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York Winter - One of the best experts on this subject based on the ideXlab platform.
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Interval timing behavior in Pallas's long-tongued bat (Glossophaga soricina).
Journal of comparative psychology (Washington D.C. : 1983), 2013Co-Authors: Ulf Toelch, York WinterAbstract:Timing behavior in animals and its underlying mechanisms have been investigated extensively in the peak procedure, a variant of fixed interval procedures. In such experiments, individuals typically start responding with high frequency after an initial inactive time interval and continue their responses after peak time if rewards are omitted. This begs the so far unexplored question as to how timing behavior is influenced when such continuous responses are suppressed. Here, we present results from a nectar-feeding bat species, Glossophaga soricina, that was tested in a modified version of the peak procedure at three fixed time intervals (5 s, 11 s, 20 s). In contrast to standard peak procedures we imposed metabolic costs on individual responses which effectively suppressed trains of rapid responses during trials. Under this manipulation, bats' aggregated responses showed clear peaks around the peak time in the 5-s and 11-s schedules. Bats' responses in the 20-s schedule, however, did not peak around the fixed interval time. Crucially, an analysis of time intervals between successive revisits in all schedules revealed that bats revisited feeders at accurately timed intervals in all three conditions. The individual within trial behavioral responses showed clear oscillatory patterns throughout nonrewarded trials. These findings follow predictions from mechanistic timing models, like the striatal beat frequency model, and are discussed with regard to these models.
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The near and far wake of Pallas' long tongued bat (Glossophaga soricina).
Journal of Experimental Biology, 2008Co-Authors: L. Christoffer Johansson, York Winter, Marta Wolf, Rhea Von Busse, Geoffrey Spedding, Anders HedenströmAbstract:The wake structures of a bat in flight have a number of characteristics not associated with any of the bird species studied to this point. Unique features include discrete vortex rings generating negative lift at the end of the upstroke at medium and high speeds, each wing generating its own vortex loop, and a systematic variation in the circulation of the start and stop vortices along the wingspan, with increasing strength towards the wing tips. Here we analyse in further detail some previously published data from quantitative measurements of the wake behind a small bat species flying at speeds ranging from 1.5 to 7 m s(-1) in a wind tunnel. The data are extended to include both near- and far-wake measurements. The near-/far-wake comparisons show that although the measured peak vorticity of the start and stop vortices decreases with increasing downstream distance from the wing, the total circulation remains approximately constant. As the wake evolves, the diffuse stop vortex shed at the inner wing forms a more concentrated vortex in the far wake. Taken together, the results show that studying the far wake, which has been the standard procedure, nevertheless risks missing details of the wake. Although study of the far wake alone can lead to the misinterpretation of the wake topology, the net, overall circulation of the main wake vortices can be preserved so that approximate momentum balance calculations are not unreasonable within the inevitably large experimental uncertainties.
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Effect of local spatial cues in small-scale orientation of flower bats
Animal Behaviour, 2008Co-Authors: Ulf Toelch, Kai Petra Stich, Clifton Lee Gass, York WinterAbstract:It is crucial for nectar-feeding animals to re-locate profitable flowers. However, neither flower shape nor colour signal the nectar content of a single flower. Such information can emerge only by an animal remembering experienced foraging profitability. Furthermore, this requires the ability to spatially discriminate between individual flowers of similar appearance, which appears to be demanding especially when multiple flowers of the same species are aggregated. In a study of the foraging behaviour of nectar-feeding bats, Glossophaga soricina, we investigated the effect of local echo acoustic cues that were spatially separated by at least 40 cm from the goal in a multiple goal-finding task. Increasing density of local spatial cues improved accuracy in re-locating rewarding feeders by helping bats identify profitable flowers on a small scale.
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Psychometric function for nectar volume perception of a flower-visiting bat A Neuroethology, sensory, neural, and behavioral physiology
Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology, 2007Co-Authors: Ulf Toelch, York WinterAbstract:For foraging pollinators one aspect of floral quality is the volume of nectar available. Thus, nectar-feeding animals should be able to estimate volumes of received nectar. In this study, we determined the psychometric function for nectar volume discrimination of a Neotropical flower-visiting bat Glossophaga soricina. For this, we examined the ability of bats to discriminate between two nectar volumes in a two-alternative forced-choice paradigm. We used a Bayesian inference approach to determine psychometric functions. From the derived psychometric function we assessed the discrimination threshold at a value of 0.69. G. soricina could clearly distinguish between two volumes, when the difference between the two nectar volumes divided by their average exceeded this value. This indicates that bats possess a sense for the perception and discrimination of volumes of nectar that is better developed than in honeybees.
