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Arenicola

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Rudiger Wehner – 1st expert on this subject based on the ideXlab platform

  • Vision in the nocturnal wandering spider Leucorchestris Arenicola (Araneae: Sparassidae).
    The Journal of experimental biology, 2020
    Co-Authors: Thomas Norgaard, Daneric Nilsson, Joh R Henschel, Anders Garm, Rudiger Wehner

    Abstract:

    At night the Namib Desert spider Leucorchestris Arenicola performs long-distance homing across its sand dune habitat. By disabling all or pairs of the spiders’ eight eyes we found that homing ability was severely reduced when vision was fully abolished. Vision, therefore, seems to play a key role in the nocturnal navigational performances of L. Arenicola. After excluding two or three pairs of eyes, the spiders were found to be able to navigate successfully using only their lateral eyes or only their anterior median eyes. Measurement of the eyes’ visual fields showed that the secondary eyes combined have a near full (panoramic) view of the surroundings. The visual fields of the principal eyes overlap almost completely with those of the anterior lateral eyes. Electroretinogram recordings indicate that each eye type contains a single photopigment with sensitivity peaking at approximately 525 nm in the posterior and anteriomedian eyes, and at approximately 540 nm in the anteriolateral eyes. Theoretical calculations of photon catches showed that the eyes are likely to employ a combination of spatial and temporal pooling in order to function at night. Under starlit conditions, the raw spatial and temporal resolution of the eyes is insufficient for detecting any visual information on structures in the landscape, and bright stars would be the only objects visible to the spiders. However, by summation in space and time, the spiders can rescue enough vision to detect coarse landscape structures. We show that L. Arenicola spiders are likely to be using temporal summation to navigate at night.

  • vision in the nocturnal wandering spider leucorchestris Arenicola araneae sparassidae
    The Journal of Experimental Biology, 2008
    Co-Authors: Thomas Norgaard, Daneric Nilsson, Joh R Henschel, Anders Garm, Rudiger Wehner

    Abstract:

    At night the Namib Desert spider Leucorchestris Arenicola performs long-distance homing across its sand dune habitat. By disabling all or pairs of the spiders’ eight eyes we found that homing ability was severely reduced when vision was fully abolished. Vision, therefore, seems to play a key role in the nocturnal navigational performances of L. Arenicola . After excluding two or three pairs of eyes, the spiders were found to be able to navigate successfully using only their lateral eyes or only their anterior median eyes. Measurement of the eyes’ visual fields showed that the secondary eyes combined have a near full (panoramic) view of the surroundings. The visual fields of the principal eyes overlap almost completely with those of the anterior lateral eyes. Electroretinogram recordings indicate that each eye type contains a single photopigment with sensitivity peaking at ∼525 nm in the posterior and anteriomedian eyes, and at ∼540 nm in the anteriolateral eyes. Theoretical calculations of photon catches showed that the eyes are likely to employ a combination of spatial and temporal pooling in order to function at night. Under starlit conditions, the raw spatial and temporal resolution of the eyes is insufficient for detecting any visual information on structures in the landscape, and bright stars would be the only objects visible to the spiders. However, by summation in space and time, the spiders can rescue enough vision to detect coarse landscape structures. We show that L. Arenicola spiders are likely to be using temporal summation to navigate at night.

  • Use of local cues in the night-time navigation of the wandering desert spider Leucorchestris Arenicola (Araneae, Sparassidae)
    Journal of Comparative Physiology A, 2007
    Co-Authors: Thomas Norgaard, Joh R Henschel, Rudiger Wehner

    Abstract:

    Adult male Leucorchestris Arenicola can walk round-trips of several tens of meters in search of females. Most excursions end with the spiders returning to their burrow. For small animals homing over distances of several meters is theoretically impossible without the aid of external cues. It was investigated, whether the spiders use local cues or they rely solely on global cues. Individually marked male spiders were captured during their excursions and displaced several meters inside an opaque box. Ten out of twelve displaced spiders returned to their burrows. This shows that the male L. Arenicola are using local cues during their homing, as the comparatively small displacement distances could not be detected by means of global, e.g. celestial cues. In order to test whether the spiders could be using olfactory guidance, the burrows were displaced by 2 m while the spiders were out on their journeys. In 12 out of 15 experiments, the spiders did not find their burrows. These results show that the burrows do not function as olfactory beacons for the homing spiders.

