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The microstructural characteristics of the silk-spinning apparatus and its ecological significance in the coelotine spider Paracoelotes spinivulva were examined by field emission scanning electron microscopy, with the goal of understanding the properties and the evolutionary origins of these silk constructs. The silk apparatuses of this spider were...
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... one to two pairs of ampullate spigots in both sexes, three pairs of tubuliform spigots in females, and 50 -60 (female) or 80 -90 (male) pairs of aciniform spigots are connected on the middle spinnerets. An additional two pairs of tubuliform spigots in females, and 70 -80 (female) or 100-120 (male) pairs of aciniform spigots are located on the posterior spinnerets (Table 1). ...Similar publications
Although the basic taxonomic characteristics usually remain unchanged, some spinning apparatuses undergo consistent adaptive variations. As the presence of additional protuberances known as nubbins and tartipores have caused disagreements regarding some Araneidae spiders, more detailed definitions on the cuticular structures have recently been prop...
Citations
... The arrangement and number of spigots vary between the species, sex, and age of the spider. [3][4][5][6] It is likely that the use of silk evolved once in spiders, and then over time has evolved into multiple different forms to fulfill different applications or functions for the spider. ...
... Further details of the arrangement of the silk spigots are beyond this review but have been characterized in a number of papers and books for a wide number of species. 4,6,36 In the following, we discuss the spidroin sequences and their properties; in this sense, we compare all the silks to one another. ...
Spider silk is of great interest because of its extraordinary physical properties, such as strength and toughness. Here we discuss how these physical properties relate to the way in which spiders have utilized this material in prey capture, forcing its evolution to a high-performance fiber. Female spiders can produce up to seven different types of silk, and all these have different physical properties, which relate to their various functions. The variation in properties are due to underlying differences in the proteins making up these silks. As our understanding of spider silk has increased in the recent years, it has been possible to produce recombinant versions of the respective proteins. Recombinant proteins open up the potential to produce synthetic silk fibers with properties similar to those of the natural spider silk threads.
Spiders (order Araneae) rely on their silks for essential tasks, such as dispersal, prey capture, and reproduction. Spider silks are largely composed of spidroins, members of a protein family that are synthesized in silk glands. As needed, silk stored in silk glands is extruded through spigots on the spinnerets. Nearly all studies of spider silks have been conducted on females; thus, little is known about male silk biology. To shed light on silk use by males, we compared silk gene expression profiles of mature males to those of females from three cob-web weaving species (Theridiidae). We de novo assembled species-specific male transcriptomes from Latrodectus hesperus, Latrodectus geometricus, and Steatoda grossa followed by differential gene expression analyses. Consistent with their complement of silk spigots, male theridiid spiders express appreciable amounts of aciniform, major ampullate, minor ampullate, and pyriform spidroin genes but not tubuliform spidroin genes. The relative expression levels of particular spidroin genes varied between sexes and species. Because mature males desert their prey-capture webs and become cursorial in their search for mates, we anticipated that major ampullate (dragline) spidroin genes would be the silk genes most highly expressed by males. Indeed, major ampullate spidroin genes had the highest expression in S. grossa males. However, minor ampullate spidroin genes were the most highly expressed spidroin genes in L. geometricus and L. hesperus males. Our expression profiling results suggest species-specific adaptive divergence of silk use by male theridiids.
