Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge CB2 1LR, U.K
- Department of Genetics, Downing Site, University of Cambridge, Cambridge CB2 3EJ, U.K
| | - Stefano Gatti
- The Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge CB2 1LR, U.K
| | - Emily Chan
- The Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge CB2 1LR, U.K
| | - Valentina Travaglia
- The Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge CB2 1LR, U.K
| | - Joseph F Walker
- The Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge CB2 1LR, U.K
| | - Edwige Moyroud
- The Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge CB2 1LR, U.K
- Department of Genetics, Downing Site, University of Cambridge, Cambridge CB2 3EJ, U.K
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Harrison AS, Rands SA. The Ability of Bumblebees Bombus terrestris (Hymenoptera: Apidae) to Detect Floral Humidity is Dependent Upon Environmental Humidity. ENVIRONMENTAL ENTOMOLOGY 2022; 51:1010-1019. [PMID: 35899458 PMCID: PMC9585368 DOI: 10.1093/ee/nvac049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Indexed: 06/15/2023]
Abstract
Flowers produce local humidity that is often greater than that of the surrounding environment, and studies have shown that insect pollinators may be able to use this humidity difference to locate and identify suitable flowers. However, environmental humidity is highly heterogeneous, and is likely to affect the detectability of floral humidity, potentially constraining the contexts in which it can be used as a salient communication pathway between plants and their pollinators. In this study, we use differential conditioning techniques on bumblebees Bombus terrestris audax (Harris) to explore the detectability of an elevated floral humidity signal when presented against different levels of environmental noise. Artificial flowers were constructed that could be either dry or humid, and individual bumblebees were presented with consistent rewards in either the humid or dry flowers presented in an environment with four levels of constant humidity, ranging from low (~20% RH) to highly saturated (~95% RH). Ability to learn was dependent upon both the rewarding flower type and the environment: the bumblebees were able to learn rewarding dry flowers in all environments, but their ability to learn humid rewarding flowers was dependent on the environmental humidity, and they were unable to learn humid rewarding flowers when the environment was highly saturated. This suggests that floral humidity might be masked from bumblebees in humid environments, suggesting that it may be a more useful signal to insect pollinators in arid environments.
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Affiliation(s)
- Amy S Harrison
- School of Biological Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, United Kingdom
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15
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Nicholls E, Rands SA, Botías C, Hempel de Ibarra N. Flower sharing and pollinator health: a behavioural perspective. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210157. [PMID: 35491598 DOI: 10.1098/rstb.2021.0157] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Disease is an integral part of any organisms' life, and bees have evolved immune responses and a suite of hygienic behaviours to keep them at bay in the nest. It is now evident that flowers are another transmission hub for pathogens and parasites, raising questions about adaptations that help pollinating insects stay healthy while visiting hundreds of plants over their lifetime. Drawing on recent advances in our understanding of how bees of varying size, dietary specialization and sociality differ in their foraging ranges, navigational strategies and floral resource preferences, we explore the behavioural mechanisms and strategies that may enable foraging bees to reduce disease exposure and transmission risks at flowers by partitioning overlapping resources in space and in time. By taking a novel behavioural perspective, we highlight the missing links between disease biology and the ecology of plant-pollinator relationships, critical for improving the understanding of disease transmission risks and the better design and management of habitat for pollinator conservation. This article is part of the theme issue 'Natural processes influencing pollinator health: from chemistry to landscapes'.
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Affiliation(s)
- E Nicholls
- Evolution, Behaviour and Environment, School of Life Sciences, University of Sussex, Brighton BN1 9QG, UK
| | - S A Rands
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK
| | - C Botías
- Instituto Regional de Investigación y Desarrollo Agroalimentario y Forestal de Castilla La Mancha (IRIAF), CIAPA de Marchamalo, 19180 Guadalajara, Spain
| | - N Hempel de Ibarra
- Centre for Research in Animal Behaviour, Psychology, University of Exeter, Exeter EX4 4QG, UK
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16
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Maluf RP, Alzate-Marin AL, Silva CC, Pansarin LM, Bonifácio-Anacleto F, Schuster I, de Mello Prado R, Martinez CA. Warming and soil water availability affect plant-flower visitor interactions for Stylosanthes capitata, a tropical forage legume. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 817:152982. [PMID: 35031369 DOI: 10.1016/j.scitotenv.2022.152982] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 01/03/2022] [Accepted: 01/05/2022] [Indexed: 06/14/2023]
Abstract
The reproductive success of a zoophilous plant species depends on biological interaction with pollinators, which involves both the provision and exploitation of flower resources. Currently, there is little information about how future climate change scenarios will impact interactions between plants and their flower visitors in the tropics. This study analyzes the effects of warming and two soil water conditions on interactions between the tropical forage legume species Stylosanthes capitata and its floral visitors during the flowering period. We used a temperature-free air-controlled enhancement (T-FACE) facility to simulate future warming scenarios by increasing canopy temperature. The tested treatments were: irrigated and ambient canopy temperature (Control); non-irrigated and ambient canopy temperature (wS); irrigated and elevated canopy temperature (eT, +2 °C above ambient canopy temperature); and non-irrigated and elevated canopy temperature (wSeT). The effects of treatments on the time of flower opening and closing, sugar concentration in the nectar, and plant-flower visitor interactions were assessed. In the warmed treatments, S. capitata flower opening occurred ~45 min earlier compared to non-warmed treatments, and flowers remained opened for only ~3 h. Further, the sugar concentration in the nectar from eT was 39% higher than in the Control. The effects of warming on floral biology and flower resource production in S. capitata had an impact on the plant-floral visitor relationships with the bees Apis mellifera and Paratrigona lineata, the most abundant potential pollinating floral visitors, and the butterfly visitor Hemiargus hanno. Additionally, around noon, the interactive and additive effects of the combined wS and eT treatments decreased insect visiting frequency. These results suggest that warming and soil water deficiency could affect flower-visitor interactions and thus the reproductive success of S. capitata in tropical belts.
