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The fibers are pulled out by the calamistrum, a comblike set of bristles on the jointed tip of the cribellum, and combined into a composite woolly thread that is very effective in snagging the bristles of insects. The earliest spiders had cribella, which produced the first silk capable of capturing insects, before spiders developed silk coated ...
Spider behavior refers to the range of behaviors and activities performed by spiders. Spiders are air-breathing arthropods that have eight legs and chelicerae with fangs that inject venom . They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms [ 1 ] which is reflected in their ...
Secondary homology is implied by parsimony analysis, where a character state that arises only once on a tree is taken to be homologous. [20] [21] As implied in this definition, many cladists consider secondary homology to be synonymous with synapomorphy, a shared derived character or trait state that distinguishes a clade from other organisms.
Silk: spiders, silk moths, larval caddis flies, and the weaver ant all produce silken threads. [145] The praying mantis body type – raptorial forelimb, prehensile neck, and extraordinary snatching speed - has evolved not only in mantises but also independently in neuropteran insects Mantispidae. [146]
By the Jurassic period, the sophisticated aerial webs of the orb-weaver spiders had already developed to take advantage of the rapidly diversifying groups of insects. A spider web preserved in amber, thought to be 110 million years old, shows evidence of a perfect "orb" web, the most famous, circular kind one thinks of when imagining spider webs.
More narrowly, the study of spiders alone (order Araneae) is known as araneology. [1] The word "arachnology" derives from the Greek words ἀράχνη, arachnē, "spider"; and -λογία, -logia, "the study of a particular subject". The greek word for "spider" itself refers to Arachne, the female protagonist of an ancient tale of the Greek ...
Top: An ant in Mozambique Bottom: An ant-mimicking spider, Myrmarachne Ant mimicry or myrmecomorphy is mimicry of ants by other organisms; it has evolved over 70 times. Ants are abundant all over the world, and potential predators that rely on vision to identify their prey, such as birds and wasps, normally avoid them, because they are either unpalatable or aggressive.
The extant chelicerates comprise two marine groups: Sea spiders and horseshoe crabs, and the terrestrial arachnids. These have been thought to be related as shown below. [41] [44] (Pycnogonida (sea spiders) may be excluded from the chelicerates, which are then identified as the group labelled "Euchelicerata". [46]) A 2019 analysis nests ...