Publications by authors named "Robert Theis"

We tested three species of praying mantis, Parasphendale affinis, Popa spurca and Sphodromantis lineola, with computer-generated stimuli that differed in size, contrast, configuration and movement pattern to determine the effects of these parameters on visual tracking and striking behavior. Overall, black disks moving erratically against a white background were strong releasers of both behaviors. When stimulus presentation order was randomized by size, P.

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In comparison to other similarly sized mantis species examined in previous studies, Euchomenella macrops has a significantly smaller head, shorter foreleg tibia, but longer prothorax which have been interpreted as specializations for the capture of smaller, slower prey. We tested this conjecture by assessing the rates at which computer generated stimuli elicit visual tracking, approaching, and striking behaviors by adult females. When presented with black disks moving erratically against a white background, strike rate rose progressively as disks enlarged up to 44 deg (visual angle) if the disks moved rapidly (e.

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