1
|
Rico-Guevara A, Sustaita D, Hurme KJ, Hanna JE, Jung S, Field DJ. Upper bill bending as an adaptation for nectar feeding in hummingbirds. J R Soc Interface 2024; 21:20240286. [PMID: 39601640 PMCID: PMC11601124 DOI: 10.1098/rsif.2024.0286] [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: 04/29/2024] [Revised: 08/27/2024] [Accepted: 10/15/2024] [Indexed: 11/29/2024] Open
Abstract
Observations of maxillary (upper bill) bending in hummingbirds have been considered an optical illusion, yet a recent description of out-of-phase opening and closing between their bill base and tip suggests a genuine capacity for bill bending. We investigate bill kinematics during nectar feeding in six species of hummingbirds. We employed geometric morphometrics to identify bending zones and combined these data with measurements of bill flexural rigidity from micro-computed tomography scans to better understand the flexing mechanism. We found that the mandible remains in place throughout the licking cycle, while the maxilla undergoes significant shape deformation, such that the distal portion of the upper bill bends upwards. We propose that bill bending is a key component of the drinking mechanism in hummingbirds, allowing the coordination of bill function (distal wringing and basal expansion) and tongue function (raking/squeegeeing) during intra-oral transport. We present a fluid analysis that reveals a combination of pressure-driven (Poiseuille) and boundary-driven (Couette) flows, which have previously been thought to represent alternative drinking mechanisms. Bill bending allows for separation of the bill tips while maintaining a tightly closed middle section of the bill, enabling nectar exploitation in long and narrow flowers that can exclude less efficient pollinators.
Collapse
Affiliation(s)
- Alejandro Rico-Guevara
- Department of Biology, University of Washington, Seattle, WA98195, USA
- Burke Museum of Natural History and Culture, University of Washington, Seattle, WA98195, USA
| | - Diego Sustaita
- Department of Biological Sciences, California State University San Marcos, 333 S. Twin Oaks Valley Rd, San Marcos, CA92096, USA
| | | | - Jenny E. Hanna
- Independent Researcher, Babraham, CambridgeshireCB22 3AG, UK
| | - Sunghwan Jung
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, NY14850, USA
| | - Daniel J. Field
- Department of Earth Sciences, University of Cambridge, CambridgeCB2 3EQ, UK
- Museum of Zoology, University of Cambridge, CambridgeCB2 3EJ, UK
| |
Collapse
|
2
|
Ornelas JF. Sex‐specific flower resource use in hummingbird communities. J Anim Ecol 2022; 91:2158-2162. [DOI: 10.1111/1365-2656.13789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 07/22/2022] [Indexed: 11/06/2022]
|
3
|
Rosas-Espinoza VC, Rivas M, Contreras-Martínez S, Medina J, Santiago-Pérez AL. Notes on Mexican Woodnymph (Eupherusa ridgwayi) Behavior and Nesting in Central-western Mexico. AMERICAN MIDLAND NATURALIST 2022. [DOI: 10.1674/0003-0031-187.2.258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Verónica Carolina Rosas-Espinoza
- Universidad de Guadalajara, Centro Universitario de Ciencias Biológicas y Agropecuarias, Camino Ing. Ramón Padilla Sánchez No. 2100, Zapopan, Jalisco, C.P. 45200, México
| | - Mónica Rivas
- Proyecto Nebulosa, Jardín Botánico Haravéri, La Estancia de Landeros, camino a Las Guacas km 8.5, San Sebastián del Oeste, Jalisco, C.P. 46995, México
| | - Sarahy Contreras-Martínez
- Universidad de Guadalajara, Centro Universitario de la Costa Sur, Ave. Independencia Nacional 151, Autlán de Navarro, Jalisco, C.P. 48900 México
| | - Jeshael Medina
- Proyecto Nebulosa, Jardín Botánico Haravéri, La Estancia de Landeros, camino a Las Guacas km 8.5, San Sebastián del Oeste, Jalisco, C.P. 46995, México
| | - Ana Luisa Santiago-Pérez
- Universidad de Guadalajara, Centro Universitario de Ciencias Biológicas y Agropecuarias, Camino Ing. Ramón Padilla Sánchez No. 2100, Zapopan, Jalisco, C.P. 45200, México
| |
Collapse
|
4
|
Leimberger KG, Dalsgaard B, Tobias JA, Wolf C, Betts MG. The evolution, ecology, and conservation of hummingbirds and their interactions with flowering plants. Biol Rev Camb Philos Soc 2022; 97:923-959. [PMID: 35029017 DOI: 10.1111/brv.12828] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 12/06/2021] [Accepted: 12/08/2021] [Indexed: 01/14/2023]
Abstract
