Why do some nectar foragers perch and others hover while probing flowers?

Dreisig, Hans

doi:10.1007/s10682-997-1510-5

Cited by 10 publications

(8 citation statements)

References 31 publications

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“…). One explanation for this phenomenon can be found in a study by Dreisig (), who compared foraging behaviors of the hovering hawkmoth and perching bumblebee. His model, which included the competition effect, concluded the following: (1) hovering only yields a higher rate of energy gain compared to perching when nectar volumes are high, due to the low competition for resources; and (2) hovering can only evolve as a pure evolutionary stable strategy if competition is reduced.…”

Section: Discussionmentioning

confidence: 99%

Sunbird hovering behavior is determined by both the forager and resource plant

Padyšáková

Janeček

2016

Biotropica

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The long-standing paradigm that pollination systems adapted to hovering birds evolved only in the New World was recently challenged by the discovery of hovering pollination by Old World specialized passerine pollinators. This raises the possibility that hovering pollination may evolve more easily than previously believed, given sufficient selective pressure on plant traits, on nectarivory, or both. We observed foraging behavior by the sunbird Cyanomitra oritis at flowers of the native Old World plant Impatiens sakeriana. We measured the length of pedicels and peduncles (PedPed length), which can make the flowers difficult to reach while the bird perches on the stem, and determined if it influenced sunbird hovering or perching at a flower. Detailed analyses of video recordings showed that sunbirds only hovered at flowers with a long PedPed, whereas they employed both foraging modes when an adequate perch was available. A hovering sunbird could deplete nectar in a shorter time than a perching one. The frequency of visits was not greater at flowers with longer PedPed or with more open I. sakeriana flowers in the vicinity. Our study provides evidence that sunbird behavior does not follow simple energetic models, and that some sunbird pollination systems in the Old World resemble highly specialized hummingbird systems in the New World much more than expected, especially the overall adaptation of the system to bird hovering.

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Section: Discussionmentioning

confidence: 99%

Sunbird hovering behavior is determined by both the forager and resource plant

Padyšáková

Janeček

2016

Biotropica

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“…Thus, large hawk moths feeding from five to 10 newly opened flowers could fly 100 m or more between flowers without needing to visit closer ones (Suzá n et al 1994) and an hour or more in search of mates or host plants (Ramaswamy 1988) before needing to feed or rest. This estimate is conservative, considering that hawk moths sit (instead of hover) while feeding from Datura and large cactus flowers Haber 1983;Silva and Sazima 1995), resulting in considerable energy conservation (Heinrich 1983;Dreisig 1997). Because of their small size, the energetic payoff would be even greater for Hyles lineata moths during the first few visits to Datura flowers when they presumably access the upper reaches of its nectaries.…”

Section: Floral Rewards and Attractantsmentioning

confidence: 99%

Trumpet Flowers of the Sonoran Desert: Floral Biology ofPeniocereusCacti and SacredDatura

Raguso

Henzel²,

Buchmann

et al. 2003

International Journal of Plant Sciences

114

126

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JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. The University of Chicago Press is collaborating with JSTOR to digitize, preserve and extend access to International Journal of Plant Sciences.The floral biology of night-blooming Peniocereus cacti and Datura plants was studied in North America's Sonoran Desert. In populations of two rare cactus species (Peniocereus greggii and Peniocereus striatus), individual plants bloom synchronously on less than five nights per year and are self-incompatible. In contrast, the abundant Datura discolor and Datura wrightii bloom nearly continuously from spring to autumn and are self-compatible. Flowers of all species studied are visited by hawk moths at dusk and by honeybees and native bees the following morning. Hawk moths have the appropriate behavior and body dimensions to pollinate Peniocereus effectively, but visits are rare. Nonnative honeybees also visit P. greggii and may contribute incrementally to fruit set. Peniocereus and Datura flowers are highly reflective at all wavelengths above 400 nm but lack UV reflectance or contrast. All species studied secrete 10-80 mL of sucrose-rich nectar within flared corollas so deep that moths must land within them, ensuring pollen carriage. These flowers provide rich energetic resources for hawk moths because the caloric content of a single flower would support from 3 to 20 min of hovering flight. Floral scents were more species specific than visual cues because D. discolor and D. wrightii emit complex blends of terpenoid, benzenoid, aliphatic, and nitrogenous scent compounds, whereas flowers of P. greggii produce only eight benzenoid compounds (all of which are present in Datura species) and Peniocereus striatus is scentless. Peniocereus cacti may benefit from sequential mutualism with the more abundant Datura species by way of pollinators nurtured as larvae by Datura foliage and as adults by Datura floral nectar.

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“…As 273 other nectarivorous birds need to perch while feeding, flowers without perches may represent a 274 relatively abundant and constant resource without competition from other bird species. Evolution 275 of hovering in this scenario may be a virtuous cycle as hovering is more efficient at high nectar 276 volumes which occur in the absence of competition (49). Secondly, hummingbirds may be better 277 able to escape predation due to their unique flying abilities.…”

Section: Results 175mentioning

confidence: 99%

Using Biogeography to Assess Key Adaptation Strength in Two Bird Families

Şekercioğlu

et al. 2017

Preprint

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27Adaptations can be thought of as evolutionary technologies that allow organisms to 28 exploit their environment. Like human technologies, adaptations can be 'progressive', increasing 29 in their ability to accomplish a task. Progressive adaptations which also fundamentally alter the 30 rules of trade-offs are known as key adaptations. Key adaptations allow a taxon to expand its 31 niche space thereby radiating to larger species numbers and spread beyond its original range. If 32 so, then of two otherwise ecologically equivalent taxa, the one with the greater geographical 33 range may have a key adaptation. We tested this hypothesis by comparing the global 34 biogeographic patterns of hummingbirds (Trochilidae) and sunbirds (Nectariniidae), ecologically 35 equivalent families with distinct evolutionary technologies. Though many species of both 36 families feed on nectar, hummingbirds also possess adaptations permitting hovering flight. We 37 analyzed each family's species diversity with latitude and elevation, charting how they decline 38 with movement towards poles and peaks. Hummingbirds persist into higher elevation and more 39 extreme latitudes than sunbirds, reaching their 50% species richness value at 22.14º and 2087 m 40 versus 18.92º and 2533 m for sunbirds. Looking at morphology, the evolution of hovering is 41 likely the constraint breaking adaptation that allowed hummingbirds to radiate into more species 42 and inhabit more extreme climes than sunbirds. Comparing the biogeography of ecologically-43 equivalent taxa has the potential to reveal insights into the species adaptations and niche 44 expansion.

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Why do some nectar foragers perch and others hover while probing flowers?

Cited by 10 publications

References 31 publications

Sunbird hovering behavior is determined by both the forager and resource plant

Sunbird hovering behavior is determined by both the forager and resource plant

Trumpet Flowers of the Sonoran Desert: Floral Biology ofPeniocereusCacti and SacredDatura

Using Biogeography to Assess Key Adaptation Strength in Two Bird Families

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