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Colwell RK, Rangel TF, Fučíková K, Sustaita D, Yanega GM, Rico-Guevara A. Repeated Evolution of Unorthodox Feeding Styles Drives a Negative Correlation between Foot Size and Bill Length in Hummingbirds. Am Nat 2023; 202:699-720. [PMID: 37963119 DOI: 10.1086/726036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2023]
Abstract
AbstractDifferences among hummingbird species in bill length and shape have rightly been viewed as adaptive in relation to the morphology of the flowers they visit for nectar. In this study we examine functional variation in a behaviorally related but neglected feature: hummingbird feet. We gathered records of hummingbirds clinging by their feet to feed legitimately as pollinators or illegitimately as nectar robbers-"unorthodox" feeding behaviors. We measured key features of bills and feet for 220 species of hummingbirds and compared the 66 known "clinger" species (covering virtually the entire scope of hummingbird body size) with the 144 presumed "non-clinger" species. Once the effects of phylogenetic signal, body size, and elevation above sea level are accounted for statistically, hummingbirds display a surprising but functionally interpretable negative correlation. Clingers with short bills and long hallux (hind-toe) claws have evolved-independently-more than 20 times and in every major clade. Their biomechanically enhanced feet allow them to save energy by clinging to feed legitimately on short-corolla flowers and by stealing nectar from long-corolla flowers. In contrast, long-billed species have shorter hallux claws, as plant species with long-corolla flowers enforce hovering to feed, simply by the way they present their flowers.
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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: 14] [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.
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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
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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.
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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
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Ocampo‐Sandoval M, Arizmendi‐Arriaga MDC, Olson ME, Sánchez‐González LA. Geographical variation in the bill–flower fit in a plant–pollinator interaction in western Mexico. Biotropica 2021. [DOI: 10.1111/btp.12962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Marisol Ocampo‐Sandoval
- Depto. de Biología Evolutiva Facultad de Ciencias Museo de Zoología “Alfonso L. Herrera” Universidad Nacional Autónoma de México Tlalnepantla México
| | | | - Mark E. Olson
- Instituto de Biología Universidad Nacional Autónoma de México Tlalnepantla México
| | - Luis A. Sánchez‐González
- Depto. de Biología Evolutiva Facultad de Ciencias Museo de Zoología “Alfonso L. Herrera” Universidad Nacional Autónoma de México Tlalnepantla México
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Hořák D, Janeček Š. A geographical perspective on the relationship between Impatiens spur lengths and bill lengths of sunbirds in Afrotropical mountains. Ecol Evol 2021; 11:3120-3129. [PMID: 33841772 PMCID: PMC8019056 DOI: 10.1002/ece3.7258] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 12/17/2020] [Accepted: 01/13/2021] [Indexed: 12/02/2022] Open
Abstract
Trait matching-a correlation between the morphology of plants and their pollinators-has been frequently observed in pollination interactions. Different intensities of natural selection in individual regions should cause such correlations to be observable across different local assemblages. In this study, we focused on matching between spur lengths of the genus Impatiens and bill lengths of sunbirds in tropical Africa. For 25 mountain and island locations, we compiled information about the composition and traits of local Impatiens and sunbird assemblages. We found that assemblage mean and maximum values of bill lengths were positively correlated with mean and maximum spur lengths across locations. Moreover, our results suggest that the positive correlations hold only for forest sunbird assemblages sharing the same habitat with Impatiens species. We further show that long-billed sunbirds seem to locally match the morphology of multiple Impatiens plant species, not vice versa. Our observation implies that trait matching significantly contributes to structuring of Impatiens-sunbird pollination systems. We suggest that special habitat preferences together with spatial isolation of mountain environment might play a role in this case.
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Affiliation(s)
- David Hořák
- Department of EcologyFaculty of ScienceCharles University in PraguePraha 2Czech Republic
| | - Štěpán Janeček
- Department of EcologyFaculty of ScienceCharles University in PraguePraha 2Czech Republic
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