The ecological co-dependency between plants and hummingbirds is a classic example of a mutualistic interaction: hummingbirds rely on floral nectar to fuel their rapid metabolisms, and more than 7000 plant species rely on hummingbirds for pollination. However, threats to hummingbirds are mounting, with 10% of 366 species considered globally threatened and 60% in decline. Despite the important ecological implications of these population declines, no recent review has examined plant-hummingbird interactions in the wider context of their evolution, ecology, and conservation. To provide this overview, we (i) assess the extent to which plants and hummingbirds have coevolved over millions of years, (ii) examine the mechanisms underlying plant-hummingbird interaction frequencies and hummingbird specialization, (iii) explore the factors driving the decline of hummingbird populations, and (iv) map out directions for future research and conservation. We find that, despite close associations between plants and hummingbirds, acquiring evidence for coevolution (versus one-sided adaptation) is difficult because data on fitness outcomes for both partners are required. Thus, linking plant-hummingbird interactions to plant reproduction is not only a major avenue for future coevolutionary work, but also for studies of interaction networks, which rarely incorporate pollinator effectiveness. Nevertheless, over the past decade, a growing body of literature on plant-hummingbird networks suggests that hummingbirds form relationships with plants primarily based on overlapping phenologies and trait-matching between bill length and flower length. On the other hand, species-level specialization appears to depend primarily on local community context, such as hummingbird abundance and nectar availability. Finally, although hummingbirds are commonly viewed as resilient opportunists that thrive in brushy habitats, we find that range size and forest dependency are key predictors of hummingbird extinction risk. A critical direction for future research is to examine how potential stressors - such as habitat loss and fragmentation, climate change, and introduction of non-native plants - may interact to affect hummingbirds and the plants they pollinate.
Collapse
Affiliation(s)
- Kara G Leimberger
- Forest Biodiversity Research Network, Department of Forest Ecosystems and Society, Oregon State University, 3100 SW Jefferson Way, Corvallis, OR, 97331, U.S.A
| | - Bo Dalsgaard
- Center for Macroecology, Evolution and Climate, GLOBE Institute, University of Copenhagen, Universitetsparken 15, Copenhagen Ø, 2100, Denmark
| | - Joseph A Tobias
- Department of Life Sciences, Imperial College London, Silwood Park, Buckhurst Road, Ascot, Berkshire, SL5 7PY, U.K
| | - Christopher Wolf
- Forest Biodiversity Research Network, Department of Forest Ecosystems and Society, Oregon State University, 3100 SW Jefferson Way, Corvallis, OR, 97331, U.S.A
| | - Matthew G Betts
- Forest Biodiversity Research Network, Department of Forest Ecosystems and Society, Oregon State University, 3100 SW Jefferson Way, Corvallis, OR, 97331, U.S.A
| |
Collapse
|
5
|
Boehm MMA, Jankowski JE, Cronk QCB. Plant-Pollinator Specialization: Origin and Measurement of Curvature. Am Nat 2021; 199:206-222. [DOI: 10.1086/717677] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Mannfred M. A. Boehm
- Department of Botany, University of British Columbia, 3156-6270 University Boulevard, Vancouver, British Columbia V6T 1Z4, Canada
- Biodiversity Research Centre, University of British Columbia, 2212 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Jill E. Jankowski
- Biodiversity Research Centre, University of British Columbia, 2212 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada
- Department of Zoology, University of British Columbia, 4200-6270 University Boulevard, Vancouver, British Columbia V6T 1Z4, Canada
| | - Quentin C. B. Cronk
- Department of Botany, University of British Columbia, 3156-6270 University Boulevard, Vancouver, British Columbia V6T 1Z4, Canada
- Biodiversity Research Centre, University of British Columbia, 2212 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada
| |
Collapse
|
6
|
Almeida JM, Missagia CCC, Alves MAS. Effects of the availability of floral resources and neighboring plants on nectar robbery in a specialized pollination system. Curr Zool 2021; 68:541-548. [PMID: 36324535 PMCID: PMC9616065 DOI: 10.1093/cz/zoab083] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 10/07/2021] [Indexed: 12/28/2022] Open
Abstract
Many plants pollinated by nectar-foraging animals have to maintain a balance between legitimate visitor attraction strategies and mechanisms that minimize illegitimate visits. This study investigated how floral display and neighboring species composition influences nectar robbing by hummingbirds in the tropical ornithophilous herb Heliconia spathocircinata. We tested the role of inflorescence display, flower abundance, and neighboring species in the reduction of nectar robbing in H. spathocircinata. Our results indicate that nectar robbing hummingbird activity was higher in moderately large inflorescence displays and that the frequency of nectar robbing in H. spathocircinata decreases with increased flower abundance and the presence of neighboring plant species. Neighboring non-ornithophilous plants decreased the frequency of nectar robbing in H. spathocircinata flowers to a greater extent than ornithophilous ones. These results suggest that nectar robbing hummingbirds are attracted to similar conditions that attract legitimate visitors and that spatial aggregation and mixed-species displays may represent a mechanism to dilute nectar robbing effects at an individual level.