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Psychometric function for nectar volume perception of a flower-visiting bat
Journal of comparative physiology. A Neuroethology sensory neural and behavioral physiology, 2006Co-Authors: Ulf Toelch, York WinterAbstract:For foraging pollinators one aspect of floral quality is the volume of nectar available. Thus, nectar-feeding animals should be able to estimate volumes of received nectar. In this study, we determined the psychometric function for nectar volume discrimination of a Neotropical flower-visiting bat Glossophaga soricina. For this, we examined the ability of bats to discriminate between two nectar volumes in a two-alternative forced-choice paradigm. We used a Bayesian inference approach to determine psychometric functions. From the derived psychometric function we assessed the discrimination threshold at a value of 0.69. G. soricina could clearly distinguish between two volumes, when the difference between the two nectar volumes divided by their average exceeded this value. This indicates that bats possess a sense for the perception and discrimination of volumes of nectar that is better developed than in honeybees.
Fabrício R. Santos - One of the best experts on this subject based on the ideXlab platform.
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Biogeographic scenarios for the diversification of a widespread Neotropical species, Glossophaga soricina (Chiroptera: Phyllostomidae)
Systematics and Biodiversity, 2017Co-Authors: Cayo Augusto Rocha Dias, José Eustáquio Dos Santos Júnior, Fernando A. Perini, Fabrício R. SantosAbstract:In order to contribute to the understanding of the effect of geological and climatic changes on species diversification in the Neotropics, we employed molecular techniques to study the population dynamics of the glossophagine bat Glossophaga soricina, a widespread species in the Neotropical region. We aimed to assess the dispersal and distribution of mtDNA lineages of G. soricina and evaluate the possible effect of vicariant events in the population history and dynamics. Glossophaga soricina presented two main highly supported mtDNA lineages, which diverged between ∼2.4 and 5 million years ago, probably following a vicariant event caused by the Andes final uplift. The lower sea level during Pleistocene glaciations also made possible the occupation of Jamaica after an event of dispersion over the Caribbean Sea, although past climatic fluctuations had little effect over population dynamics of G. soricina. Our results corroborate the idea that the Andes uplift played an important role in the evolution of Neo...
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Biogeographic scenarios for the diversification of a widespread Neotropical species, Glossophaga soricina (Chiroptera: Phyllostomidae)
2017Co-Authors: Cayo Rocha A. Dias, Fernando A. Perini, José Santos E. Júnior, Fabrício R. SantosAbstract:In order to contribute to the understanding of the effect of geological and climatic changes on species diversification in the Neotropics, we employed molecular techniques to study the population dynamics of the glossophagine bat Glossophaga soricina, a widespread species in the Neotropical region. We aimed to assess the dispersal and distribution of mtDNA lineages of G. soricina and evaluate the possible effect of vicariant events in the population history and dynamics. Glossophaga soricina presented two main highly supported mtDNA lineages, which diverged between ∼2.4 and 5 million years ago, probably following a vicariant event caused by the Andes final uplift. The lower sea level during Pleistocene glaciations also made possible the occupation of Jamaica after an event of dispersion over the Caribbean Sea, although past climatic fluctuations had little effect over population dynamics of G. soricina. Our results corroborate the idea that the Andes uplift played an important role in the evolution of Neotropical biodiversity. In this context we suggest that geographic events causing large scale environmental disjunction, such as the uplift of mountains, are more likely to restrict gene flow amongst populations of tolerant species with broad geographic range than local climate driven environmental changes.
Ulf Toelch - One of the best experts on this subject based on the ideXlab platform.
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Interval timing behavior in Pallas's long-tongued bat (Glossophaga soricina).
