Tidarren argo sp. nov. is described from Yemen. As in its congeners, the male amputates one of his palps before maturation and enters his adult life with one palp only. The new species is shown to adopt exceptional copulatory behaviour. As soon as the male achieves genitalia coupling with his palp, the palp is torn off by the female. The separated gonopod remains attached to the female's epigynum for c. 4 h and apparently continues to function independently. Furthermore, it serves as a mating plug. In the meantime the female feeds on the palpless male. Emasculation synchronizes sexual cannibalism and sperm transfer, and may lengthen the interval between copulations. This unique mating behaviour probably allows continuation of insemination by the dismembered palp and is reported for the ®rst time. Fig. 9. Tidarren cuneolatum (Tullgren), sexual cannibalism after copulation. Male with single right palp still expanded owing to contraction of the prosoma muscles. Body length: female, c. 3 mm; male, 1 mm.

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Butterfly, spider, and plant species richness and diversity were investigated in five different land-use types in Sardinia. In 16 one-hectare plots we measured a set of 15 environmental variables to detect the most important factors determining patterns of variation in species richness, particularly endemicity. The studied land-use types encompassed homogeneous and heterogeneous shrublands, shrublands with tree-overstorey, Quercus forest and agricultural land. A total of 30 butterfly species, among which 10 endemics, and 50 spider (morpho)species, were recorded. Butterfly and spider community composition differed according to land-use type. The main environmental factors determining diversity patterns in butterflies were the presence of flowers and trees. Spiders reacted mainly to habitat heterogeneity and land-use type. Traditional land-use did not have adverse effects on the diversity of butterflies, spiders, or plants. The number of endemic butterfly species per treatment increased with total species richness and altitude. Butterfly and spider richness did not co-vary across the five land-use types. Butterflies were, however, positively associated with plant species richness and elevation, whereas spiders were not. Conclusively, butterflies did not appear to be good indicators for spider diversity and species richness at the studied sites.

ABSTRACT. This study elucidates the homology of elements of the male palps in the spider family Theridiidae. We survey and illustrate 60 species from 29 out of the 86 currently recognized genera representing all subfamilies. The study is buttressed by a phylogenetic framework, and uses a new method to evaluate critically competing homology hypotheses based on various criteria. Among the classic criteria for homology, topology performed better than special similarity, and much better than function. Guided by those results, we propose names for and correspondences among the broad diversity of theridiid palpal tegular sclerites. We discuss the phylogenetic utility and distribution of key palpal characteristics, and evaluate existing evolutionary hypotheses of the theridiid palp and its components.