Avoiding attack : the evolutionary ecology of crypsis, warning signals, and mimicry

Cover
Avoiding Attack: The Evolutionary Ecology of Crypsis, Aposematism, and Mimicry
Copyright
Dedication
Acknowledgements
Contents
Plates
Introduction
	Chapter summary
	The sequence of a predator–prey encounter and investment across multiple defences
Chapter 1. Background matching
	1.1 Introduction, definition, mechanism, and chapter overview
	1.2 Empirical evidence of background matching
	1.3 The evolution of background matching
		1.3.1 Polymorphism of background-matching forms
		1.3.2 Definitions related to frequency-dependent predation
		1.3.3 Positive selection for polymorphism
	1.4 Co-evolutionary considerations
		1.4.1 Search image formation as a means of enhancing detection of cryptic prey
		1.4.2 Control of search rate to enhance detection of cryptic prey
		1.4.3 Comparing search image and search rate mechanisms
	1.5 Ecological considerations
		1.5.1 Optimizing of background matching for a single appearance in visually variable backgrounds
		1.5.2 Changing appearance to enhance background matching
		1.5.3 Combining background matching with other functions
	1.6 Unresolved issues and future challenges
Chapter 2. Disruptive camouflage
	2.1 Introduction and overview
	2.2 Examples of disruptive camouflage
	2.3 The multiple mechanisms of camouflage by disruption
		2.3.1 Disruption of edge detection processes
		2.3.2 Disruption of perceptual organization: grouping and segmentation
		2.3.3 Disruption of object detection and recognition
	2.4 Identifying and quantifying disruptive camouflage
	2.5 The relationship between disruption and other forms of protective coloration
		2.5.1 Background matching ( Chapter 1)
		2.5.2 Aposematism ( Chapter 9)
		2.5.3 Distractive, divertive, and deflective markings ( Chapter 11)
		2.5.4 Dazzle ( Chapter 12)
	2.6 The ecology of disruption
	2.7 Unresolved issues and future challenges
Chapter 3. Countershading
	3.1 What is countershading?
	3.2 Examples and taxonomic distribution of countershading camouflage
	3.3 Countershading camouflage mechanisms
	3.4 Evolution
		3.4.1 Evolutionary history of countershading
		3.4.2 Evolutionary history of counterillumination
	3.5 Costs of countershading and counterillumination camouflage
	3.6 Developmental genetics of countershading
	3.7 The evolutionary ecology of countershading
	3.8 Countering countershading and counterillumination adaptations
	3.9 Unresolved issues and future challenges
Chapter 4. Transparency
	4.1 Definition and introduction
	4.2 The distribution of transparency across habitats
	4.3 How transparency influences ease of detection
		4.3.1 Transparent objects still reflect and refract
		4.3.2 How transparent organisms influence polarization of light
		4.3.3 How transparent organisms interact with light outside our visual range
		4.3.4 Considering how Snell’s window affects detection of transparent organisms
	4.4 Evolutionary considerations
		4.4.1 Constraints of transparency: some parts of an organism cannot be made transparent
		4.4.2 Silvering as an alternative form of crypsis
	4.5 Ecological influences
		4.5.1 Imperfect transparency can be effective at low light levels
	4.6 Co-evolutionary considerations
	4.7 Unresolved issues and future challenges
Chapter 5. Secondary defences
	5.1 Introduction and overview of the chapter
	5.2 Evolution of secondary defence
		5.2.1 Self and others: social evolution of defences
		5.2.2 Costs
	5.3 Consequences of variation in costs of secondary defence
		5.3.1 Defence costs might lead to cheating
	5.4 Ecology
		5.4.1 Ecology-defence correlations