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Affiliation(s)
- Raquel Pérez Maluf
- Department of Natural Sciences, Semi-Arid Biodiversity Laboratory - Labisa, State University of Southwest Bahia, Estrada do Bem Querer, Km 04, UESB, 45031-900 Vitoria da Conquista, BA, Brazil
| | - Ana Lilia Alzate-Marin
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Av. Bandeirantes 3900, 14049-900 Ribeirão Preto, SP, Brazil; Department of Genetics, Graduate Program in Genetics, Ribeirão Preto Medical School, University of São Paulo, Av. Bandeirantes 3900, 14049-900 Ribeirão Preto, SP, Brazil.
| | - Carolina Costa Silva
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Av. Bandeirantes 3900, 14049-900 Ribeirão Preto, SP, Brazil
| | - Ludmila Mickeliunas Pansarin
- Department of Biology, Ribeirão Preto School of Philosophy, Science and Literature, University of São Paulo, Av. Bandeirantes 3900, 14040-901 Ribeirão Preto, SP, Brazil
| | - Fernando Bonifácio-Anacleto
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Av. Bandeirantes 3900, 14049-900 Ribeirão Preto, SP, Brazil; Department of Genetics, Graduate Program in Genetics, Ribeirão Preto Medical School, University of São Paulo, Av. Bandeirantes 3900, 14049-900 Ribeirão Preto, SP, Brazil
| | - Ivan Schuster
- Longping High-Tech, SP-330, km 296, 14140-000 Cravinhos, SP, Brazil
| | - Renato de Mello Prado
- Department of Agricultural Production Sciences, School of Agricultural and Veterinary Sciences, University of São Paulo State, Via de Acesso Prof. Paulo Donato Castellane, s/n, 14884-900 Jaboticabal, SP, Brazil
| | - Carlos A Martinez
- Department of Biology, Ribeirão Preto School of Philosophy, Science and Literature, University of São Paulo, Av. Bandeirantes 3900, 14040-901 Ribeirão Preto, SP, Brazil.
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17
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Harrap MJM, Rands SA. The role of petal transpiration in floral humidity generation. PLANTA 2022; 255:78. [PMID: 35246754 PMCID: PMC8897325 DOI: 10.1007/s00425-022-03864-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 02/22/2022] [Indexed: 05/11/2023]
Abstract
MAIN CONCLUSION Using petrolatum gel as an antitranspirant on the flowers of California poppy and giant bindweed, we show that transpiration provides a large contribution to floral humidity generation. Floral humidity, an area of elevated humidity in the headspace of flowers, is believed to be produced predominantly through a combination of evaporation of liquid nectar and transpirational water loss from the flower. However, the role of transpiration in floral humidity generation has not been directly tested and is largely inferred by continued humidity production when nectar is removed from flowers. We test whether transpiration contributes to the floral humidity generation of two species previously identified to produce elevated floral humidity, Calystegia silvatica and Eschscholzia californica. Floral humidity production of flowers that underwent an antitranspirant treatment, petrolatum gel which blocks transpiration from treated tissues, is compared to flowers that did not receive such treatments. Gel treatments reduced floral humidity production to approximately a third of that produced by untreated flowers in C. silvatica, and half of that in E. californica. This confirms the previously untested inferences that transpiration has a large contribution to floral humidity generation and that this contribution may vary between species.
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Affiliation(s)
- Michael J M Harrap
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK.
- The John Krebs Field Station, University of Oxford, Wytham, Oxford, OX2 8QJ, UK.
| | - Sean A Rands
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK.
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18
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Creux NM, Brown EA, Garner AG, Saeed S, Scher CL, Holalu SV, Yang D, Maloof JN, Blackman BK, Harmer SL. Flower orientation influences floral temperature, pollinator visits and plant fitness. THE NEW PHYTOLOGIST 2021; 232:868-879. [PMID: 34318484 DOI: 10.1111/nph.17627] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 07/06/2021] [Indexed: 06/13/2023]
Abstract
Effective insect pollination requires appropriate responses to internal and external environmental cues in both the plant and the pollinator. Helianthus annuus, a highly outcrossing species, is marked for its uniform eastward orientation of mature pseudanthia, or capitula. Here we investigate how this orientation affects floral microclimate and the consequent effects on plant and pollinator interactions and reproductive fitness. We artificially manipulated sunflower capitulum orientation and temperature in both field and controlled conditions and assessed flower physiology, pollinator visits, seed traits and siring success. East-facing capitula were found to have earlier style elongation, pollen presentation and pollinator visits compared with capitula manipulated to face west. East-facing capitula also sired more offspring than west-facing capitula and under some conditions produced heavier and better-filled seeds. Local ambient temperature change on the capitulum was found to be a key factor regulating the timing of style elongation, pollen emergence and pollinator visits. These results indicate that eastward capitulum orientation helps to control daily rhythms in floral temperature, with direct consequences on the timing of style elongation and pollen emergence, pollinator visitation, and plant fitness.
