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Orb‐web Orientation and Modification by the Spiders Araneus diadematus and Araneus gemmoides (Araneae: Araneidae) in Response to Wind and Light
Author(s) -
Hieber Craig S.
Publication year - 1984
Publication title -
zeitschrift für tierpsychologie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.739
H-Index - 74
eISSN - 1439-0310
pISSN - 0044-3573
DOI - 10.1111/j.1439-0310.1984.tb00103.x
Subject(s) - orb (optics) , spider , araneus , biology , ecology , computer science , artificial intelligence , image (mathematics)
and Summary Most orb‐weaving spiders (Araneidae) possess the behavioral capacity to orient and modify their planar webs in response to wind and direct sunlight. These behaviors have generally been interpreted as tactics to avoid thermal loading of the spider or damage to the web. However, previous studies have focused primarily on diurnal araneids that sit at the hubs of their webs in exposed habitats. Here the orientations and modifications of the webs to wind and light for Araneus diadematus and Araneus gemmoides , two spiders which use retreats in less exposed habitats, are examined. Light had no effect on the web structure of A. diadematus or on its web orientation. Araneus gemmoides , however, demonstrated a significant perpendicular orientation of the plane of the web to light; a response which is probably to increase prey interception rather than control isolation. In response to wind, A. diadematus demonstrated a significant reduction in the surface area of the web, while A. gemmoides demonstrated a significant parallel orientation of the web to wind with no change in web structure. The responses of both spiders to wind resemble behaviors shown by other orb‐weavers, and probably function to avoid web damage. These responses to wind and light are related to the use of a retreat, and to differences in web building behavior and habitat. Zusammenfassung1 Die Orientierung und der Bau der Fangnetze zweier Araneus‐Arten unter Wind‐ und Lichteinfluß wurden im Windkanal untersucht. 2 Licht hatte auf Struktur und Orientierung der Netze von A. diadematus keinen Effekt. A. gemmoides zeigte jedoch im Licht eine deutliche Vertikal‐Orientierung der Netzebene. Diese Spinne scheint ihr Netz nach dem Licht auszurichten; vielleicht steigert das die Beutemenge. 3 Als Reaktion auf Wind nahm bei A. diadematus die Netzfläche deutlich ab. A. gemmoides hingegen orientierte das Netz parallel zum Wind, verkleinerte es aber nicht. Beide Reaktionen ähneln dem Verhalten anderer Radnetzspinnen und dienen wahrscheinlich dazu, Netzschäden zu vermeiden.