The New Neotropical Companion

utilize the plant (such as heliconid caterpillars gaining

evolutionary access to Passiflora). In turn, these insect

herbivores should be under selection pressure to evolve

aposematic coloration. Thus the more aposematic

insects associated with plants, the more likely the plants

are to be biochemically active with regard to potential

drugs. Plant species for the study were chosen from

among 1,380 species. Bioassays of the various species

were tested for activity against various cancers and

parasites. The species tested were taken from six plant

families and were chosen based on consistent activity

or inactivity in bioassays, accessibility in the field, and

abundance in the field. Active (meaning that it had been

determined that medically active compounds were

present in the plant) and inactive plant species were

paired and examined for presence of aposematic insect

species. Twenty plant species (10 active, 10 inactive)

were examined. The results showed that aposematic

insect species were present on both active and non-

active plants but were proportionally more represented

on active plants. The researchers concluded, “The

presence of aposematic insects can therefore indicate

that a particular tropical plant may contain biologically

active compounds. As non- aposematic insects are

more equally associated with active and inactive plants,

using all the insects collected on plants may not be as

informative as using only aposematic insects.” It was

also observed that aposematic insects were common on

plants with non- active compounds, but the possibility

exists that these insects are mimics of other species.

Perhaps future bioprospecting research will begin with

an insect survey.

chapter 11 evolutionary arms races: more coevolution, more complexity 203