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Saturniid and Sphingid Caterpillars: Two Ways to Eat Leaves
Author(s) -
Bernays E. A.,
Janzen D. H.
Publication year - 1988
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1941269
Subject(s) - saturniidae , biology , sphingidae , food plant , instar , caterpillar , generalist and specialist species , allometry , frass , insect , host (biology) , vine , arthropod mouthparts , lepidoptera genitalia , ingestion , zoology , botany , ecology , manduca sexta , larva , habitat , biochemistry
We demonstrated allometric differences in relative head mass in different instars of 12 species of Saturniidae and 14 species of Sphingidae. The differences were related to the different ways in which individuals from the two families ate their respective host plants and to the different properties of the hosts that tended to be favored by each lepidopteran family. The saturniids tended to have various simple cutting methods, while the sphingids tore and crushed the food, so that in the former, ingested food was in the form of relatively large uniformly sized pieces, and in the latter it was apparently well masticated. Saturniid mandibles were short and simple, while sphingid mandibles were long, toothed, and ridged in a variety of complex ways. The food of saturniids tended to consist of old, tough, tannin—rich leaves, while that of sphingids was softer, younger, and contained small toxic molecules. The generalists within each group tended to be similar to one another, while the specialists (which occurred more frequently among the sphingids) had very characteristic mandibles, each of unique design. One sphingid species feeding on a vine with characteristically very tough leaves had the "saturniid" design of mandibles. The features typically of the two groups of caterpillar are discussed in relation to feeding strategy, digestion, avoidance of plant "defenses," and rapidity of ingestion.