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Affiliation(s)
- Nicky M Creux
- Department of Plant Biology, University of California, One Shields Avenue, Davis, CA, 95616, USA
- Department of Plant and Soil Sciences, FABI, Innovation Africa, University of Pretoria, Lynwood Road, Hatfield, 0002, South Africa
| | - Evan A Brown
- Department of Biology, University of Virginia, PO Box 400328, Charlottesville, VA, 22904, USA
| | - Austin G Garner
- Department of Biology, University of Virginia, PO Box 400328, Charlottesville, VA, 22904, USA
| | - Sana Saeed
- Department of Plant Biology, University of California, One Shields Avenue, Davis, CA, 95616, USA
| | - C Lane Scher
- Department of Biology, University of Virginia, PO Box 400328, Charlottesville, VA, 22904, USA
| | - Srinidhi V Holalu
- Department of Plant and Microbial Biology, University of California, 111 Koshland Hall, Berkeley, CA, 94720, USA
| | - Daniel Yang
- Department of Plant and Microbial Biology, University of California, 111 Koshland Hall, Berkeley, CA, 94720, USA
| | - Julin N Maloof
- Department of Plant Biology, University of California, One Shields Avenue, Davis, CA, 95616, USA
| | - Benjamin K Blackman
- Department of Biology, University of Virginia, PO Box 400328, Charlottesville, VA, 22904, USA
- Department of Plant and Microbial Biology, University of California, 111 Koshland Hall, Berkeley, CA, 94720, USA
| | - Stacey L Harmer
- Department of Plant Biology, University of California, One Shields Avenue, Davis, CA, 95616, USA
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Hempel de Ibarra N, Rands S. Pollination: Influencing bee behaviour with caffeine. Curr Biol 2021; 31:R1090-R1092. [PMID: 34582818 DOI: 10.1016/j.cub.2021.07.073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Plant secondary metabolites found in floral nectar can affect the behaviour of pollinating insects, but how these changes benefit plants directly is little understood. An experimental study with bumblebees shows that recalling a caffeine-enhanced odour memory can increase flower visitation.
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Affiliation(s)
| | - Sean Rands
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK
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20
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Harrap MJM, Hempel de Ibarra N, Knowles HD, Whitney HM, Rands SA. Bumblebees can detect floral humidity. J Exp Biol 2021; 224:jeb240861. [PMID: 34161560 PMCID: PMC8246344 DOI: 10.1242/jeb.240861] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 05/10/2021] [Indexed: 11/20/2022]
Abstract
Floral humidity, a region of elevated humidity in the headspace of the flower, occurs in many plant species and may add to their multimodal floral displays. So far, the ability to detect and respond to floral humidity cues has been only established for hawkmoths when they locate and extract nectar while hovering in front of some moth-pollinated flowers. To test whether floral humidity can be used by other more widespread generalist pollinators, we designed artificial flowers that presented biologically relevant levels of humidity similar to those shown by flowering plants. Bumblebees showed a spontaneous preference for flowers that produced higher floral humidity. Furthermore, learning experiments showed that bumblebees are able to use differences in floral humidity to distinguish between rewarding and non-rewarding flowers. Our results indicate that bumblebees are sensitive to different levels of floral humidity. In this way floral humidity can add to the information provided by flowers and could impact pollinator behaviour more significantly than previously thought.
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Affiliation(s)
- Michael J. M. Harrap
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK
- Centre for Research in Animal Behaviour, School of Psychology, University of Exeter, Exeter, EX4 4QG, UK
| | - Natalie Hempel de Ibarra
- Centre for Research in Animal Behaviour, School of Psychology, University of Exeter, Exeter, EX4 4QG, UK
| | - Henry D. Knowles
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK
- Natural Resources Wales, Maes Newydd, Llandarcy, Neath Port Talbot, SA10 6JQ, UK
| | - Heather M. Whitney
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK
| | - Sean A. Rands
- School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK
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21
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Harrap MJM, Rands SA. Floral infrared emissivity estimates using simple tools. PLANT METHODS 2021; 17:23. [PMID: 33632239 PMCID: PMC7905901 DOI: 10.1186/s13007-021-00721-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 02/09/2021] [Indexed: 05/25/2023]
Abstract
BACKGROUND Floral temperature has important consequences for plant biology, and accurate temperature measurements are therefore important to plant research. Thermography, also referred to as thermal imaging, is beginning to be used more frequently to measure and visualize floral temperature. Accurate thermographic measurements require information about the object's emissivity (its capacity to emit thermal radiation with temperature), to obtain accurate temperature readings. However, there are currently no published estimates of floral emissivity available. This is most likely to be due to flowers being unsuitable for the most common protocols for emissivity estimation. Instead, researchers have used emissivity estimates collected on vegetative plant tissue when conducting floral thermography, assuming these tissues to have the same emissivity. As floral tissue differs from vegetative tissue, it is unclear how appropriate and accurate these vegetative tissue emissivity estimates are when they are applied to floral tissue. RESULTS We collect floral emissivity estimates using two protocols, using a thermocouple and a water bath, providing a guide for making estimates of floral emissivity that can be carried out without needing specialist equipment (apart from the thermal camera). Both protocols involve measuring the thermal infrared radiation from flowers of a known temperature, providing the required information for emissivity estimation. Floral temperature is known within these protocols using either a thermocouple, or by heating the flowers within a water bath. Emissivity estimates indicate floral emissivity is high, near 1, at least across petals. While the two protocols generally indicated the same trends, the water bath protocol gave more realistic and less variable estimates. While some variation with flower species and location on the flower is observed in emissivity estimates, these are generally small or can be explained as resulting from artefacts of these protocols, relating to thermocouple or water surface contact quality. CONCLUSIONS Floral emissivity appears to be high, and seems quite consistent across most flowers and between species, at least across petals. A value near 1, for example 0.98, is recommended for accurate thermographic measurements of floral temperature. This suggests that the similarly high values based on vegetation emissivity estimates used by previous researchers were appropriate.
