Chapter 1. Introduction 1.1 Introduction 1.2 A foreign world: life tied to silk lines 1.3 A brief history of spider web studies 1.4 Emphasis on behavior 1.5 The scope of this book and tactics in presentation 1.6 Evolutionary history and phylogeny 1.
7 Terminology and other procedural matters 1.8 Acknowledgments Chapter 2. The "hardware" of web-building spiders: morphology, silk, and behavior 2.1. Introduction 2.2 Silk glands and silk 2.2.1 Origins 2.
2.2 Mechanical properties and how they are determined 2.2.3 Major ampullate glands 2.2.4 Minor ampullate glands 2.2.5 Aciniform glands 2.
2.6 Flagelliform glands 2.2.7 Pseudoflagelliform glands 2.2.8 Sticky silk 2.2.8.
1 Cribellum glands 2.2.8.2 Aggregate glands 2.2.8.3 Venom glands that produce contractile sticky "webs" in Scytodidae 2.2.
8.4 Ampullate glands in Loxosceles 2.2.9 Piriform glands 2.2.9.1 Spinneret morphology 2.2.
9.2 Morphology of attachment discs 2.2.9.3 Different attachment disc morphologies result from spinneret behavior and morphology 2.2.9.4 The "piriform queen"-- Cyrtophora citricola 2.
2.10 Epiandrous glands 2.2.11 Other products associated with silk 2.2.12 Control of rates of silk secretion in glands 2.2.13 Forming bridge lines 2.
3 Spinnerets as high-precision instruments 2.3.1 Ancestral morphology and behavior 2.3.2 Strategic placements of spigots on the spinnerets of araneomorphs 2.3.2.1 General considerations 2.
3.2.2 Special cases involving web designs 2.3.2.3 Additional complications 2.3.3 Phylogenetic inertia? 2.
3.4 Behavior of the spinnerets 2.3.5 How are lines terminated? 2.4 Leg morphology and behavior: grasping lines precisely and securely 2.4.1 Grasping lines in a web; tarsal morphology and leg movements 2.4.
2 Complementary searching and grasping behavior 2.4.2.1 The blind man''s cane and the art of following 2.4.2.2 Asymmetric searching movements that match asymmetric tarsal morphology 2.4.
2.3 An additional detail: rotating legs to grasp lines 2.4.3 Grasping a line prior to attaching the dragline 2.5 Cutting lines and recycling silk 2.5.1 Cutting lines 2.5.
2 Recycling silk 2.6 How spiders avoid adhering to their own webs: a mystery partly solved 2.7 Central nervous system basis for web construction 2.8 Summary Chapter 3. Functions of orb web designs 3.1 Introduction 3.2 Correcting common misconceptions about orb webs 3.2.
1 Orbs are neither sieves nor sound detectors 3.2.2 Orb webs are not the pinacle of web evolution 3.2.3 Orbs have never been demonstrated to be "optimum" structures 3.2.4 The trajectories, diameters, and velocities of prey are diverse and poorly known 3.2.
5 Most differences in orb designs are probably not specializations for particular prey 3.2.5.1 Long lists of prey captured seem to argue against strong specialization 3.2.5.2 Strong habitat effects 3.2.
5.3 Data from prey counts generally have serious flaws 3.2.5.4 Measuring "available" prey is also difficult 3.2.5.5 Ontogenetic changes in web design (and lack of such changes) can introduce noise 3.
2.5.6 Ecological settings of studies need to be evolutionarily realistic 3.2.5.7 Flexible construction behavior 3.2.5.
8 Possible exceptions: relative prey specialization 3.2.5.9 A summary regarding prey specialization in orb webs 3.2.6 Interspecific competition for prey is probably not common 3.2.7 Sticky spiral spacing is not uniform 3.
2.8 Orb designs are probably not taxon-specific 3.2.8.1 Species-specificity 3.2.8.2 Effects of intra-specific genetic differences 3.
2.8.3 Genus-specificity? 3.2.8.4 Differences at higher taxonomic levels and a summary 3.2.9 The properties of homologous lines are not invariable 3.
2.9.1 Differences between species 3.2.9.2 Differences within species 3.2.9.
3 Consequences for understanding orb web designs 3.2.10 Correlations between orb design and details of attack behavior are inconsistent 3.2.10.1 Inconsistent relationships 3.2.10.
2 More likely correlations 3.2.11 Orb movements in wind may not be generally significant in intercepting prey (but may affect orb designs) 3.2.11.1 Web movements and the encounter model 3.2.11.
2 Different types of orb web movement in the wind 3.2.11.3 Orb movements in the wind: are they important? 3.2.11.3.1 Prey capture 3.
2.11.3.2 Web damage 3.2.12 Prey are not defenseless: protection from the spider''s own prey 3.2.13 Design details are likely to be selectively important 3.
2.14 Adultophilia: a serious arachnological problem 3.3 How orbs function 3.3.1 Intercepting prey 3.3.2 Functions for non-sticky lines (radii, hub and frame lines) 3.3.
