Caves have long been recognized as a window into the mechanisms of diversification and convergent evolution, due to the unique conditions of isolation and life in the dark. These lead to adaptations and reduce dispersal and gene flow, resulting in high levels of speciation and endemism. The Israeli cave arachnofauna remains poorly known, but likely represents a rich assemblage. In a recent survey, we found troglophilic funnel-web spiders of the genus Tegenaria in 26 caves, present mostly at the cave entrance ecological zone. In addition, we identified at least 14 caves inhabited by troglobitic Tegenaria, which are present mostly in the twilight and dark ecological zones. Ten of the caves, located in the north and center of Israel, are inhabited by both troglophilic and troglobitic Tegenaria. These spiders bear superficial phenotypic similarities but differ in the levels of eye reduction and pigmentation. To test whether these taxa constitute separate species, as well as understand their relationships to epigean counterparts, we conducted a broad geographic sampling of cave-dwelling Tegenaria in Israel and Palestine, using morphological and molecular evidence. Counterintuitively, our results show that the troglobitic Tegenaria we studied are distantly related to the troglophilic Tegenaria found at each of the cave entrances we sampled. Moreover, seven new troglobitic species can be identified based on genetic differences, eye reduction level, and features of the female and male genitalia. Our COI analysis suggest that the Israeli troglobitic Tegenaria species are more closely related to eastern-Mediterranean congeners than to the local sympatric troglophile Tegenaria species, suggesting a complex biogeographic history.

Mygalomorph venom properties and active components, which have importance in medicine, agronomy, venomics, ecology and evolution, have been widely studied, but only a small fraction have been characterised. Several studies have shown inter-individual variation in the composition of venom peptides based on ontogeny, sexual dimorphism, season and diet. However, intra-individual variation in venom composition, which could play a key role in the evolution, diversification and function of toxins, is poorly understood. In this study, we demonstrate significant intra- and inter-individual variation in venom composition in the Australian funnel-web spider Hadronyche valida, highlighting that individuals show different venom profiles over time. Fourteen (four juvenile and ten adult females) funnel-web spiders, maintained under the same environmental conditions and diet, were milked a total of four times, one month apart. We then used reversed-phase high performance liquid chromatography/electrospray ionisation mass spectrometry to generate venom fingerprints containing the retention time and molecular weights of the different toxin components in the venom. Across all individuals, we documented a combined total of 83 individual venom components. Only 20% of these components were shared between individuals. Individuals showed variation in the composition of venom peptides, with some components consistently present over time, while others were only present at specific times. When individuals were grouped using the Jaccard clustering index and Kernel Principal Component Analysis, spiders formed two distinct clusters, most likely due to their origin or time of collection. This study contributes to the understanding of variation in venom composition at different levels (intra-individual, and intra- and inter-specific) and considers some of the mechanisms of selection that may contribute to venom diversification within arachnids. In addition, inter-specific variation in venom composition can be highly useful as a chemotaxonomic marker to identify funnel-web species.