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Radius construction by Micrathena duodecimspinosa (Araneae: Araneidae): a puzzle within a puzzle
- Eberhard, William
- TheJournal of arachnology 2019 v.47 no.1 pp. 57-62
- Araneidae, animal behavior, geometry, vibration, webs
- Araneid orb weavers systematically weaken the radii in their orbs by partially or completely removing the provisional radial lines laid during radius construction. Removal of provisional radii by Micrathena duodecimspinosa (O. Pickard-Cambridge, 1890) tended to be less complete for those radii that were attached later during the radius construction stage to the same frame line; this pattern differed from previous observations of provisional radius removal in two other araneids. Patterns of removal in M. duodecimspinosa were not in accord with a previous hypothesis that provisional radius removal functions to adjust radial tensions. In addition, M. duodecimspinosa moved in complex, jerky paths during radius construction that did not occur in previous or subsequent stages of construction. These movements resulted from the spider vibrating the entire web as she moved; their functional significance is unclear.