2.1 Stop prey 3.3.2.2 Transmit vibration cues for arousal and orientation 3.3.2.2.
1 Longitudinal vibrations and their amplitudes 3.3.2.2.2 Precision of orientation and the importance (?) of radial organization 3.3.2.2.
3 Types of prey vibration 3.3.2.3 Support the spider and facilitate her movements 3.3.2.4 Primary frame lines: adapt to variable spaces, increase extensibility, and avoid resonant vibrations (?) 3.3.
2.4.1 Theoretical expectations of benefits and costs 3.3.2.4.2 Tests of predictions 3.3.
2.5 Secondary and tertiary frame lines: increase extensibility 3.3.2.5.1 Tests of hypotheses 3.3.2.
6 The hub: mechanical stabilizer, information center, and launching platform 3.3.2.6.1 Attack behavior and hub designs 3.3.2.6.
2 Lines to pull, push against, and grasp while turning 3.3.2.6.3 Tensing (and relaxing) functions of the hub 3.3.2.7 Functions of the tertiary radii 3.
3.2.8 Functions of the temporary spiral 3.3.2.8.1 Patterns in temporary spiral spacing 3.3.
2.8.2 Probable functions of the temporary spiral (hand rail and others) 3.3.2.8.3 Patterns in temporary spiral spacing in orbs and their possible significance 3.3.
2.9 The other side of the coin: how best to fail 3.3.3 Functions for sticky lines 3.3.3.1 Retain prey 3.3.
3.1.1 Selection favors longer retention times 3.3.3.1.2 Means by which prey are retained: adhesion, extension, and resistance to breaking 3.3.
3.1.3 Means of escape: prey behavior 3.3.3.1.4 Spaces between sticky lines 3.3.
3.1.5 An orb''s slant 3.3.3.1.6 "Pulley" attachments of the sticky spiral to the radii 3.3.
3.1.7 Variations in retention times and their consequences 3.3.3.1.8 Summary 3.3.
3.2 Reduce the web''s visibility 3.3.3.2.1 Some insects can see orb webs 3.3.3.
2.2 Does visibility affect prey capture in the field? 3.3.3.2.3 Yellow silk 3.3.3.
3 Other functions 3.3.3.3.1 Survive environmental insults 3.3.3.3.
2 Reduce construction costs and physical constraints 3.3.3.3.2.1 Behavioral costs? .3.3.
3.3.2.1.1 Orb weavers .3.3.3.
3.2.1.2 The special case of uloborids 3.3.3.3.2.
2 Energetic constraints? 3.3.3.3.2.3 Material costs 3.3.3.
3.2.4 The (unknown) costs of vigilance 3.3.3.3.3 Non-orb weavers 3.3.
3.3.4 Defense against predators 3.3.3.3.5 Other possible variables and functions 3.3.
3.4 Planar and non-planar orbs 3.3.4 The function(s) of stabilimenta 3.3.4.1 Egg sac and detritus stabilimenta 3.3.
4.2 Silk stabilimenta 3.3.4.2.1 The hypotheses 3.3.4.
2.2 Problems interpreting the data 3.3.4.2.2.1 Inconsistent support and behavior 3.3.
4.2.2.2 Difficulties with direct measurements I: ecological realism 3.3.4.2.2.
3 Direct measurements II: behavioral contexts, defensive behaviors, species differences 3.3.4.2.2.4 Direct measurements III: inappropriate measurements 3.3.4.
2.2.5 The importance of UV reflectance 3.3.4.2.2.6 The hypotheses are not mutually exclusive 3.
3.4.2.2.7 Some crucial behavioral phenomena are poorly understood 3.3.4.2.
2.8 Comparing many apples with many oranges 3.3.4.2.2.9 Summary of weaknesses of direct measurements 3.3.
4.2.3 Further complications: angles of view, illumination, and background 3.3.4.2.4 Conclusions 3.4 Summary Chapter 4.
Putting pieces together: tradeoffs and remaining puzzles 4.1 Introduction 4.2 "Optimal" orb designs: tradeoffs between functions are difficult to measure 4.2.1 Tradeoffs between functions 4.2.2 The "rare large prey hypothesis": a dominant role for the stopping function? 4.2.
3 Investments in foraging 4.2.4 Overview 4.3 "Multiple trap" design: a new way to view orb webs 4.3.1 Unequal spacing of radii is ubiquitous 4.3.2 Edge-to-hub patterns in sticky spiral spacing are also common--why? 4.
3.2.1 Constraint by cues 4.3.2.2 Speed of attacks 4.3.2.
3 Stopping prey 4.3.2.4 Sticky spiral entanglement 4.3.3 Illumination from exceptions 4.3.3.
1 Low prey velocities 4.3.3.2 Tightly and widely spaced radii 4.3.3.3 Other patterns, other explanations 4.3.
3.3.1 Above vs. below the hub 4.3.3.3.2 Inner edge of the capture zone, "flimsy" orbs, turnbacks 4.
3.4 A limitation of current data: heterogeneity of lines 4.3.5 Conclusions regarding within-web patter.