Contrasting patch choosing by anthophilous ambush predators: vegetation and floral cues for decisions by a crab spider (Misumena vatia) and males and females of an ambush bug (Phymata americana)

Field-collected individuals of Misumena vatia and Phymata americana were compared experimentally as to the kind of vegetation and flower cues they use to choose a hunting site, by introducing them into choice arenas with variously manipulated natural stems of three species of plant and with artificial flowers. Misumena vatia showed a strong preference for stems with flowers or leaves or both; P. americana did not prefer normal stems as strongly and it did not show a statistically significant preference among the various manipulated patches. Both predators discriminated among Solidago canadensis, Daucus carota, and Cirsium arvense, showing a clear preference for the first. Misumena vatia showed a clear preference for yellow artificial flowers on wooden sticks when given a choice of four different colours. Phymata americana preferred yellow or blue to white or red, showing no discrimination between colours of the same group (yellow vs. blue or white vs. red). Misumena vatia took the longest time (ca. 43 min) to complete its choice of stem; female and male P. americana took 18 and 15 min, respectively. In all the experiments P. americana showed sexual diethism, the females being more choosy than the males. The ranking of discrimination from greatest to least was as follows: M. vatia, females of P. americana, and males of P. americana. We suggest that both species of predators have different strategies of patch choice and that in the case of P. americana, males and females have different patterns of patch selection, the males searching not only for prey but also for mates.