George W. Uetz Professor Ph.D., University of Illinois Animal Behavior, Behavioral Ecology, & Arachnology

Wolf spider communication project - Video Digitization and Playback

 We use video digitization and playback techniques in our research.  These techniques were developed in our lab with former student Dr. David Clark (Alma College) (Clark & Uetz 1990; 1992; 1993).  They are based on the discovery that jumping spiders (Salticidae) and wolf spiders (Lycosidae) perceive video images of other spiders and interpret them as real (i.e., they attack images of prey, display to images of potential mates and avoid images of predators). 

            Experiments with Schizocosa examine the relationship between visual and vibration signals produced by “senders” (males) and the information they convey to “receivers” (females). Use of combined video / audio playback (Uetz & Roberts 2002) makes it possible to experiment with specific aspects of multi-modal signals, and gain insights about the sensory cues used by the recognition “program” encoded within the simple nervous system of the spider.

            Using video capture and digitization, we can experimentally manipulate the essential elements of male signals used in courtship – morphology (elaborate male secondary characters, such as leg tufts) and behavior (complex movements, such as leg tapping and waving displays) – then play these back to females and observe their responses.

  Click here to view a video clip of a female Schizocosa viewing a computer digitization (The video file is a 1.2MB .avi download that will open in a new window)

             Previous work has focused on the role of leg tufts in male Schizocosa ocreata , and has found that manipulation of tuft presence/absence and size (using both surgical alteration and video image digitization) influences species recognition and female receptivity (Scheffer et al. 1996; McClintock & Uetz 1996; Hebets & Uetz 2000).

Video Images

Control Tufts	No Tufts	Enlarged Tufts	Reduced Tufts

             These images are captured still frames of a male courtship video that we use in playback studies.  They are identical in all respects except for the size of male tufts, which we have modified digitally (as Liz Smith is doing in the photo above). Playback studies have shown that female receptivity varies with the presence/absence and size of these tufts (McClintock & Uetz 1996; Uetz 2000), suggesting that they are a criterion for female mate choice. We also have evidence that these conspicuous tufts serve both as “amplifiers” that increase the efficacy of visual displays in species recognition, and as “handicaps” that serve as male quality indicators (Hebets & Uetz 2000; Uetz 2000; Uetz et al. 2002).

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 Research: 1. Wolf Spider Research | 2. Colonial Web-Building Spiders Research | 3. El Niño Influence on Colonial Web-Building Spiders. |  4. Impact of a Ecosystem Disturbance on Spider Populations and Communities