Spiderwebs and Silk: Tracing Evolution From Molecules to Genes to PhenotypesThis book links the molecular evolution of silk proteins to the evolution and behavioral ecology of web-spinning spiders and other arthropods. Craig's book draws together studies from biochemistry through molecular genetics, cellular physiology, ecology, and behavior to present an integrated understanding of an interesting biological system at the molecular and organizational levels. |
Contents
Silk Proteins Breakdown and Evolutionary Pathways | 3 |
Current hypotheses suggest that fibrous proteins produced by the Chelicerata and Hexapoda evolved independently | 7 |
Comparative phylogenetic analyses pinpoint the taxa most likely to yield insight into the origins and biology of silkproducing systems | 14 |
The ability to secrete fibrous proteins is a primitive character of the hexapods and first evolved in the Diplura | 18 |
The ability to secrete silk fibroins correlates with the evolution of spinning behavior | 20 |
The structural organization of spider silk is correlated with the evolution of a muscular and innervated spinneret | 25 |
a systemic gland pathway and a surficial gland pathway | 27 |
Summary | 29 |
Web visibility is determined by specific webbackground combinations in specific ambient light conditions | 103 |
Visible and invisible webs might have evolved in parallel | 106 |
Insect Color Vision Is a Potential Selective Factor on the Evolution of Silk Chromatic Properties and Web Design | 108 |
Detection of colored objects is based on their contrast against the background | 113 |
The perceptions of chromatic contrast and achromatic contrast are independent processes | 114 |
Webs of ancestral and derived spiders differ in their spectral reflectance | 115 |
Do the differences in UVreflection of silks result from selective effects of insect color vision? | 122 |
Insect Learning Capacity Is a Potential Selective Factor in the Evolution of Silk Color and the Decorative Silk Patterns Spun by Spiders | 123 |
The Comparative Architecture of Silks Fibrous Proteins and Their Encoding Genes in Insects and Spiders | 31 |
The known silk fibroins and fibrous glues are encoded by members of the same gene family | 32 |
Most silk fibroins contain crystalline and noncrystalline regions | 35 |
All of the sequenced fibroin silks Fhc MA and Flag are made up of hierarchically organized repetitive arrays of amino acids | 38 |
Fhc fibroin genes and perhaps MA genes are characterized by a similar molecular genetic architecture of two exons and one intron but the organizati... | 41 |
The Flag Ser and BR genes are made up of multiple exons and introns | 43 |
Sequences coding for crystalline and noncrystalline protein domains are integrated in the repetitive regions of Fhc and MA exons but not in the prote... | 46 |
Codon bias structural constraint point mutations and shortened coding arrays are alternative means of stabilizing precursor mRNA transcripts | 47 |
Differential regulation of gene expression and selective splicing may allow rapid adaptation of silk functional properties to different environments | 48 |
Summary | 49 |
The Mechanical Functions of Silks and Their Correlated Structural Properties | 51 |
Ancestral araneomorph spiders spin dry capture silks into irregular webs derived araneomorph spiders here the Orbiculariae spin dry and wet capture... | 55 |
The Orbiculariae spin nets that are suspended under tension and that approximate minimum volume architectures | 60 |
Web function is determined by the interaction between web architecture and the material properties of silks | 63 |
The webs and silks spun by the ancestral Deinopoidea are stiff their ability to both withstand prey impact and to retain prey is a function of fiber stre... | 68 |
The diversification of the Araneoidea correlates with a shift in web functional mechanism | 69 |
Silk fibroins produced by derived spiders contain either highly oriented crystalline regions or no crystalline regions at all | 70 |
Despite the advantages of araneoid webs and silks the cribellate spiders have persisted through evolution | 81 |
Summary | 82 |
Insect Spatial Vision Is a Potential Selective Factor on the Evolution of Silk Achromatic Properties and Web Architecture | 84 |
Contrast resolution is the prerequisite of object detection | 86 |
Insects possess a high temporal resolution capacity | 87 |
Motion parallax cues provide the insect with depth information | 90 |
Insect vision and flight maneuverability function as potential selective forces on silk and web properties | 91 |
Distorted and oscillating webs may enhance insect interception | 92 |
