Ls. Fink, FOODPLANT EFFECTS ON COLOR MORPHS OF EUMORPHA-FASCIATA CATERPILLARS (LEPIDOPTERA, SPHINGIDAE), Biological Journal of the Linnean Society, 56(3), 1995, pp. 423-437
Caterpillars of the hawkmoth Eumorpha fasciata are highly polymorphic
for colour, with green, pink, and pink-and-yellow forms in the second
through fourth instars, and green and multicoloured forms in the fifth
instar. Four years of field censuses on four foodplant species determ
ined that all morphs were found on all plant species; morph frequencie
s were homogeneous on each plant species over time; and morph frequenc
ies differed consistently among plant species. When larvae were reared
from eggs on three of the hostplant species in the laboratory, differ
ences in morph frequencies paralleled the census results. Thus foodpla
nt quality is one factor affecting larval colour in E. fasciata. A lit
erature survey reveals that foodplant effects on larval colouration ma
y be widespread in the family Sphingidae, but most reports are anecdot
al rather than experimental. The implications of this mechanism of col
our determination are discussed.