		5.4.2 Ecological and evolutionary consequences of secondary defences
	5.5 Co-evolutionary considerations
		5.5.1 Evidence for predator–prey co-evolution
		5.5.2 Co-evolution—an explanation for defence diversity?
	5.6 Unresolved issues and future challenges
Chapter 6. Aposematism
	6.1 What is aposematism?
	6.2 Characteristics of aposematic organisms
		6.2.1 What characterizes an aposematic organism?
		6.2.2 Aposematic signals are (usually) primarily visual
		6.2.3 Visual aposematic signals are often conspicuous, sometimes predictably so
		6.2.4 But aposematic conspicuousness does not always exclude crypsis
		6.2.5 Distinctiveness and simplicity of visual traits may be primary requirements of aposematic colour patterns
		6.2.6 Aposematism is primarily a phenomenon in animals, but it may be present in other groups
		6.2.7 Aposematism is probably a rare phenomenon in animals
	6.3 Evolution of aposematism
		6.3.1 Initial evolution of aposematic signals
			1) Absence of predators, relaxed selection, and drift
			2) Exploitation of receiver biases
			3) Co-evolution of aposematic signals and receiver biases
			4) Aggregation and family grouping are causal in the initial evolution of aposematism
			5) Gradual evolution of aposematic coloration
			6) Initial evolution is more easily explained with physical not chemical defences
			7) Ecological conditions lower the costs of initial aposematic coloration
	6.4 Maintenance of aposematic signalling
	6.5 Ecology of aposematism
		6.5.1 Ecology 1: Effects of predictable variation in predator communities
		6.5.2 Ecology 2: Aposematic coloration and its relationship to niche and behaviour
		6.5.3 Ecology 3: Variation and honesty in warning coloration
			1) Relaxed and disruptive selection and variable costs
			2) Honest signalling as an explanation of signal variation
	6.6 Co-evolution of aposematic signals and receiver psychology
	6.7 Future work and conclusions
Chapter 7. The evolution and maintenance of Müllerian mimicry
	7.1 Introduction
		7.1.1 Müller’s theory
	7.2 Examples
		7.2.1 Neotropical butterflies
		7.2.2 Wasps
		7.2.3 Millipedes
		7.2.4 Catfish
		7.2.5 Bumblebees
		7.2.6 Poison frogs
	7.3 Müller’s theory revisited
	7.4 Evidence for Müller’s hypothesis
		7.4.1 Field assessments of the benefits of adopting a common warning signal
		7.4.2 Direct observations of predators reacting to warningly coloured unpalatable prey
	7.5 Questions and controversies
		7.5.1 Do predators take a fixed n in aversion learning?
		7.5.2 Is one signal better than two?
		7.5.3 How does Müllerian mimicry evolve?
		7.5.4 Why are mimetic species variable in form between areas?
		7.5.5 How can multiple Müllerian mimicry rings co-exist?
		7.5.6 What is the nature of selection when the species differ in unprofitability?
	7.6 Overview
Chapter 8.  Advertising elusiveness
	8.1 Introduction and definition
	8.2 Empirical evidence of elusiveness signals
		8.2.1 Stotting by gazelle
		8.2.2 Upright stance by hares
		8.2.3 Vervet monkey alarm calls to leopards
		8.2.4 Other potential signals by mammals
		8.2.5 Singing and distress calling by birds
		8.2.6 Visual signalling of contrastingly coloured birds’ tails
		8.2.7 Willow tit alarm calls and attack preferences by pygmy owl
		8.2.8 Visual displays by lizards
		8.2.9 Predator inspection by fish
		8.2.10 Summary of empirical evidence
	8.3 Evolution
		8.3.1 Theoretical stability of signalling that an approaching predator has been detected (perception advertisement)
		8.3.2 Theoretical stability of signalling that the prey individual is intrinsically difficult to catch (pursuit deterrent signals)