Thomas Norgaard – 2nd expert on this subject based on the ideXlab platform

  • Vision in the nocturnal wandering spider Leucorchestris Arenicola (Araneae: Sparassidae).
    The Journal of experimental biology, 2020
    Co-Authors: Thomas Norgaard, Daneric Nilsson, Joh R Henschel, Anders Garm, Rudiger Wehner

    Abstract:

    At night the Namib Desert spider Leucorchestris Arenicola performs long-distance homing across its sand dune habitat. By disabling all or pairs of the spiders’ eight eyes we found that homing ability was severely reduced when vision was fully abolished. Vision, therefore, seems to play a key role in the nocturnal navigational performances of L. Arenicola. After excluding two or three pairs of eyes, the spiders were found to be able to navigate successfully using only their lateral eyes or only their anterior median eyes. Measurement of the eyes’ visual fields showed that the secondary eyes combined have a near full (panoramic) view of the surroundings. The visual fields of the principal eyes overlap almost completely with those of the anterior lateral eyes. Electroretinogram recordings indicate that each eye type contains a single photopigment with sensitivity peaking at approximately 525 nm in the posterior and anteriomedian eyes, and at approximately 540 nm in the anteriolateral eyes. Theoretical calculations of photon catches showed that the eyes are likely to employ a combination of spatial and temporal pooling in order to function at night. Under starlit conditions, the raw spatial and temporal resolution of the eyes is insufficient for detecting any visual information on structures in the landscape, and bright stars would be the only objects visible to the spiders. However, by summation in space and time, the spiders can rescue enough vision to detect coarse landscape structures. We show that L. Arenicola spiders are likely to be using temporal summation to navigate at night.

  • vision in the nocturnal wandering spider leucorchestris Arenicola araneae sparassidae
    The Journal of Experimental Biology, 2008
    Co-Authors: Thomas Norgaard, Daneric Nilsson, Joh R Henschel, Anders Garm, Rudiger Wehner

    Abstract:

    At night the Namib Desert spider Leucorchestris Arenicola performs long-distance homing across its sand dune habitat. By disabling all or pairs of the spiders’ eight eyes we found that homing ability was severely reduced when vision was fully abolished. Vision, therefore, seems to play a key role in the nocturnal navigational performances of L. Arenicola . After excluding two or three pairs of eyes, the spiders were found to be able to navigate successfully using only their lateral eyes or only their anterior median eyes. Measurement of the eyes’ visual fields showed that the secondary eyes combined have a near full (panoramic) view of the surroundings. The visual fields of the principal eyes overlap almost completely with those of the anterior lateral eyes. Electroretinogram recordings indicate that each eye type contains a single photopigment with sensitivity peaking at ∼525 nm in the posterior and anteriomedian eyes, and at ∼540 nm in the anteriolateral eyes. Theoretical calculations of photon catches showed that the eyes are likely to employ a combination of spatial and temporal pooling in order to function at night. Under starlit conditions, the raw spatial and temporal resolution of the eyes is insufficient for detecting any visual information on structures in the landscape, and bright stars would be the only objects visible to the spiders. However, by summation in space and time, the spiders can rescue enough vision to detect coarse landscape structures. We show that L. Arenicola spiders are likely to be using temporal summation to navigate at night.

  • Use of local cues in the night-time navigation of the wandering desert spider Leucorchestris Arenicola (Araneae, Sparassidae)
    Journal of Comparative Physiology A, 2007
    Co-Authors: Thomas Norgaard, Joh R Henschel, Rudiger Wehner

    Abstract:

    Adult male Leucorchestris Arenicola can walk round-trips of several tens of meters in search of females. Most excursions end with the spiders returning to their burrow. For small animals homing over distances of several meters is theoretically impossible without the aid of external cues. It was investigated, whether the spiders use local cues or they rely solely on global cues. Individually marked male spiders were captured during their excursions and displaced several meters inside an opaque box. Ten out of twelve displaced spiders returned to their burrows. This shows that the male L. Arenicola are using local cues during their homing, as the comparatively small displacement distances could not be detected by means of global, e.g. celestial cues. In order to test whether the spiders could be using olfactory guidance, the burrows were displaced by 2 m while the spiders were out on their journeys. In 12 out of 15 experiments, the spiders did not find their burrows. These results show that the burrows do not function as olfactory beacons for the homing spiders.

