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Phylogenetic relationships and estimated dates of origin, plus distributional, ecological and morphological data for salticid genera were used to examine a series of hypotheses related to the evolution of the Australian salticid fauna. Though independent, the time patterns of evolution of genera in Australia and South America were similar, while that for Northern Hemisphere taxa differed. In each case the production of new genera occurred during the warmer parts of the mid Tertiary but not during cooler and drier times. Asian elements entered Australia as early as 31 million years ago, long before the collision of the Australasian and Asian continental plates. Endemic and derivatives of Asian genera were similarly distributed across Australian biomes. However, arriving taxa were more successful when conditions matched their mesic origins (tropical), but less so when different (temperate). While endemic genera often extended their ranges into drier environments by increasing the number of species, recent arrivals did so by extending the range of individual species. Maximum Parsimony analyses of a range of presumed adaptive, morphological and ecological characters showed these did not reflect genus-level processes; however, the analysis did show all endemic genera had mesic origins. Knowledge of the biology of the charismatic Australian jumping spiders is limited. This study found that the evolution of new genera in Australia, South America and the Northern Hemisphere followed, in each case, the local pattern of mid-Tertiary climate changes. Further, the present Australian salticid fauna shows a successful diversity of many, often large, genera with radiations of species covering the entire range of Australian habitats, and probably can only adapt very slowly to modern continental climate change. Photo by B. J. Richardson. [ABSTRACT FROM AUTHOR]

Among spiders, some species could be qualified as colonial. Individuals may live alone or in colonies where each spider exploits its own capture web in a communal network. We compared solitary with colonial life in Cyrtophora female populations from South-East Sicily in 1992 and 1993. We used 6 parameters to describe and compare the populations: spider size, web size, egg production, prey captured, presence of kleptoparasites and their size.¶ Spiders living in colonies did not differ in size from solitary spiders.¶ The webs of colonial spiders were smaller than those of solitary spiders.¶ The number of prey captured and their size did not differ between the two types of spiders.¶ Solitary spiders produced more eggs than colonial individuals.¶ Kleptoparasite spiders Argyrodes gibbosus were more numerous in the webs of solitary spiders than in the webs of colonial spiders and there were more solitary webs infested by kleptoparasites in 1992. The kleptoparasites were larger in colonial webs than in solitary ones. Another species of spider, Holocnemus pulchei, spun its own web in the network of the web of Cyrtophora. The number of Holocnemus per web did not differ between solitary and colonial Cyrtophora.¶ Results are discussed by referring to what it is known in other temporarily social spiders. [ABSTRACT FROM AUTHOR]