Jr. Trigo, The chemistry of antipredator defense by secondary compounds in neotropical Lepidoptera: Facts, perspectives and caveats, J BRAZ CHEM, 11(6), 2000, pp. 551-561
Chemical defense against predation in butterflies and moths has been studie
d since nineteenth century. A classical example is that of the larvae of th
e monarch butterfly Danaus plexippus, which feed on leaves of Asclepias cur
assavica (Asclepiadaceae), sequestering cardenolides. The adults are protec
ted against predation by birds. Several other substances may be involved in
chemical defense, such as iridoid glycosides, cyanogenic glycosides, gluco
sinolates, pyrrolizidine and tropane alkaloids, aristolochic acids, glycosi
dase inhibitors and pyrazines. The acquisition of these substances by lepid
opterans can be due to sequestration from larval or adult host plants or de
novo biosynthesis. Many Lepidoptera are known to be unpalatable, including
the butterflies Troidini (Papilionidae), Pierinae (Pieridae), Eurytelinae,
Melitaeinae, Danainae, Ithomiinae, Heliconiinae and Acraeinae (Nymphalidae
), and Arctiidae moths, but knowledge of the chemical substances responsibl
e for property is often scarce. This review discusses mainly three topics:
field and laboratory observations on rejection of butterflies and moths by
predators, correlation between unpalatability and chemicals found in these
insects, and bioassays that test the activity of these chemicals against pr
edators. Perspectives and future directions are suggested for this subject.