		8.3.3 Summary of theoretical work
		8.3.4 Empirical explorations of evolutionary trajectories
	8.4 Ecology
	8.5 Co-evolutionary considerations
	8.6 Unresolved issues and future challenges
Chapter 9. Batesian mimicry and masquerade
	9.1 Introduction and overview of the chapter
	9.2 Examples of protective deceptive mimicry
		9.2.1 Masquerade
		9.2.2 Batesian mimicry
	9.3 The origin of protective mimicry: selection or shared ancestry?
	9.4 The evolution of protective deceptive mimicry
		9.4.1 Evidence that masquerading prey dupe predators
		9.4.2 Evidence that Batesian mimics dupe predators
			Laboratory studies
			Field studies
		9.4.3 Evidence that the success of the mimic generally requires the presence of the model
		9.4.4 The relative (and absolute) abundance of the model and mimic affect the rate of predation on these species
		9.4.5 The distastefulness of the model affects the rate of predation on the model and mimic
		9.4.6 The model can be simply difficult to catch rather than noxious on capture
		9.4.7 The success of mimicry is dependent on the availability of alternative prey
		9.4.8 Frequency-dependent selection on Batesian and masquerader mimics can lead to mimetic polymorphism
		9.4.9 Sex-limited polymorphic mimicry
		9.4.10 The genetics of polymorphic Batesian mimicry
	9.5 Ecological and phylogenetic considerations
	9.6 Associated phenomena in the evolution of Batesian mimicry and masquerade
		9.6.1 Tastes and toxins: the role of prey rejection
		9.6.2 Imperfect mimicry and the limits of natural selection
		9.6.3 What selective factors influence behavioural mimicry?
	9.7 Overview
Chapter 10. Startling predators
	10.1 What do we mean by startle?
	10.2 Empirical evidence for the defence
		10.2.1 Sound production in insects
		10.2.2 Clicking sounds of aquatic organisms
		10.2.3 Posture, appearance, and inking in cuttlefish and squid
		10.2.4 Adult lepidopteran wing patterns
		10.2.5 Posture and stridulation in mantids
		10.2.6 Summary of empirical evidence
	10.3 The evolution of startle defence
		10.3.1 The mechanism underlying startle
		10.3.2 Satyric mimicry
		10.3.3 Evolutionary history, genetic control, and environmental plasticity of startle signals
		10.3.4 Selective pressures
	10.4 Ecological aspects of startle defences
	10.5 Co-evolutionary considerations in startle defences
	10.6 Unresolved issues and future challenges
Chapter 11. Deflecting the point of attack
	11.1 Overview
	11.2 How deflecting traits work
	11.3 The taxonomic distribution of deflecting traits
		11.3.1 Adult lepidopteran eyespots
		11.3.2 Lizard’s tails
		11.3.3 Eyespots on fish
		11.3.4 Tadpole tails
		11.3.5 Weasels’ tails
		11.3.6 Caterpillars
		11.3.7 Web decorations in orb spiders functioning in distraction
		11.3.8 Distractive behaviour by breeding adult vertebrates
		11.3.9 Summary of current knowledge of the distribution of deflective traits
	11.4 The evolution of deflective traits
		11.4.1 Evolutionary history
		11.4.2 Evidence for costs to deflective traits
		11.4.3 Linkage with other anti-predatory defences
		11.4.4 Phylogenetic studies
	11.5 Ecology
	11.6 Co-evolutionary considerations
	11.7 Future challenges
Chapter 12. Dazzle camouflage
	12.1 Camouflage in motion?
	12.2 Examples of dazzle
		12.2.1 Dazzle ships
		12.2.2 Zebras
		12.2.3 Squamate reptiles
		12.2.4 Cephalopods
		12.2.5 Other groups
	12.3 How does dazzle camouflage work?
		12.3.1 How can coloration affect perception of speed and trajectory?
		12.3.2 The form of dazzle camouflage: pattern contrast
		12.3.3 The form of dazzle camouflage: pattern texture and orientation
		12.3.4 Dynamic dazzle
	12.4 The evolution of dazzle
	12.5 The costs and benefits of dazzle
	12.6 The ecology of dazzle
	12.7 Future challenges in dazzle camouflage research
Chapter 13. Thanatosis
	13.1 Introduction and overview of the chapter
	13.2 Distribution
	13.3 Form: the mechanisms involved
		13.3.1 What is the evidence that thanatosis offers protection from predators?
		13.3.2 Does thanatosis ever function in contexts other than against predators?
	13.4 Evolutionary function: a cost/benefit approach
	13.5 Ecological considerations
	13.6 Co-evolutionary considerations
	13.7 Unresolved issues and future challenges
Synthesis
References
Index