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Affiliation(s)
- Michael J M Harrap
- University of Bristol, Life Sciences Building, Tyndall Ave, Bristol, BS8 1TQ, UK.
| | - Sean A Rands
- University of Bristol, Life Sciences Building, Tyndall Ave, Bristol, BS8 1TQ, UK
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22
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Rands SA, Harrap MJM. Phylogenetic signal in floral temperature patterns. BMC Res Notes 2021; 14:39. [PMID: 33509265 PMCID: PMC7844958 DOI: 10.1186/s13104-021-05455-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 01/16/2021] [Indexed: 02/01/2023] Open
Abstract
OBJECTIVES Floral structures may be warmer than their environment, and can show thermal patterning, where individual floral structures show different temperatures across their surface. Pollinators can differentiate between artificial flowers that mimic both naturally warmed and thermally patterned ones, but it has yet to be demonstrated that these patterns are biologically meaningful. To explore the relationship between pollinators and temperature patterning, we need to know whether there is diversity in patterning, and that these patterns are not simply a by-product of floral architecture constrained by ancestry. We analysed a dataset of 97 species to explore whether intrafloral temperature differences were correlated within clades (phylogenetic signal), or whether the variation seen was diverse enough to suggest that floral temperature patterns are influenced by the abiotic or pollinator-related niches to which plant species are adapted. RESULTS Some phylogenetic signal was observed, with both the Asteraceae and species of Pelargonium being more similar than expected by chance, but with other species surveyed not showing signal. The Asteraceae tend to have large temperature differences across the floral surface, which may be due to floral architecture constraints within the family. Other families show no correlation, suggesting that patterning is influenced by pollinators and the environment.
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Affiliation(s)
- Sean A Rands
- School of Biological Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol, BS8 1TQ, UK.
| | - Michael J M Harrap
- School of Biological Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol, BS8 1TQ, UK
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23
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Nocturnal pollination: an overlooked ecosystem service vulnerable to environmental change. Emerg Top Life Sci 2020; 4:19-32. [PMID: 32478390 PMCID: PMC7326339 DOI: 10.1042/etls20190134] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 05/11/2020] [Accepted: 05/12/2020] [Indexed: 12/14/2022]
Abstract
Existing assessments of the ecosystem service of pollination have been largely restricted to diurnal insects, with a particular focus on generalist foragers such as wild and honey bees. As knowledge of how these plant-pollinator systems function, their relevance to food security and biodiversity, and the fragility of these mutually beneficial interactions increases, attention is diverting to other, less well-studied pollinator groups. One such group are those that forage at night. In this review, we document evidence that nocturnal species are providers of pollination services (including pollination of economically valuable and culturally important crops, as well as wild plants of conservation concern), but highlight how little is known about the scale of such services. We discuss the primary mechanisms involved in night-time communication between plants and insect pollen-vectors, including floral scent, visual cues (and associated specialized visual systems), and thermogenic sensitivity (associated with thermogenic flowers). We highlight that these mechanisms are vulnerable to direct and indirect disruption by a range of anthropogenic drivers of environmental change, including air and soil pollution, artificial light at night, and climate change. Lastly, we highlight a number of directions for future research that will be important if nocturnal pollination services are to be fully understood and ultimately conserved.
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24
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Shi L, Nicolson SW, Yang Y, Wu J, Yan S, Wu Z. Drinking made easier: honey bee tongues dip faster into warmer and/or less viscous artificial nectar. J Exp Biol 2020; 223:jeb229799. [PMID: 32737214 DOI: 10.1242/jeb.229799] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 07/24/2020] [Indexed: 12/11/2022]
Abstract
Optimal concentrations for nectar drinking are limited by the steep increase in the viscosity of sugar solutions with concentration. However, nectar viscosity is inversely related to temperature, which suggests there are advantages to foraging from flowers that are warmer than the surrounding air. The honey bee (Apis mellifera L.) dips nectar using a hairy tongue. However, the microscopic dynamics of the tongue while the bee ingests nectar of varying concentration, viscosity and temperature are unknown. In this study, we found that honey bees respond to the variation of nectar properties by regulating dipping frequency. Through high-speed imaging, we discovered that the honey bee traps warmer sucrose solutions with a quicker tongue. The honey bee dips the warmest and most dilute solution (40°C and 25% w/w sucrose) 1.57 times as fast as the coldest and thickest solution (20°C and 45% w/w sucrose). When the viscosity of different sucrose concentrations was kept constant by adding the inert polysaccharide Tylose, honey bees dipped nectar at constant frequency. We propose a fluid mechanism model to elucidate potential effects on sucrose intake and show that higher dipping frequency can increase the volumetric and energetic intake rates by 125% and 15%, respectively. Our findings broaden insights into how honey bees adapt to foraging constraints from the perspective of tongue dynamics, and demonstrate that elevated intrafloral temperatures and lower nectar viscosity can improve the volumetric and energetic intake rates of pollinators.
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Affiliation(s)
- Lianhui Shi
- School of Aeronautics and Astronautics, Sun Yat-Sen University, Guangzhou 510006, People's Republic of China
- School of Engineering and Technology, China University of Geosciences (Beijing), Beijing 100083, People's Republic of China
| | - Susan W Nicolson
- Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa
| | - Yunqiang Yang
- School of Engineering and Technology, China University of Geosciences (Beijing), Beijing 100083, People's Republic of China
| | - Jianing Wu
- School of Aeronautics and Astronautics, Sun Yat-Sen University, Guangzhou 510006, People's Republic of China
| | - Shaoze Yan
- Division of Intelligent and Biomechanical Systems, State Key Laboratory of Tribology, Department of Mechanical Engineering, Tsinghua University, Beijing 100084, People's Republic of China
| | - Zhigang Wu
- School of Aeronautics and Astronautics, Sun Yat-Sen University, Guangzhou 510006, People's Republic of China
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25
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Multimodal interactions in insect navigation. Anim Cogn 2020; 23:1129-1141. [PMID: 32323027 PMCID: PMC7700066 DOI: 10.1007/s10071-020-01383-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 04/02/2020] [Accepted: 04/06/2020] [Indexed: 01/06/2023]
Abstract
Animals travelling through the world receive input from multiple sensory modalities that could be important for the guidance of their journeys. Given the availability of a rich array of cues, from idiothetic information to input from sky compasses and visual information through to olfactory and other cues (e.g. gustatory, magnetic, anemotactic or thermal) it is no surprise to see multimodality in most aspects of navigation. In this review, we present the current knowledge of multimodal cue use during orientation and navigation in insects. Multimodal cue use is adapted to a species’ sensory ecology and shapes navigation behaviour both during the learning of environmental cues and when performing complex foraging journeys. The simultaneous use of multiple cues is beneficial because it provides redundant navigational information, and in general, multimodality increases robustness, accuracy and overall foraging success. We use examples from sensorimotor behaviours in mosquitoes and flies as well as from large scale navigation in ants, bees and insects that migrate seasonally over large distances, asking at each stage how multiple cues are combined behaviourally and what insects gain from using different modalities.
