ABSTRACT
Many animals make nests using materials they collect. In some cases, such as hamsters, nesting material is collected in the process of ordinary foraging for food; but storage in the sleeping chamber would turn it into nest material. However in other cases, such as birds, nesting materials cannot be eaten (and never were during evolution) but are collected using specific criteria, which presumably differ from the criteria used in foraging for food objects. Moreover, the collected sticks or objects are not just piled on top of each other but interwoven with specifically adapted behavioural patterns. Indeed, the collections can be specific to a particular phase in the building process. Further, in addition to collecting the appropriate object, the animal might shape it to provide an even better fit; for instance, the caddis fly cuts a leaf to suit the changing shape of its tube. Here the action patterns of the combined collection and integration behaviour have been augmented by shaping-cutting behaviour patterns. Many animals add further value to the collected items by gluing them together using a bodily excretion (such as spit, mucus, silk or faeces). Here specific wiping, tapping and pulling behaviour patterns have evolved to combine the collected items with the excretion, which is massaged into or spread over the collection with specific behaviour patterns. Finally, a few animals no longer collect objects for their nests but construct them entirely from excretions. Here the collection behaviour has been dropped but the ‘gluing together’ behaviour has been refined. Spiders are the most prominent examples of this evolutionary pinnacle of nest building ( Figure 1 ). <italic>A selection of orb weavers on a tree (emphatically not a phylogenetic tree) to demonstrate the various web types. On the ground we see distant ancestors and relatives (scorpion, mygalomorph, trapdoor spider and amaurobiid). Further ancestral relatives (eresid and agelenid) have built their webs on the base of the tree, a dictynid web spans the fork of the tree. The right-hand branch contains (in order from its base) the webs of the cribellates</italic> Stegodyphus <italic>followed by the orb-weaving hackled orb weaver</italic> Uloborus <italic>and the triangle spider</italic> Hypotiotes <italic>as well as the gladiator spider</italic> Deinopis <italic>and the line lasso spider</italic> Miagrammopes. <italic>The centre branch holds an ecribellate orb web which might be by the garden cross spider</italic> Araneus. <italic>The left-hand branch holds another ecribellate orb web, which might be by</italic> Meta <italic>or</italic> Tetragnatha; <italic>this branch also supports (on the extreme left) three-dimensional</italic> Theridiion <italic>(above) and</italic> Linyphia <italic>(below) type webs as well as (upper left to right) ecribellate orb webs by</italic> Theridiosoma <italic>and</italic> Scoloderus, <italic>and finally the bolas spider</italic> Mastophora <italic>with its glue-drop line web (from <xref ref-type="bibr" rid="ref18_76">Vollrath, 1988a</xref>). (For more details on web types, see <xref ref-type="bibr" rid="ref18_68">Stowe (1986)</xref> and <xref ref-type="bibr" rid="ref18_14">Eberhard (1990)</xref>, and for recent hypothesis on cladistic relationships of orb spiders, see</italic> <xref ref-type="bibr" rid="ref18_27"> <italic>Hormiga</italic> et al. (<italic>1995</italic>)</xref>.) https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781003210801/d008fc4e-848f-44f2-a981-3bf5a273442c/content/fig18_1.tif"/>
