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Gavini SS, Quintero C. Predation risk and floral rewards: How pollinators balance these conflicts and the consequences on plant fitness. CURRENT RESEARCH IN INSECT SCIENCE 2024; 6:100091. [PMID: 39193177 PMCID: PMC11345579 DOI: 10.1016/j.cris.2024.100091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 07/09/2024] [Accepted: 07/15/2024] [Indexed: 08/29/2024]
Abstract
Foraging behavior of pollinators is shaped by, among other factors, the conflict between maximizing resource intake and minimizing predation risk; yet, empirical studies quantifying variation in both forces are rare, compared to those investigating each separately. Here, we discuss the importance of simultaneously assessing bottom-up and top-down forces in the study of plant-pollinator interactions, and propose a conceptual and testable graphical hypothesis for pollinator foraging behavior and plant fitness outcomes as a function of varying floral rewards and predation risk. In low predation risk scenarios, no noticeable changes in pollinator foraging behavior are expected, with reward levels affecting only the activity threshold. However, as predation risk increases we propose that there is a decrease in foraging behavior, with a steeper decline as plants are more rewarding and profitable. Lastly, in high predation risk scenarios, we expect foraging to approach zero, regardless of floral rewards. Thus, we propose that pollinator foraging behavior follows an inverse S-shape curve, with more pronounced changes in foraging activity at intermediate levels of predation risk, especially in high reward systems. We present empirical evidence that is consistent with this hypothesis. In terms of the consequences for plant fitness, we propose that specialized plant-pollinator systems should be more vulnerable to increased predation risk, with a steeper and faster decline in plant fitness, compared with generalist systems, in which pollinator redundancy can delay or buffer the effect of predators. Moreover, whereas we expect that specialist systems follows a similar inverse S-shape curve, in generalist systems we propose three different scenarios as a function not only of reward level but also compatibility, mating-system, and the interplay between growth form and floral display. The incorporation of trade-offs in pollinator behavior balancing the conflicting demands between feeding and predation risk has a promising future as a key feature enabling the development of more complex foraging models.
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Affiliation(s)
- Sabrina S. Gavini
- INIBIOMA, CONICET-CRUB, Universidad Nacional del Comahue, Quintral 1250, San Carlos de Bariloche, Río Negro, Argentina
| | - Carolina Quintero
- INIBIOMA, CONICET-CRUB, Universidad Nacional del Comahue, Quintral 1250, San Carlos de Bariloche, Río Negro, Argentina
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Pimienta MC, Koptur S. More than Moths: Flower Visitors of a Night-Blooming Plant in South Florida Pine Rocklands, USA. PLANTS (BASEL, SWITZERLAND) 2022; 11:2799. [PMID: 36297823 PMCID: PMC9609400 DOI: 10.3390/plants11202799] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Revised: 10/18/2022] [Accepted: 10/19/2022] [Indexed: 06/16/2023]
Abstract
Plants whose flowers open at night but remain open during the day also attract diurnal flower visitors, potentially boosting their pollination rates and providing resources that can support diverse arthropod communities. The rough-leaf velvetseed, Guettarda scabra (Rubiaceae), is an evergreen shrub that thrives only in the imperiled pine rockland habitat in south Florida. Its white, tubular, and fragrant flowers open during late afternoon, exhibiting traits strongly associated with the attraction of nocturnal hawkmoths (Sphingidae). Flowers of G. scabra remain open until the following morning, becoming available to a wider array of visitors, bringing into question the expectation that sphingophilous flowers are visited mainly by hawkmoths. To evaluate whether the flowers of G. scabra are mainly visited by nocturnal hawkmoths and understand the role of this plant in the pine rockland habitat, we characterized the arthropod fauna associated with its flowers during the morning, evening, and at night. We found that most flower visitors were diurnal insects of the orders Hymenoptera and Lepidoptera, although we observed other arthropod groups too. Visitation at night was dominated by two species of hawkmoths. Nectar was the main resource used by the arthropod community during this study. Legitimate visitation and nectar-robbing were the behaviors most frequently observed among the flower visitors. Our results suggest that flowers of the night-blooming G. scabra constitute an important food source for both diurnal and nocturnal arthropod fauna in the fire-dependent pine rocklands of southern Florida. Our study provides novel data to support efforts to conserve and protect pine rocklands and the plants and animals that inhabit them.