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26
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Harrap MJM, Hempel de Ibarra N, Knowles HD, Whitney HM, Rands SA. Floral Humidity in Flowering Plants: A Preliminary Survey. FRONTIERS IN PLANT SCIENCE 2020; 11:249. [PMID: 32211004 PMCID: PMC7068853 DOI: 10.3389/fpls.2020.00249] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Accepted: 02/18/2020] [Indexed: 05/18/2023]
Abstract
The area of space immediately around the floral display is likely to have an increased level of humidity relative to the environment around it, due to both nectar evaporation and floral transpiration. This increased level of floral humidity could act as a close-distance cue for pollinators or influence thermoregulation, pollen viability and infection of flowers by fungal pathogens. However, with a few exceptions, not much is known about the patterns of floral humidity in flowering plants or the physiological traits that result in its generation. We conducted a survey of 42 radially symmetrical flower species (representing 21 widely spread families) under controlled conditions. Humidity was measured using a novel robot arm technique that allowed us to take measurements along transects across and above the floral surface. The intensity of floral humidity was found to vary between different flower species. Thirty of the species we surveyed presented levels of humidity exceeding a control comparable to background humidity levels, while twelve species did not. Patterns of floral humidity also differed across species. Nevertheless, floral humidity tended to be highest near the center of the flower, and decreased logarithmically with increasing distance above the flower, normally declining to background levels within 30 mm. It remains unclear how physiological traits influence the diversity of floral humidity discovered in this survey, but floral shape seems to also influence floral humidity. These results demonstrate that floral humidity may occur in a wide range of species and that there might be greater level of diversity and complexity in this floral trait than previously known.
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Affiliation(s)
| | - Natalie Hempel de Ibarra
- Centre for Research in Animal Behaviour, School of Psychology, University of Exeter, Exeter, United Kingdom
| | - Henry D. Knowles
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
| | - Heather M. Whitney
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
| | - Sean A. Rands
- School of Biological Sciences, University of Bristol, Bristol, United Kingdom
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27
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Rudall PJ. Colourful cones: how did flower colour first evolve? JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:759-767. [PMID: 31714579 DOI: 10.1093/jxb/erz479] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 10/14/2019] [Indexed: 05/09/2023]
Abstract
Angiosperms that are biotically pollinated typically produce flowers with bright and contrasting colours that help to attract pollinators and hence contribute to the reproductive success of the species. This colourful array contrasts with the much less multicoloured reproductive structures of the four living gymnosperm lineages, which are mostly wind pollinated, though cycads and Gnetales are predominantly pollinated by insects that feed on surface fluids from the pollination drops. This review examines the possible evolutionary pathways and cryptic clues for flower colour in both living and fossil seed plants. It investigates how the ancestral flowering plants could have overcome the inevitable trade-off that exists between attracting pollinators and minimizing herbivory, and explores the possible evolutionary and biological inferences from the colours that occur in some living gymnosperms. The red colours present in the seed-cone bracts of some living conifers result from accumulation of anthocyanin pigments; their likely primary function is to help protect the growing plant tissues under particular environmental conditions. Thus, the visual cue provided by colour in flower petals could have first evolved as a secondary effect, probably post-dating the evolution of bee colour vision but occurring before the subsequent functional accumulation of a range of different flower pigments.
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Harrap MJM, Hempel de Ibarra N, Whitney HM, Rands SA. Floral temperature patterns can function as floral guides. ARTHROPOD-PLANT INTERACTIONS 2020; 14:193-206. [PMID: 32215113 PMCID: PMC7073333 DOI: 10.1007/s11829-020-09742-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 01/03/2020] [Indexed: 05/25/2023]
Abstract
Floral guides are signal patterns that lead pollinators to floral rewards after they have located the flower, and increase foraging efficiency and pollen transfer. Patterns of several floral signalling modalities, particularly colour patterns, have been identified as being able to function as floral guides. Floral temperature frequently shows patterns that can be used by bumblebees for locating and recognising the flower, but whether these temperature patterns can function as a floral guide has not been explored. Furthermore, how combined patterns (using multiple signalling modalities) affect floral guide function has only been investigated in a few modality combinations. We assessed how artificial flowers induce behaviours in bumblebees when rewards are indicated by unimodal temperature patterns, unimodal colour patterns or multimodal combinations of these. Bees visiting flowers with unimodal temperature patterns showed an increased probability of finding rewards and increased learning of reward location, compared to bees visiting flowers without patterns. However, flowers with contrasting unimodal colour patterns showed further guide-related behavioural changes in addition to these, such as reduced reward search times and attraction to the rewarding feeder without learning. This shows that temperature patterns alone can function as a floral guide, but with reduced efficiency. When temperature patterns were added to colour patterns, bees showed similar improvements in learning reward location and reducing their number of failed visits in addition to the responses seen to colour patterns. This demonstrates that temperature pattern guides can have beneficial effects on flower handling both when alone or alongside colour patterns.
