Figure 4. Contour graph showing number of flea beetles counted on individual Passiflora vines, as a function of ant presence/absence. Ectatomma species are known to have a strong negative effect on Heliconius caterpillars; however, this data shows a positive relationship with flea beetles. "Other" ants include all other ant species recorded. X= mean number of beetles; N= number of observations. Plants hosting ants in all three ant categories had significantly greater numbers of flea beetles than ant-free plants (p<.0001), and Ectatomma tuberculatum plants had significantly more flea beetles (p<.01) than plants with "other" species of ants. For a list of the common Passiflora-visiting ants at La Selva, see Apple and Feener (2001). The majority of these observations were on Passiflora frequented by flea beetles; this is not a random sample of Passiflora vines.