Collapse
Affiliation(s)
- Júlia Mendonça Almeida
- Graduação, Instituto de Biociências, Universidade Federal do Estado do Rio de Janeiro (UNIRIO), CEP, Avenida Pasteur, 458, Rio de Janeiro 22290-240, Brazil
| | - Caio César Corrêa Missagia
- Departamento de Ecologia, Programa de Pós-Graduação em Ecologia e Evolução, Instituto de Biologia Roberto Alcantara Gomes (IBRAG), Laboratório de Ecologia de Aves e Comportamento, Universidade do Estado do Rio de Janeiro (UERJ), Rua São Francisco Xavier, 524 Rio de Janeiro, RJ, CEP, Rio de Janeiro 20550-011, Brazil
| | - Maria Alice Santos Alves
- Departamento de Ecologia, IBRAG, Laboratório de Ecologia de Aves UERJ. Rua São Francisco Xavier, 524 Rio de Janeiro, RJ, CEP, Rio de Janeiro 20550-011, Brazil
| |
Collapse
|
7
|
Sargent AJ, Groom DJE, Rico-Guevara A. Locomotion and Energetics of Divergent Foraging Strategies in Hummingbirds: A Review. Integr Comp Biol 2021; 61:736-748. [PMID: 34113992 DOI: 10.1093/icb/icab124] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 06/02/2021] [Accepted: 06/08/2021] [Indexed: 11/13/2022] Open
Abstract
Hummingbirds have two main foraging strategies: territoriality (defending a patch of flowers) and traplining (foraging over routine circuits of isolated patches). Species are often classified as employing one or the other. Not only have these strategies been inconsistently defined within the behavioral literature, but this simple framework also neglects the substantial evidence for flexible foraging behavior displayed by hummingbirds. Despite these limitations, research on hummingbird foraging has explored the distinct avenues of selection that proponents of either strategy presumably face: trapliners maximizing foraging efficiency, and territorialists favoring speed and maneuverability for resource defense. In earlier studies, these functions were primarily examined through wing disc loading (ratio of body weight to the circular area swept out by the wings, WDL) and predicted hovering costs, with trapliners expected to exhibit lower WDL than territorialists and thus lower hovering costs. While these pioneering models continue to play a role in current research, early studies were constrained by modest technology, and the original expectations regarding WDL have not held up when applied across complex hummingbird assemblages. Current technological advances have allowed for innovative research on the biomechanics/energetics of hummingbird flight, such as allometric scaling relationships (e.g., wing area-flight performance) and the link between high burst lifting performance and territoriality. Providing a predictive framework based on these relationships will allow us to reexamine previous hypotheses, and explore the biomechanical trade-offs to different foraging strategies, which may yield divergent routes of selection for quintessential territoriality and traplining. With a biomechanical and morphofunctional lens, here we examine the locomotor and energetic facets that dictate hummingbird foraging, and provide (a) predictions regarding the behavioral, biomechanical, and morphofunctional associations with territoriality and traplining; and (b) proposed methods of testing them. By pursuing these knowledge gaps, future research could use a variety of traits to help clarify the operational definitions of territoriality and traplining, to better apply them in the field.