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Rodríguez-Gironés MA, Jiménez OM. Encounters with predators fail to trigger predator avoidance in bumblebees, Bombus terrestris (Hymenoptera: Apidae). Biol J Linn Soc Lond 2019. [DOI: 10.1093/biolinnean/blz155] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Many species must learn to identify their predators, but little is known about the effect of direct encounters on the development of predator avoidance. We asked whether bumblebees, Bombus terrestris, learn to avoid predators, whether learning depends on the conspicuousness of predators and whether bumblebees learn to identify predators or simply to avoid dangerous patches. To answer these questions, we allowed bumblebees to forage in an enclosed meadow of 15 artificial flowers containing a yellow female crab spider, Thomisus onustus. Flowers were yellow in half of the trials and white in the other half. Spiders could remain at the same flower throughout the experiment or swap flowers between bee foraging bouts. Of the 60 bees used in the experiment, eight were killed by the spiders and nine stopped foraging without finishing the trial. Death or refusal to forage typically occurred early in the trial. Regardless of the treatment, the probability of landing at the spider-harbouring flower increased with time. Previous encounters with heterospecific individuals can therefore be a poor source of information about their predatory nature.
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Affiliation(s)
- Miguel A Rodríguez-Gironés
- Estación Experimental de Zonas Áridas, Spanish National Research Council (CSIC), Carretera de Sacrament s/n, La Cañada de San Urbano, Almeria, Spain
| | - Olga M Jiménez
- Estación Experimental de Zonas Áridas, Spanish National Research Council (CSIC), Carretera de Sacrament s/n, La Cañada de San Urbano, Almeria, Spain
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Gavini SS, Quintero C, Tadey M. Intraspecific variation in body size of bumblebee workers influences anti-predator behaviour. J Anim Ecol 2019; 89:658-669. [PMID: 31667824 DOI: 10.1111/1365-2656.13135] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 09/28/2019] [Indexed: 11/27/2022]
Abstract
Flower-dwelling predators make flowers dangerous foraging sites for pollinators, potentially affecting their anti-predator behaviour. Moreover, predation vulnerability often varies among pollinators' body sizes with interspecific comparisons showing that smaller species are more vulnerable than larger ones. However, how intraspecific body size variation influences pollinator behaviour under predation risk is still unknown, especially under natural conditions. We hypothesized that bumblebee workers of different sizes will exhibit different foraging strategies under predation risk. We predict that (a) small workers should more often exhibit anti-predator behaviours than larger workers. We also hypothesized that the anti-predator behaviour should be influenced by predator size and reward availability; therefore, we expect (b) higher avoidance behaviour towards larger predator sizes and (c) more and longer visits to inflorescences with high nectar availability. Finally, we expect that (d) nectar availability should overcome the anti-predator behaviour in less vulnerable, large, workers. We recorded flower visitation, time spent and rejection behaviours of different sizes of Bombus terrestris (Apidae) workers (large, medium and small) to inflorescences of Alstroemeria aurea (Alstroemeriaceae) with different treatments of artificial spiders (small and large) and nectar availability (with, without). Anti-predator and foraging behaviour of bumblebees was affected by the size of the worker, the presence of artificial spiders and nectar availability. Large and medium size bumblebees strongly reduced flower visitation and time spent in the presence of artificial spiders, consistently avoiding flowers with spiders, regardless of spider size or nectar availability. Instead, small bumblebees seldom modified their behaviour when facing artificial spiders, only increasing their avoidance or decreasing their foraging time in nectarless flowers hosting large artificial spiders. This pattern of larger workers being more sensitive to predation risk than smaller ones at the intraspecific level in B. terrestris is contrary to the expected and acknowledged trend based on previous interspecific comparisons, but partially consistent with predictions of models of optimal foraging theory. Intraspecific behavioural variability was uncovered only when nectar was available, whereas artificial predator size rarely modified bumblebee anti-predator and foraging behaviour. Therefore, our findings suggest that the trade-off between maximizing resource intake and minimizing predation risk strongly varies across bumblebee worker body sizes.