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Affiliation(s)
- Michael J. M. Harrap
- School of Biological Sciences, University of Bristol, 24 Tyndall Ave, Bristol, BS8 1TQ UK
| | | | - Heather M. Whitney
- School of Biological Sciences, University of Bristol, 24 Tyndall Ave, Bristol, BS8 1TQ UK
| | - Sean A. Rands
- School of Biological Sciences, University of Bristol, 24 Tyndall Ave, Bristol, BS8 1TQ UK
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29
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Rebolleda Gómez M, Ashman T. Floral organs act as environmental filters and interact with pollinators to structure the yellow monkeyflower (
Mimulus guttatus
) floral microbiome. Mol Ecol 2019; 28:5155-5171. [DOI: 10.1111/mec.15280] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 10/10/2019] [Accepted: 10/14/2019] [Indexed: 12/18/2022]
Affiliation(s)
| | - Tia‐Lynn Ashman
- Department of Biological Sciences University of Pittsburgh Pittsburgh PA USA
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30
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van der Kooi CJ, Kevan PG, Koski MH. The thermal ecology of flowers. ANNALS OF BOTANY 2019; 124:343-353. [PMID: 31206146 PMCID: PMC6798827 DOI: 10.1093/aob/mcz073] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 04/27/2019] [Indexed: 05/16/2023]
Abstract
BACKGROUND Obtaining an optimal flower temperature can be crucial for plant reproduction because temperature mediates flower growth and development, pollen and ovule viability, and influences pollinator visitation. The thermal ecology of flowers is an exciting, yet understudied field of plant biology. SCOPE This review focuses on several attributes that modify exogenous heat absorption and retention in flowers. We discuss how flower shape, orientation, heliotropic movements, pubescence, coloration, opening-closing movements and endogenous heating contribute to the thermal balance of flowers. Whenever the data are available, we provide quantitative estimates of how these floral attributes contribute to heating of the flower, and ultimately plant fitness. OUTLOOK Future research should establish form-function relationships between floral phenotypes and temperature, determine the fitness effects of the floral microclimate, and identify broad ecological correlates with heat capture mechanisms.
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Affiliation(s)
- Casper J van der Kooi
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands
| | - Peter G Kevan
- School of Environmental Sciences, University of Guelph, Guelph, Canada
| | - Matthew H Koski
- Department of Biology, University of Virginia, Charlottesville, VA, USA
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31
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Harrap MJM, Lawson DA, Whitney HM, Rands SA. Cross-modal transfer in visual and nonvisual cues in bumblebees. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2019; 205:427-437. [PMID: 30859258 PMCID: PMC6579774 DOI: 10.1007/s00359-019-01320-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 02/10/2019] [Accepted: 02/14/2019] [Indexed: 10/27/2022]
Abstract
Bumblebees Bombus terrestris are good at learning to distinguish between patterned flowers. They can differentiate between flowers that differ only in their patterning of scent, surface texture, temperature, or electrostatic charge, in addition to visual patterns. As recently shown, bumblebees trained to discriminate between nonvisual scent patterns can transfer this learning to visually patterned flowers that show similar spatial patterning to the learnt scent patterns. Bumblebees can, therefore, transfer learnt patterns between different sensory modalities, without needing to relearn them. We used differential conditioning techniques to explore whether cross-modal transfer of learnt patterns also occurred between visual and temperature patterns. Bumblebees that successfully learnt to distinguish rewarding and unrewarding temperature patterns did not show any preferences for the corresponding unlearnt visual pattern. Similarly, bumblebees that learnt visual patterns did not transfer these to temperature patterns, suggesting that they are unable to transfer learning of temperature and visual patterns. We discuss how cross-modality pattern learning may be limited to modalities that have potentially strong neurological links, such as the previously demonstrated transfer between scent and visual patterns.
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Affiliation(s)
- Michael J. M. Harrap
- School of Biological Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol, BS8 1TQ UK
| | - David A. Lawson
- School of Biological Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol, BS8 1TQ UK
| | - Heather M. Whitney
- School of Biological Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol, BS8 1TQ UK
| | - Sean A. Rands
- School of Biological Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol, BS8 1TQ UK
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32
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Cellini A, Giacomuzzi V, Donati I, Farneti B, Rodriguez-Estrada MT, Savioli S, Angeli S, Spinelli F. Pathogen-induced changes in floral scent may increase honeybee-mediated dispersal of Erwinia amylovora. THE ISME JOURNAL 2019; 13:847-859. [PMID: 30504898 PMCID: PMC6461938 DOI: 10.1038/s41396-018-0319-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 10/31/2018] [Accepted: 11/06/2018] [Indexed: 11/09/2022]
Abstract
Honeybees are well recognised for their key role in plant reproduction as pollinators. On the other hand, their activity may vector some pathogens, such as the bacterium Erwinia amylovora, the causative agent of fire blight disease in pomaceous plants. In this research, we evaluated whether honeybees are able to discriminate between healthy and E. amylovora-infected flowers, thus altering the dispersal of the pathogen. For this reason, honeybees were previously trained to forage either on inoculated or healthy (control) apple flower. After the training, the two honeybee groups were equally exposed to inoculated and control flowering apple plants. To assess their preference, three independent methods were used: (1) direct count of visiting bees per time frame; (2) incidence on apple flowers of a marker bacterium (Pantoea agglomerans, strain P10c) carried by foragers; (3) quantification of E. amylovora populations in the collected pollen loads, proportional to the number of visits to infected flowers. The results show that both honeybee groups preferred control flowers over inoculated ones. The characterisation of volatile compounds released by flowers revealed a different emission of several bioactive compounds, providing an explanation for honeybee preference. As an unexpected ecological consequence, the influence of infection on floral scent increasing the visit rate on healthy flowers may promote a secondary bacterial spread.
