Distances at which jumping spiders (Araneae : Salticidae) distinguish between prey and conspecific rivals

Distances at which jumping spiders (Salticidae) use optical cues to disting uish between prey insects and conspecific rivals were investigated using ad ult males of 37 species. During tests, salticids walked up a ramp toward a mirror or toward an insect enclosed in a transparent petri dish. All specie s directed threat displays toward their own mirror images and the displays were comparable to each species' typical behaviour during male-male interac tions. The salticids never displayed in tests with insects at the top of th e ramp. The virtual distances at which the spiders displayed are interprete d as an indication of the distances at which each species can distinguish r ivals from prey. Representative species were from the subfamilies Lyssomani nae, Spartaeinae and Salticinae. Discrimination distances relate well to th e foveal layer I receptor mosaics of the anterior median eyes for the three subfamilies. Compared with the salticines, the lyssomanines and, except fo r Portia, the spartaeines tended to have shorter discrimination distances. Portia spp. had discrimination distances comparable to the longest recorded for the salticines. The longest discrimination distances found were for th e salticine Mogrus neglectus (max. 320 mm or 42 body lengths) and for the s partaeine Portia fimbriata (280 mm or 47 body lengths).