Journal of comparative psychology (Washington D.C. : 1983), 2013Co-Authors: Ulf Toelch, York WinterAbstract:Timing behavior in animals and its underlying mechanisms have been investigated extensively in the peak procedure, a variant of fixed interval procedures. In such experiments, individuals typically start responding with high frequency after an initial inactive time interval and continue their responses after peak time if rewards are omitted. This begs the so far unexplored question as to how timing behavior is influenced when such continuous responses are suppressed. Here, we present results from a nectar-feeding bat species, Glossophaga soricina, that was tested in a modified version of the peak procedure at three fixed time intervals (5 s, 11 s, 20 s). In contrast to standard peak procedures we imposed metabolic costs on individual responses which effectively suppressed trains of rapid responses during trials. Under this manipulation, bats' aggregated responses showed clear peaks around the peak time in the 5-s and 11-s schedules. Bats' responses in the 20-s schedule, however, did not peak around the fixed interval time. Crucially, an analysis of time intervals between successive revisits in all schedules revealed that bats revisited feeders at accurately timed intervals in all three conditions. The individual within trial behavioral responses showed clear oscillatory patterns throughout nonrewarded trials. These findings follow predictions from mechanistic timing models, like the striatal beat frequency model, and are discussed with regard to these models.
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Effect of local spatial cues in small-scale orientation of flower bats
Animal Behaviour, 2008Co-Authors: Ulf Toelch, Kai Petra Stich, Clifton Lee Gass, York WinterAbstract:It is crucial for nectar-feeding animals to re-locate profitable flowers. However, neither flower shape nor colour signal the nectar content of a single flower. Such information can emerge only by an animal remembering experienced foraging profitability. Furthermore, this requires the ability to spatially discriminate between individual flowers of similar appearance, which appears to be demanding especially when multiple flowers of the same species are aggregated. In a study of the foraging behaviour of nectar-feeding bats, Glossophaga soricina, we investigated the effect of local echo acoustic cues that were spatially separated by at least 40 cm from the goal in a multiple goal-finding task. Increasing density of local spatial cues improved accuracy in re-locating rewarding feeders by helping bats identify profitable flowers on a small scale.
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Psychometric function for nectar volume perception of a flower-visiting bat A Neuroethology, sensory, neural, and behavioral physiology
Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology, 2007Co-Authors: Ulf Toelch, York WinterAbstract:For foraging pollinators one aspect of floral quality is the volume of nectar available. Thus, nectar-feeding animals should be able to estimate volumes of received nectar. In this study, we determined the psychometric function for nectar volume discrimination of a Neotropical flower-visiting bat Glossophaga soricina. For this, we examined the ability of bats to discriminate between two nectar volumes in a two-alternative forced-choice paradigm. We used a Bayesian inference approach to determine psychometric functions. From the derived psychometric function we assessed the discrimination threshold at a value of 0.69. G. soricina could clearly distinguish between two volumes, when the difference between the two nectar volumes divided by their average exceeded this value. This indicates that bats possess a sense for the perception and discrimination of volumes of nectar that is better developed than in honeybees.
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Psychometric function for nectar volume perception of a flower-visiting bat
Journal of comparative physiology. A Neuroethology sensory neural and behavioral physiology, 2006Co-Authors: Ulf Toelch, York WinterAbstract:For foraging pollinators one aspect of floral quality is the volume of nectar available. Thus, nectar-feeding animals should be able to estimate volumes of received nectar. In this study, we determined the psychometric function for nectar volume discrimination of a Neotropical flower-visiting bat Glossophaga soricina. For this, we examined the ability of bats to discriminate between two nectar volumes in a two-alternative forced-choice paradigm. We used a Bayesian inference approach to determine psychometric functions. From the derived psychometric function we assessed the discrimination threshold at a value of 0.69. G. soricina could clearly distinguish between two volumes, when the difference between the two nectar volumes divided by their average exceeded this value. This indicates that bats possess a sense for the perception and discrimination of volumes of nectar that is better developed than in honeybees.
O. Von Helversen - One of the best experts on this subject based on the ideXlab platform.
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Sulphur-containing "perfumes" attract flower-visiting bats.
Journal of comparative physiology. A Sensory neural and behavioral physiology, 2000Co-Authors: O. Von Helversen, L. Winkler, Hans‐jürgen BestmannAbstract:We tested the attractiveness of individual scent compounds of bat-pollinated flowers to their pollinators, small flower-visiting bats of the genus Glossophaga (Phyllostomidae). Twenty compounds belonging to four different chemical substance classes were tested, both in the laboratory and in the field. In the laboratory, the bats (Glossophaga soricina) approached odour sources spontaneously and without preceding experience. Without ever receiving any reward they preferred the scent of a sulphur-containing compound, dimethyl disulphide, to several other odour components emitted by bat-pollinated flowers, and to scentless controls. In the field, at La Selva station in the tropical lowland rain forest of Costa Rica, G. commissarisi were attracted by two sulphur-containing compounds, dimethyl disulphide and 2,4-dithiapentane, to visit artificial flowers filled with sugar water. Thus, in nectarivorous bats the sense of smell obviously plays an important role in searching for and localising food sources, and even single components of the scent bouquets of bat-pollinated flowers are attractive. The preference for sulphur-containing odours seems to be innate.