Joh R Henschel – 3rd expert on this subject based on the ideXlab platform

  • Vision in the nocturnal wandering spider Leucorchestris Arenicola (Araneae: Sparassidae).
    The Journal of experimental biology, 2020
    Co-Authors: Thomas Norgaard, Daneric Nilsson, Joh R Henschel, Anders Garm, Rudiger Wehner

    Abstract:

    At night the Namib Desert spider Leucorchestris Arenicola performs long-distance homing across its sand dune habitat. By disabling all or pairs of the spiders’ eight eyes we found that homing ability was severely reduced when vision was fully abolished. Vision, therefore, seems to play a key role in the nocturnal navigational performances of L. Arenicola. After excluding two or three pairs of eyes, the spiders were found to be able to navigate successfully using only their lateral eyes or only their anterior median eyes. Measurement of the eyes’ visual fields showed that the secondary eyes combined have a near full (panoramic) view of the surroundings. The visual fields of the principal eyes overlap almost completely with those of the anterior lateral eyes. Electroretinogram recordings indicate that each eye type contains a single photopigment with sensitivity peaking at approximately 525 nm in the posterior and anteriomedian eyes, and at approximately 540 nm in the anteriolateral eyes. Theoretical calculations of photon catches showed that the eyes are likely to employ a combination of spatial and temporal pooling in order to function at night. Under starlit conditions, the raw spatial and temporal resolution of the eyes is insufficient for detecting any visual information on structures in the landscape, and bright stars would be the only objects visible to the spiders. However, by summation in space and time, the spiders can rescue enough vision to detect coarse landscape structures. We show that L. Arenicola spiders are likely to be using temporal summation to navigate at night.

  • vision in the nocturnal wandering spider leucorchestris Arenicola araneae sparassidae
    The Journal of Experimental Biology, 2008
    Co-Authors: Thomas Norgaard, Daneric Nilsson, Joh R Henschel, Anders Garm, Rudiger Wehner

    Abstract:

    At night the Namib Desert spider Leucorchestris Arenicola performs long-distance homing across its sand dune habitat. By disabling all or pairs of the spiders’ eight eyes we found that homing ability was severely reduced when vision was fully abolished. Vision, therefore, seems to play a key role in the nocturnal navigational performances of L. Arenicola . After excluding two or three pairs of eyes, the spiders were found to be able to navigate successfully using only their lateral eyes or only their anterior median eyes. Measurement of the eyes’ visual fields showed that the secondary eyes combined have a near full (panoramic) view of the surroundings. The visual fields of the principal eyes overlap almost completely with those of the anterior lateral eyes. Electroretinogram recordings indicate that each eye type contains a single photopigment with sensitivity peaking at ∼525 nm in the posterior and anteriomedian eyes, and at ∼540 nm in the anteriolateral eyes. Theoretical calculations of photon catches showed that the eyes are likely to employ a combination of spatial and temporal pooling in order to function at night. Under starlit conditions, the raw spatial and temporal resolution of the eyes is insufficient for detecting any visual information on structures in the landscape, and bright stars would be the only objects visible to the spiders. However, by summation in space and time, the spiders can rescue enough vision to detect coarse landscape structures. We show that L. Arenicola spiders are likely to be using temporal summation to navigate at night.

  • Use of local cues in the night-time navigation of the wandering desert spider Leucorchestris Arenicola (Araneae, Sparassidae)
    Journal of Comparative Physiology A, 2007
    Co-Authors: Thomas Norgaard, Joh R Henschel, Rudiger Wehner

    Abstract:

    Adult male Leucorchestris Arenicola can walk round-trips of several tens of meters in search of females. Most excursions end with the spiders returning to their burrow. For small animals homing over distances of several meters is theoretically impossible without the aid of external cues. It was investigated, whether the spiders use local cues or they rely solely on global cues. Individually marked male spiders were captured during their excursions and displaced several meters inside an opaque box. Ten out of twelve displaced spiders returned to their burrows. This shows that the male L. Arenicola are using local cues during their homing, as the comparatively small displacement distances could not be detected by means of global, e.g. celestial cues. In order to test whether the spiders could be using olfactory guidance, the burrows were displaced by 2 m while the spiders were out on their journeys. In 12 out of 15 experiments, the spiders did not find their burrows. These results show that the burrows do not function as olfactory beacons for the homing spiders.