Collapse
Affiliation(s)
- A J Sargent
- Department of Biology, University of Washington, 24 Kincaid Hall, Seattle, WA 98105, USA.,Burke Museum of Natural History and Culture, 4300 15th Ave NE, Seattle, WA 98105, USA
| | - D J E Groom
- Department of Biology, University of Washington, 24 Kincaid Hall, Seattle, WA 98105, USA.,Burke Museum of Natural History and Culture, 4300 15th Ave NE, Seattle, WA 98105, USA.,Department of Biology, San Francisco State University, 1600 Holloway Avenue, San Francisco, CA 94132, USA
| | - A Rico-Guevara
- Department of Biology, University of Washington, 24 Kincaid Hall, Seattle, WA 98105, USA.,Burke Museum of Natural History and Culture, 4300 15th Ave NE, Seattle, WA 98105, USA
| |
Collapse
|
8
|
Rico-Guevara A, Rubega MA, Hurme KJ, Dudley R. Shifting Paradigms in the Mechanics of Nectar Extraction and Hummingbird Bill Morphology. Integr Org Biol 2019; 1:oby006. [PMID: 33791513 PMCID: PMC7671138 DOI: 10.1093/iob/oby006] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
As functional morphologists, we aim to connect structures, mechanisms, and emergent higher-scale phenomena (e.g., behavior), with the ulterior motive of addressing evolutionary patterns. The fit between flowers and hummingbird bills has long been used as an example of impressive co-evolution, and hence hummingbirds' foraging behavior and ecological associations have been the subject of intense study. To date, models of hummingbird foraging have been based on the almost two-centuries-old assumption that capillary rise loads nectar into hummingbird tongue grooves. Furthermore, the role of the bill in the drinking process has been overlooked, instead considering it as the mere vehicle with which to traverse the corolla and access the nectar chamber. As a scientific community, we have been making incorrect assumptions about the basic aspects of how hummingbirds extract nectar from flowers. In this article, we summarize recent advances on drinking biomechanics, morphological and ecological patterns, and selective forces involved in the shaping of the hummingbird feeding apparatus, and also address its modifications in a previously unexpected context, namely conspecific and heterospecific fighting. We explore questions such as: how do the mechanics of feeding define the limits and adaptive consequences of foraging behaviors? Which are the selective forces that drive bill and tongue shape, and associated sexually dimorphic traits? And finally, what are the proximate and ultimate causes of their foraging strategies, including exploitative and interference competition? Increasing our knowledge of morphology, mechanics, and diversity of hummingbird feeding structures will have implications for understanding the ecology and evolution of these remarkable animals.
Collapse
Affiliation(s)
- A Rico-Guevara
- Department of Integrative Biology, University of California, Berkeley, 3040 Valley Life Sciences Building, Berkeley, CA 94720, USA.,Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA.,Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Código Postal 11001, Bogotá DC, Colombia
| | - M A Rubega
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA
| | - K J Hurme
- Department of Integrative Biology, University of California, Berkeley, 3040 Valley Life Sciences Building, Berkeley, CA 94720, USA.,Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA
| | - R Dudley
- Department of Integrative Biology, University of California, Berkeley, 3040 Valley Life Sciences Building, Berkeley, CA 94720, USA
| |
Collapse
|
9
|
Temeles EJ, Rah YJ, Andicoechea J, Byanova KL, Giller GSJ, Stolk SB, Kress WJ. Pollinator-mediated selection in a specialized hummingbird-Heliconia system in the Eastern Caribbean. J Evol Biol 2012. [PMID: 23199234 DOI: 10.1111/jeb.12053] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phenotypic matches between plants and their pollinators often are interpreted as examples of reciprocal selection and adaptation. For the two co-occurring plant species, Heliconia bihai and H. caribaea in the Eastern Caribbean, we evaluated for five populations over 2 years the strength and direction of natural selection on corolla length and number of bracts per inflorescence. These plant traits correspond closely to the bill lengths and body masses of their primary pollinators, female or male purple-throated carib hummingbirds (Eulampis jugularis). In H. bihai, directional selection for longer corollas was always significant with the exception of one population in 1 year, whereas selection on bract numbers was rare and found only in one population in 1 year. In contrast, significant directional selection for more bracts per inflorescence occurred in all three populations of the yellow morph and in two populations of the red morph of H. caribaea, whereas significant directional selection on corolla length occurred in only one population of the red morph and one population of the yellow morph. Selection for longer corollas in H. bihai may result from better mechanical fit, and hence pollination, by the long bills of female E. jugularis, their sole pollinator. In contrast, competition between males of E. jugularis for territories may drive selection for more bracts in H. caribaea. Competitive exclusion of female E. jugularis by territorial males also implicates pollinator competition as a possible ecological mechanism for trait diversification in these plants.
Collapse
Affiliation(s)
- E J Temeles
- Department of Biology, Amherst College, Amherst, MA 01002, USA.
| | | | | | | | | | | | | |
Collapse
|