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Affiliation(s)
- Antonio Cellini
- Department of Agricultural and Food Sciences, Alma Mater Studiorum - University of Bologna, viale G. Fanin 44, Bologna, 40127, Italy
| | - Valentino Giacomuzzi
- Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza Università 5, Bolzano, 39100, Italy
| | - Irene Donati
- Department of Agricultural and Food Sciences, Alma Mater Studiorum - University of Bologna, viale G. Fanin 44, Bologna, 40127, Italy
| | - Brian Farneti
- Department of Genomics and Biology of Fruit Crops, Research and Innovation Centre, Fondazione Edmund Mach, Via E. Mach 1, S. Michele all'Adige (TN), 38010, Italy
| | - Maria T Rodriguez-Estrada
- Department of Agricultural and Food Sciences, Alma Mater Studiorum - University of Bologna, viale G. Fanin 44, Bologna, 40127, Italy
| | - Stefano Savioli
- Department of Agricultural and Food Sciences, Alma Mater Studiorum - University of Bologna, viale G. Fanin 44, Bologna, 40127, Italy
| | - Sergio Angeli
- Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza Università 5, Bolzano, 39100, Italy
| | - Francesco Spinelli
- Department of Agricultural and Food Sciences, Alma Mater Studiorum - University of Bologna, viale G. Fanin 44, Bologna, 40127, Italy.
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Aartsma Y, Cusumano A, Fernández de Bobadilla M, Rusman Q, Vosteen I, Poelman EH. Understanding insect foraging in complex habitats by comparing trophic levels: insights from specialist host-parasitoid-hyperparasitoid systems. CURRENT OPINION IN INSECT SCIENCE 2019; 32:54-60. [PMID: 31113632 DOI: 10.1016/j.cois.2018.11.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 10/09/2018] [Accepted: 11/06/2018] [Indexed: 06/09/2023]
Abstract
Insects typically forage in complex habitats in which their resources are surrounded by non-resources. For herbivores, pollinators, parasitoids, and higher level predators research has focused on how specific trophic levels filter and integrate information from cues in their habitat to locate resources. However, these insights frequently build specific theory per trophic level and seldom across trophic levels. Here, we synthesize advances in understanding of insect foraging behavior in complex habitats by comparing trophic levels in specialist host-parasitoid-hyperparasitoid systems. We argue that resources may become less apparent to foraging insects when they are member of higher trophic levels and hypothesize that higher trophic level organisms require a larger number of steps in their foraging decisions. We identify important knowledge gaps of information integration strategies by insects that belong to higher trophic levels.
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Affiliation(s)
- Yavanna Aartsma
- Wageningen University, Laboratory of Entomology, P.O. Box 16, 6700 AA Wageningen, The Netherlands
| | - Antonino Cusumano
- Wageningen University, Laboratory of Entomology, P.O. Box 16, 6700 AA Wageningen, The Netherlands
| | | | - Quint Rusman
- Wageningen University, Laboratory of Entomology, P.O. Box 16, 6700 AA Wageningen, The Netherlands
| | - Ilka Vosteen
- Wageningen University, Laboratory of Entomology, P.O. Box 16, 6700 AA Wageningen, The Netherlands
| | - Erik H Poelman
- Wageningen University, Laboratory of Entomology, P.O. Box 16, 6700 AA Wageningen, The Netherlands.
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Harrap MJM, Hempel de Ibarra N, Whitney HM, Rands SA. Reporting of thermography parameters in biology: a systematic review of thermal imaging literature. ROYAL SOCIETY OPEN SCIENCE 2018; 5:181281. [PMID: 30662737 PMCID: PMC6304129 DOI: 10.1098/rsos.181281] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 11/09/2018] [Indexed: 05/25/2023]
Abstract
Infrared (IR) thermography, where temperature measurements are made with IR cameras, has proven to be a very useful and widely used tool in biological science. Several thermography parameters are critical to the proper operation of thermal cameras and the accuracy of measurements, and these must usually be provided to the camera. Failure to account for these parameters may lead to less accurate measurements. Furthermore, the failure to provide information of parameter choices in reports may compromise appraisal of accuracy and replicate studies. In this review, we investigate how well biologists report thermography parameters. This is done through a systematic review of biological thermography literature that included articles published between years 2007 and 2017. We found that in primary biological thermography papers, which make some kind of quantitative temperature measurement, 48% fail to report values used for emissivity (an object's capacity to emit thermal radiation relative to a black body radiator), which is the minimum level of reporting that should take place. This finding highlights the need for life scientists to take into account and report key parameter information when carrying out thermography, in the future.
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Affiliation(s)
| | - Natalie Hempel de Ibarra
- Centre for Research in Animal Behaviour, School of Psychology, University of Exeter, Exeter EX4 4QG, UK
| | - Heather M. Whitney
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK
| | - Sean A. Rands
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK
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35
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Shrestha M, Garcia JE, Bukovac Z, Dorin A, Dyer AG. Pollination in a new climate: Assessing the potential influence of flower temperature variation on insect pollinator behaviour. PLoS One 2018; 13:e0200549. [PMID: 30067757 PMCID: PMC6070230 DOI: 10.1371/journal.pone.0200549] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Accepted: 06/28/2018] [Indexed: 12/04/2022] Open
Abstract
Climate change has the potential to enhance or disrupt biological systems, but currently, little is known about how organism plasticity may facilitate adaptation to localised climate variation. The bee-flower relationship is an exemplar signal-receiver system that may provide important insights into the complexity of ecological interactions in situations like this. For example, several studies on bee temperature preferences show that bees prefer to collect warm nectar from flowers at low ambient temperatures, but switch their preferences to cooler flowers at ambient temperatures above about 30° C. We used temperature sensor thermal probes to measure the temperature of outdoor flowers of 30 plant species in the Southern regions of the Australian mainland, to understand how different species could modulate petal temperature in response to changes in ambient temperature and, potentially, influence the decision-making of bees in the flowering plant's favour. We found that flower petal temperatures respond in different ways to changing ambient temperature: linearly increasing or decreasing relative to the ambient temperature, dynamically changing in a non-linear manner, or varying their temperature along with the ambient conditions. For example, our investigation of the difference between ambient temperature and petal temperature (ΔT), and ambient temperature, revealed a non-linear relationship for Erysimum linifolium and Polygala grandiflora that seems suited to bee temperature preferences. The temperature profiles of species like Hibertia vestita and H. obtusifolia appear to indicate that they do not have a cooling mechanism. These species may therefore be less attractive to bee pollinators in changing climatic conditions with ambient temperatures increasingly above 30° C. This may be to the species' detriment when insect-pollinator mediated selection is considered. However, we found no evidence that flower visual characteristics used by bees to identify flowers at close range, such as colour or shape, were straightforward modulators of floral temperature. We could not identify any clear link to phylogenetic history and temperature modulation either. Mapping our test flower distribution on the Australian continent however, indicates a potential clustering that suggests different flower responses may constitute adaptations to local conditions. Our study proposes a framework for modelling the potential effects of climate change and floral temperature on flower pollination dynamics at local and global scales.
