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Spider communities were sampled over an artificial gradient of litter depth (created by raking) and compared to those of two other forests exhibiting natural variation in litter depth. More species of spiders were present in areas of greater depth and/or complexity in all sites. Relative abundance of Lycosidae decreased, while relative abundance of Clubionidae, Thomisidae and Gnaphosidae increased over gradients of increasing depth and complexity. Similarity of species composition between areas within a forest was related to site differences in litter depth and structure.As litter depth increased, there were significant changes in prey species richness, litter complexity, and microclimate. Partial correlation analysis of grouped data from early-, mid-, and late season suggests that influential factors change with season. In the early season, prey abundance and temperature variation account for most of the variation in spider species richness. In mid-season, litter complexity and moisture fluctuations appear to influence richness, with complexity relatively more important. In late season, complexity and temperature range were the primary factors, with temperature relatively more influential. The relative importance of these factors in influencing community structure of spiders is discussed.

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Spiders perceive the world using multiple sensory modes, including vibration, vision, and chemical senses, for prey detection and communication. These sensory modes are used in many communication contexts, either individually or in multimodal signaling. Selection for effective signaler-receiver communication and species discrimination is especially strong for these predatory and potentially cannibalistic arthropods, resulting in the evolution of considerable diversity in signaling behaviors. In this paper, we review sensory mechanisms involved in spider signaling and present an overview of recent work done on wolf spiders (Lycosidae) that use multimodal communication (simultaneous visual and vibratory signals) in sexual signals during courtship. The relative importance of visual and vibratory signaling modes, and the use of multiple modes varies among closely related species in the genus Schizocosa, providing a model system for investigating multisensory guidance of complex behavior. Here we examine previous and current research on responses of female spiders to components of male courtship behavior, using several experimental techniques including cue isolation (single sensory modes), video/audio digitization and playback, and cue-conflict (mixed conspecific/heterospecific components) to tease apart elements of multimodal signaling.

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