-We experimentally tested visual cues used by the mantid (Tenodera ardifolia) in learning aversion to noxious prey. For 2 wk, we repeatedly presented mantids with milkweed bugs (Oncopeltusfasicatus) that were fed cardenolide-containing seeds of the milkweed, Asclepias syriaca. Milkweed bugs were painted with one of four color patterns: solid black, solid orange, half black and half orange, and alternately striped with orange and black. A fifth treatment included naturally colored (orange and black mottling), unpainted bugs. As mantids gained experience with unpalatable prey, they became significantly more hesitant to strike and struck less frequently. Furthermore, our data suggest mantids presented prey with broken patterns hesitate to strike longer than those presented prey with solid patterns. We conclude that this invertebrate predator can learn to delay attacks on distasteful prey and that pattern in aposematic coloration may influence aversion learning by mantids. INTRODUCTION There is accumulating evidence for the ability of insects, and invertebrates in general, to learn. Flies have been shown to exhibit a wide array of learning phenomena. For example, induced responsiveness to a second water stimulus when preceded by sucrose stimulation was demonstrated in the blowfly Phormia regina (Dethier et al., 1965) and classical conditioning of the proboscis extension reflex was shown with the same species (Nelson, 1971). Vargo and Hirsch (1982) demonstrated induced responsiveness similar to that described by Dethier et al. (1965) but with Drosophila melanogaster. Classical conditioning with regard to the proboscis extension reflex has also been shown for D. melanogaster (Holliday and Hirsch, 1986). Bees also possess a considerable ability to learn; classical conditioning of proboscis extension was demonstrated in Apis mellifera (Bitterman et al., 1983); A. mellifera also exhibited aversion conditioning to odor (Abramson, 1986) and shock (Abramson and Bitterman, 1986). Bees were shown to associate color with odor of food (Couvillon et al., 1991) while Smith et al. (1991) demonstrated proboscis extension conditioning with both aversive and appetitive stimuli. In addition, seed-harvester ants are able to learn a suite of behaviors that enhances foraging efficiency (Johnson, 1991), while cockroaches exhibit probability-learning and habit-reversal (Longo, 1964). Past studies of learning in mantids have dealt with physiological aspects of learning Present address: Department of Biology, University of South Florida, Tampa, Florida 33620