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Affiliation(s)
- Sabrina S Gavini
- Laboratorio Ecotono, INIBIOMA, UNComahue-CONICET, San Carlos de Bariloche, Argentina
| | - Carolina Quintero
- Laboratorio Ecotono, INIBIOMA, UNComahue-CONICET, San Carlos de Bariloche, Argentina
| | - Mariana Tadey
- Laboratorio Ecotono, INIBIOMA, UNComahue-CONICET, San Carlos de Bariloche, Argentina
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Telles FJ, Gonzálvez FG, Rodríguez-Gironés MA, Freitas L. The effect of a flower-dwelling predator on a specialized pollination system. Biol J Linn Soc Lond 2018. [DOI: 10.1093/biolinnean/bly184] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Francismeire Jane Telles
- Programa de Pós-Graduação em Ecologia e Conservação de Recursos Naturais, Universidade Federal de Uberlândia, Uberlândia - MG, Brazil
| | | | | | - Leandro Freitas
- Jardim Botânico do Rio de Janeiro, Rio de Janeiro - RJ, Brazil
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Lucas A, Bodger O, Brosi BJ, Ford CR, Forman DW, Greig C, Hegarty M, Neyland PJ, de Vere N, Sanders N. Generalisation and specialisation in hoverfly (Syrphidae) grassland pollen transport networks revealed by DNA metabarcoding. J Anim Ecol 2018; 87:1008-1021. [PMID: 29658115 PMCID: PMC6032873 DOI: 10.1111/1365-2656.12828] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 02/19/2018] [Indexed: 11/29/2022]
Abstract
Pollination by insects is a key ecosystem service and important to wider ecosystem function. Most species-level pollination networks studied have a generalised structure, with plants having several potential pollinators, and pollinators in turn visiting a number of different plant species. This is in apparent contrast to a plant's need for efficient conspecific pollen transfer. The aim of this study was to investigate the structure of pollen transport networks at three levels of biological hierarchy: community, species and individual. We did this using hoverflies in the genus Eristalis, a key group of non-Hymenopteran pollinators. We constructed pollen transport networks using DNA metabarcoding to identify pollen. We captured hoverflies in conservation grasslands in west Wales, UK, removed external pollen loads, sequenced the pollen DNA on the Illumina MiSeq platform using the standard plant barcode rbcL, and matched sequences using a pre-existing plant DNA barcode reference library. We found that Eristalis hoverflies transport pollen from 65 plant taxa, more than previously appreciated. Networks were generalised at the site and species level, suggesting some degree of functional redundancy, and were more generalised in late summer compared to early summer. In contrast, pollen transport at the individual level showed some degree of specialisation. Hoverflies defined as "single-plant visitors" varied from 40% of those captured in early summer to 24% in late summer. Individual hoverflies became more generalised in late summer, possibly in response to an increase in floral resources. Rubus fruticosus agg. and Succisa pratensis were key plant species for hoverflies at our sites Our results contribute to resolving the apparent paradox of how generalised pollinator networks can provide efficient pollination to plant species. Generalised hoverfly pollen transport networks may result from a varied range of short-term specialised feeding bouts by individual insects. The generalisation and functional redundancy of Eristalis pollen transport networks may increase the stability of the pollination service they deliver.
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Affiliation(s)
- Andrew Lucas
- Department of BiosciencesCollege of ScienceSwansea UniversitySwanseaUK
| | - Owen Bodger
- School of MedicineInstitute of Life ScienceSwansea UniversitySwanseaUK
| | - Berry J. Brosi
- Department of Environmental SciencesEmory UniversityAtlantaGAUSA
| | - Col R. Ford
- National Botanic Garden of WalesLlanarthneUK
| | - Dan W. Forman
- Department of BiosciencesCollege of ScienceSwansea UniversitySwanseaUK
| | - Carolyn Greig
- School of MedicineInstitute of Life ScienceSwansea UniversitySwanseaUK
| | | | | | - Natasha de Vere
- National Botanic Garden of WalesLlanarthneUK
- Institute of Biological, Environmental and Rural SciencesAberystwyth UniversityAberystwythUK
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Harmon‐Threatt AN, Valpine P, Kremen C. Estimating resource preferences of a native bumblebee: the effects of availability and use–availability models on preference estimates. OIKOS 2016. [DOI: 10.1111/oik.03550] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Alexandra N. Harmon‐Threatt
- Dept of Environmental Science, Policy and Management Univ. of California Berkeley Berkeley CA 94720 USA
- Dept of Entomology Univ. of Illinois, Urbana‐Champaign Urbana IL 61801 USA
| | - Perry Valpine
- Dept of Environmental Science, Policy and Management Univ. of California Berkeley Berkeley CA 94720 USA
| | - Claire Kremen
- Dept of Environmental Science, Policy and Management Univ. of California Berkeley Berkeley CA 94720 USA
