In the last 15 years understanding of the higher systematics of Araneae has changed greatly. Large classical superfamilies and families have turned out to be polyor paraphyletic; posited relationships were often based on sym­ plesiomorphies. In this brief review we summarize current taxonomic and phylogenetic knowledge and suggest where future efforts might profitably be concentrated. We lack space to discuss fully all the clades mentioned, and the cited numbers of described taxa are only approximate. Other aspects of spider biology have been summarized by Barth (7), Eberhard (47), Jackson & Parks (72), Nentwig (l05), Nyffeler & Benz ( 1 06), Riechert & Lockley ( 134), Shear ( 1 49) and Turnbull ( 160).

Systematics and Evolution of Spiders (Araneae)

Inherited bacteria have come to be recognised as important components of arthropod biology. In addition to mutualistic symbioses, a range of other inherited bacteria are known to act either as reproductive parasites or as secondary symbionts. Whilst the incidence of the α-proteobacterium Wolbachia is relatively well established, the current knowledge of other inherited bacteria is much weaker. Here, we tested 136 arthropod species for a range of inherited bacteria known to demonstrate reproductive parasitism, sampling each species more intensively than in past surveys. The inclusion of inherited bacteria other than Wolbachia increased the number of infections recorded in our sample from 33 to 57, and the proportion of species infected from 22.8% to 32.4%. Thus, whilst Wolbachia remained the dominant inherited bacterium, it alone was responsible for around half of all inherited infections of the bacteria sampled, with members of the Cardinium, Arsenophonus and Spiroplasma ixodetis clades each occurring in 4% to 7% of all species. The observation that infection was sometimes rare within host populations, and that there was variation in presence of symbionts between populations indicates that our survey will itself underscore incidence. This extensive survey demonstrates that at least a third of arthropod species are infected by a diverse assemblage of maternally inherited bacteria that are likely to strongly influence their hosts' biology, and indicates an urgent need to establish the nature of the interaction between non-Wolbachia bacteria and their hosts.

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The diversity of reproductive parasites among arthropods: Wolbachia do not walk alone

With almost 40 000 species, the spiders provide important model systems for studies of sociality, mating systems, and sexual dimorphism. However, work on this group is regularly constrained by diff...

Identifying spiders through DNA barcodes

Spiders (Araneae) spin high-performance silks from liquid fibroin proteins. Fibroin sequences from basal spider lineages reveal mosaics of amino acid motifs that differ radically from previously described spider silk sequences. The silk fibers of Araneae are constructed from many protein designs. Yet, the repetitive sequences of fibroins from orb-weaving spiders have been maintained, presumably by stabilizing selection, over 125 million years of evolutionary history. The retention of these conserved motifs since the Mesozoic and their convergent evolution in other structural superproteins imply that these sequences are central to understanding the exceptional mechanical properties of orb weaver silks.

https://science.sciencemag.org/content/sci/291/5513/2603.full.pdf

Extreme Diversity, Conservation, and Convergence of Spider Silk Fibroin Sequences

Art. 1 As pilhas e baterias que contenham em suas composições chumbo, cádmio, mercúrio e seus compostos, necessárias ao funcionamento de quaisquer tipos de aparelhos, veículos ou sistemas, móveis ou fixos, bem como os produtos eletro-eletrônicos que as contenham integradas em sua estrutura de forma não substituível, após seu esgotamento energético, serão entregues pelos usuários aos estabelecimentos que as comercializam ou à rede de assistência técnica autorizada pelas respectivas indústrias, para repasse aos fabricantes ou importadores, para que estes adotem, diretamente ou por meio de terceiros, os procedimentos de reutilização, reciclagem, tratamento ou disposição final ambientalmente adequada.

Ministério do meio ambiente

The orb-weaver genus Mecynogea, the subfamily Metinae and the genera Pachygnatha, Glenognatha and Azilia of the subfamily Tetragnathinae north of Mexico (Araneae: Araneidae)

The genera of the spider family Theridiidae

The Spider Genus Latrodectus (Araneae, Theridiidae)

not yet certain of the limits and diagnoses tions. Next to the Linyphiidae, the Araneiof the numerous araneid genera. The gedae are most difficult to determine at the nus Argiope is an exception; the species present time, but fragmentation of the belonging to it are readily placed. As the family into many meaningless genera, as in work progresses, I expect that the relative the Linyphiidae, luckily is less of a probimportance of the various characters will lem in the study of the Araneidae.

Herbert W. Levi

Papers

Systematics and Evolution of Spiders (Araneae)

The orb-weaver genus Mecynogea, the subfamily Metinae and the genera Pachygnatha, Glenognatha and Azilia of the subfamily Tetragnathinae north of Mexico (Araneae: Araneidae)

The genera of the spider family Theridiidae

The Spider Genus Latrodectus (Araneae, Theridiidae)

The spider genera Gea and Argiope in America (Araneae: Araneidae)