The translucent properties of frame MA and spiral Flag silk minimize contrast between webs and their background | 96 |
Insects response to webs is independent of ambient light conditions | 98 |
Insect responses to visual cues are either innate or learned | 124 |
Some silks possess particular spectral or spatial features that vary with ambient light | 125 |
Some silks and webs possess particular spectral or spatial features that might be attractive to insects | 129 |
Drosophila may be attracted to UVreflecting silk due to their spontaneous openspace response | 134 |
Studies on web avoidance learning show that bees are able to dissociate color cues from the information with which it is paired | 136 |
Web decorations attract prey and their variable orientations may disrupt insect pattern learning | 141 |
Decorative silk patterns that attract prey are also likely to attract the predators of spiders | 152 |
InterGland Competition for Amino Acids and the ATP Costs of Silk Synthesis | 156 |
The amino acids organisms synthesize are those needed in large quantities and on a predictable basis | 157 |
The central metabolic pathways provide a common currency ATP through which the costs of protein synthesis can be compared | 158 |
The amino acid compositions of silks spun by arthropods vary in proportions of alanine glycine and serine | 165 |
Direct comparison of amino acid costs suggests that dragline MA silks produced by araneomorph spiders are more costly than cocoon Fhc silks prod... | 167 |
Comparison of MA silk produced by ancestral and derived species suggests a trend toward reduced silk costs among the cribellates and between the ... | 168 |
Spider silk glands may have evolved through intragland competition for amino acids that the spiders synthesize | 169 |
Gene organization that allows selective expression andor selective editing of proteins may allow spiders to reduce silk costs during periods of food str... | 171 |
The ability to recycle silks allows the araneoids to reduce the metabolic costs of producing silk | 172 |
A OneDimensional Developmental System and LifeLong Silk Synthesis May Preclude the Evolution of Higher Eusociality in Spiders | 173 |
Multiple selective factors favor the evolution of eusociality | 174 |
Insects have three developmental pathways but spiders have only one | 179 |
Ecdysteroids regulate metamorphosis in the absence of JH | 181 |
Ecdysteroids regulate silk synthesis in the Lepidoptera | 183 |
JH inhibits the action of ecdysone | 185 |
Ecdysone may regulate silk synthesis in some spider glands but silk production in the MA gland seems to be neurally regulated | 188 |
Developmental flexibility may be a precondition for the evolution of caste systems | 189 |
Conclusion | 191 |
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Common terms and phrases
aciniform alanine amino acids ancestral Ap-Fhc Araneae araneoid Araneoidea araneomorph araneomorph spiders argentata Argiope Argiope argentata background bees behavior bright chapter characterized cocoon silk Coddington color contrast correlated Craig cribellate crystalline decorated Deinopoidea derived domains dragline silks droplets ecdysone effects Embiidina encode eusociality evolution of silk evolutionary evolved exons fiber fibroin fibrous proteins figure Flag silk flagelliform foraging function genetic gland silks glycine Hayashi and Lewis holometabolous Hymenoptera insects intercepted introns Kovoor larvae Lehrer Lepidoptera light minor ampullate molecular mori morphology motifs Mygalomorphae Nijhout noncrystalline Opell organization pathway patterns phylogeny pigments prey produce silks properties protein glues receptor reflectance regions result Riekel selection sequences serine silk genes silk glands silk proteins silk synthesis silks and fibrous silks produced silks spun species spectral spider silk spin spinnerets αΊ-sheet structure taxa threads types of silks Uloboridae viscid wavelengths web decorations webs spun XRD-pattern
Popular passages
Page 203 - Denny, MW (1980), Silks - their properties and functions, in : The Mechanical Properties of Biological Materials (Vincent, JFV, Currey, JD, Eds.), Cambridge: Cambridge University Press, 245-271.β
Page 200 - S. (1994) Sequence conservation in the C-terminal region of spider silk proteins (Spidroin) from Nephila clavipes (Tetragnathidae) and Araneus bicentenarius (Araneidaie)./.β
Page 203 - In Spiders: webs, behavior and evolution, (ed. WA Shear), Stanford University Press, Stanford, Calif., pp.β
References to this book
Fibrous Proteins: Amyloids, Prions and Beta Proteins John M. Squire,Andrey Kajava,David A.D. Parry No preview available - 2006 |