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Sidhu SC, Wilson Rankin EE. Honey Bees Avoiding Ant Harassment at Flowers Using Scent Cues. ENVIRONMENTAL ENTOMOLOGY 2016; 45:420-426. [PMID: 26834187 DOI: 10.1093/ee/nvv230] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Pollinators require resources throughout the year to maintain healthy populations. Along the urban-natural interface, floral resource availability may be limited especially when the system experiences extreme drought and fire threats. In such areas, succulents, such as Aloe spp., are commonly planted to serve as functional drought-tolerant, fire-protective landscaping, which can also support pollinator populations. However, access to this resource may be restricted by competition from other floral foragers, including invasive pests. We measured free-foraging honey bee (Apis mellifera L.) visitation rate and visitation duration to aloe flowers with and without Argentine ants (Linepithema humile (Mayr)) in a drought-stressed environment and found that bees actively avoided foraging on the ant-occupied flowers. To determine the mechanisms of avoidance, our subsequent experiments assessed visitation in the absence of ants and compared aloe flowers treated with ant pheromone to unmanipulated flowers lacking ant pheromone. Bees approached all flowers equally, but accepted flowers without ants at a higher rate than flowers with ants. Visitation duration also increased twofold on ant-excluded flowers, which suggests that Argentine ants may limit resource acquisition by bees. Honey bees similarly avoided flowers with Argentine ant pheromone and preferentially visited unmanipulated flowers at threefold higher rate. This study demonstrates that honey bees avoid foraging on floral resources with invasive Argentine ants and that bees use ant odors to avoid ant-occupied flowers. Resource limitation by this invasive pest ant may have serious implication for sustaining healthy pollinator populations at the urban-natural interface.
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Affiliation(s)
- Sheena C Sidhu
- Department of Entomology, University of California, Riverside 900 University Ave, Riverside, CA 92521 (; ), and
| | - Erin E Wilson Rankin
- Department of Entomology, University of California, Riverside 900 University Ave, Riverside, CA 92521 (; ), and
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9
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The influence of the food–predation trade-off on the foraging behaviour of central-place foragers. Behav Ecol Sociobiol 2015. [DOI: 10.1007/s00265-014-1866-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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10
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Weak trophic links between a crab-spider and the effective pollinators of a rewardless orchid. ACTA OECOLOGICA 2015. [DOI: 10.1016/j.actao.2014.11.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Dupont YL, Trøjelsgaard K, Hagen M, Henriksen MV, Olesen JM, Pedersen NME, Kissling WD. Spatial structure of an individual-based plant-pollinator network. OIKOS 2014. [DOI: 10.1111/oik.01426] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Yoko L. Dupont
- Plant and Insect Ecology, Dept of Bioscience; Aarhus Univ.; Vejlsøvej 25 DK-8600 Silkeborg Denmark
| | - Kristian Trøjelsgaard
- Genetics, Ecology and Evolution, Dept of Bioscience; Aarhus Univ.; Ny Munkegade 114 DK-8000 Aarhus C Denmark
| | - Melanie Hagen
- Genetics, Ecology and Evolution, Dept of Bioscience; Aarhus Univ.; Ny Munkegade 114 DK-8000 Aarhus C Denmark
| | - Marie V. Henriksen
- School of Biological Sciences, Monash Univ.; Bld 18 Victoria 3800 Australia
| | - Jens M. Olesen
- Genetics, Ecology and Evolution, Dept of Bioscience; Aarhus Univ.; Ny Munkegade 114 DK-8000 Aarhus C Denmark
| | - Nanna M. E. Pedersen
- Genetics, Ecology and Evolution, Dept of Bioscience; Aarhus Univ.; Ny Munkegade 114 DK-8000 Aarhus C Denmark
| | - W. Daniel Kissling
- Inst. for Biodiversity and Ecosystem Dynamics (IBED), Univ. of Amsterdam; PO Box 94248 NL-1090 GE Amsterdam the Netherlands
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Mezquida ET, Benkman CW. CAUSES OF VARIATION IN BIOTIC INTERACTION STRENGTH AND PHENOTYPIC SELECTION ALONG AN ALTITUDINAL GRADIENT. Evolution 2014; 68:1710-21. [DOI: 10.1111/evo.12394] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 02/18/2014] [Indexed: 11/29/2022]
Affiliation(s)
- Eduardo T. Mezquida
- Department of Ecology; Faculty of Sciences; Autonomous University of Madrid; Madrid Spain
| | - Craig W. Benkman
- Department of Zoology and Physiology; University of Wyoming; Laramie Wyoming 82070
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Rodríguez-Gironés MA. Possible top-down control of solitary bee populations by ambush predators. Behav Ecol 2012. [DOI: 10.1093/beheco/arr228] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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