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Bat Pollination of Weberocereus tunilla, an Epiphytic Rain Forest Cactus with Functional Flagelliflory
Plant Biology, 1999Co-Authors: Marco Tschapka, O. Von Helversen, Wilhelm BarthlottAbstract:: We studied the pollination of the epiphytic cactus Weberocereus tunilla (Weber) Britton and Rose at the La Selva Biological Station in the Atlantic lowland rain forest of Costa Rica. The large, night-blooming, unpleasantly-smelling flowers were suspended on elongated main stems that hang down as much as 2 m below canopy tree branches, resulting in a unique form of flagelliflory. The only visitors to flowers were three species of glossophagine bats: Glossophaga commissarisi, Hylonycteris underwoodi and Lichonycteris obscura. Patterns of nectar secretion and concentration were found to be typical for bat-pollinated flowers. Flowering phenology and the occurrence of pollen on bats were recorded during a 1-yr period. Preliminary observations suggest that at least two other Costa Rican species of Weberocereus, W. biolleyi and W. trichophorus and possibly other species of the tribe Hylocereeae, are also pollinated by glossophagine bats.
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Gas exchange during hovering flight in a nectar-feeding bat Glossophaga soricina.
The Journal of Experimental Biology, 1998Co-Authors: Y. Winter, Christian C. Voigt, O. Von HelversenAbstract:Glossophagine nectar-feeding bats exploit flowers while hovering in front of them. Aerodynamic theory predicts that power output for hovering flight in Glossophaga soricina is 2.6 times higher than during horizontal flight. We tested this prediction by measuring rates of gas exchange during hover-feeding. Five individuals of Glossophaga soricina (mean mass 11.7 g) were trained to feed from a nectar dispenser designed as a flow-through respirometry mask. Single hover-feeding events lasted for up to 4.5 s. Measured rates of gas exchange varied as a function of hovering duration. O2 and CO2 during short hovering events (up to 1 s) were 20.5+/-6.7 ml g-1 h-1 (N=55) and 21.6+/-5.6 ml g-1 h-1 (N=39) (means +/- S.D.), respectively. These values are in the range of a previous estimate of the metabolic power input for level forward flight (23.8 ml O2 g-1 h-1). However, during hovering events lasting longer than 3 s, oxygen uptake was only 16.7+/-3.5 ml g-1 h-1 (N=73), which is only 70 % of the value expected for forward flight. Thus, bats reduced their rate of oxygen uptake during longer periods of hovering compared with level forward flight. This result is in contrast to the predicted hovering cost derived from aerodynamic theory. The exact metabolic power input during hovering remains uncertain. During longer hovering events, bats were probably not in respiratory steady state, as indicated by the deviation of the respiratory exchange ratio from the expected value of 1 (oxidization of nectar sugar) to the measured value of 0.8.
Cayo Augusto Rocha Dias - One of the best experts on this subject based on the ideXlab platform.
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Biogeographic scenarios for the diversification of a widespread Neotropical species, Glossophaga soricina (Chiroptera: Phyllostomidae)
Systematics and Biodiversity, 2017Co-Authors: Cayo Augusto Rocha Dias, José Eustáquio Dos Santos Júnior, Fernando A. Perini, Fabrício R. SantosAbstract:In order to contribute to the understanding of the effect of geological and climatic changes on species diversification in the Neotropics, we employed molecular techniques to study the population dynamics of the glossophagine bat Glossophaga soricina, a widespread species in the Neotropical region. We aimed to assess the dispersal and distribution of mtDNA lineages of G. soricina and evaluate the possible effect of vicariant events in the population history and dynamics. Glossophaga soricina presented two main highly supported mtDNA lineages, which diverged between ∼2.4 and 5 million years ago, probably following a vicariant event caused by the Andes final uplift. The lower sea level during Pleistocene glaciations also made possible the occupation of Jamaica after an event of dispersion over the Caribbean Sea, although past climatic fluctuations had little effect over population dynamics of G. soricina. Our results corroborate the idea that the Andes uplift played an important role in the evolution of Neo...