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Affiliation(s)
- Mani Shrestha
- School of Media and Communication, RMIT University, Melbourne, Australia
- Faculty of Information Technology, Monash University, Melbourne, Australia
| | - Jair E. Garcia
- School of Media and Communication, RMIT University, Melbourne, Australia
| | - Zoë Bukovac
- Faculty of Information Technology, Monash University, Melbourne, Australia
| | - Alan Dorin
- Faculty of Information Technology, Monash University, Melbourne, Australia
| | - Adrian G. Dyer
- School of Media and Communication, RMIT University, Melbourne, Australia
- Department of Physiology, Monash University, Melbourne, Australia
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36
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Lawson DA, Chittka L, Whitney HM, Rands SA. Bumblebees distinguish floral scent patterns, and can transfer these to corresponding visual patterns. Proc Biol Sci 2018; 285:20180661. [PMID: 29899070 PMCID: PMC6015847 DOI: 10.1098/rspb.2018.0661] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 05/21/2018] [Indexed: 11/21/2022] Open
Abstract
Flowers act as multisensory billboards to pollinators by using a range of sensory modalities such as visual patterns and scents. Different floral organs release differing compositions and quantities of the volatiles contributing to floral scent, suggesting that scent may be patterned within flowers. Early experiments suggested that pollinators can distinguish between the scents of differing floral regions, but little is known about how these potential scent patterns might influence pollinators. We show that bumblebees can learn different spatial patterns of the same scent, and that they are better at learning to distinguish between flowers when the scent pattern corresponds to a matching visual pattern. Surprisingly, once bees have learnt the spatial arrangement of a scent pattern, they subsequently prefer to visit novel unscented flowers that have an identical arrangement of visual marks, suggesting that multimodal floral signals may exploit the mechanisms by which learnt information is stored by the bee.
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Affiliation(s)
- David A Lawson
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK
| | - Lars Chittka
- Department of Experimental and Biological Psychology, Queen Mary University of London, London E1 4NS, UK
| | - Heather M Whitney
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK
| | - Sean A Rands
- School of Biological Sciences, University of Bristol, Bristol BS8 1TQ, UK
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37
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Lawson DA, Rands SA. The evolution of floral guides: using a genetic algorithm to investigate the evolution of floral cue arrangements. Biol J Linn Soc Lond 2018. [DOI: 10.1093/biolinnean/bly011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- David A Lawson
- School of Biological Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol, UK
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38
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Bing J, Kessler D. Solar flower power. eLife 2017; 6. [PMID: 29257746 PMCID: PMC5736348 DOI: 10.7554/elife.33591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 12/12/2017] [Indexed: 11/28/2022] Open
Abstract
Bumblebees use invisible temperature patterns on flowers to make foraging decisions.
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Affiliation(s)
- Julia Bing
- Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Danny Kessler
- Greenhouse Department, Max Planck Institute for Chemical Ecology, Jena, Germany
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39
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Harrap MJM, Rands SA, Hempel de Ibarra N, Whitney HM. The diversity of floral temperature patterns, and their use by pollinators. eLife 2017; 6:e31262. [PMID: 29254518 PMCID: PMC5736352 DOI: 10.7554/elife.31262] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 11/14/2017] [Indexed: 11/13/2022] Open
Abstract
Pollinating insects utilise various sensory cues to identify and learn rewarding flower species. One such cue is floral temperature, created by captured sunlight or plant thermogenesis. Bumblebees, honeybees and stingless bees can distinguish flowers based on differences in overall temperature between flowers. We report here that floral temperature often differs between different parts of the flower creating a temperature structure or pattern. Temperature patterns are common, with 55% of 118 plant species thermographed, showing within-flower temperature differences greater than the 2°C difference that bees are known to be able to detect. Using differential conditioning techniques, we show that bumblebees can distinguish artificial flowers differing in temperature patterns comparable to those seen in real flowers. Thus, bumblebees are able to perceive the shape of these within-flower temperature patterns. Floral temperature patterns may therefore represent a new floral cue that could assist pollinators in the recognition and learning of rewarding flowers.
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Affiliation(s)
- Michael JM Harrap
- School of Biological SciencesUniversity of BristolBristolUnited Kingdom
| | - Sean A Rands
- School of Biological SciencesUniversity of BristolBristolUnited Kingdom
| | - Natalie Hempel de Ibarra
- Centre for Research in Animal Behaviour, School of PsychologyUniversity of ExeterExeterUnited Kingdom
| | - Heather M Whitney
- School of Biological SciencesUniversity of BristolBristolUnited Kingdom
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