250 
Psyche 
[June 
1 ) What are the advantages of monophagous and polyphagous 
larval feeding habits (c.f. Brues, 1920; 1924; Buxton, 1923; Deth- 
ier, 1954; Brower, 1958; Schoener & Janzen, 1968; Levins & 
MacArthur, 1969) ? 
2) Why do some butterflies exhibit a long-lived adult stage (e.g. 
almost a full year in the Tortoise shell, N ymphalis vau-album ) (c.f. 
Murdoch, 1966; Howe, 1967; Gadgil & Bossert, 1970)? 
3) What selective forces cause the complex voltinism pattern ex- 
hibited by a number of butterfly species in which part of a brood 
becomes dormant while the remainder continues normal development 
(Scudder, 1889; Oliver, 1972)? Perhaps this may allow these spe- 
cies to exploit marginally favorable periods while maintaining a. re- 
serve population for the usually favorable season and/or may aid in 
reducing losses to temporally restricted predators and parasitoids 
(c.f. Baltensweiler, 1968; Waloff, 1968). 
4) Why do some butterflies exhibit multivoltinism ? Perhaps this 
is a means of building up large populations to withstand high mor- 
tality losses in the summer, especially because of biological causes, 
and in the winter, especially because of physical causes, such as is 
seen in several pierid butterflies that start out with low population 
levels in the spring and become more abundant as the summer pro- 
gresses (Scudder, 1889). 
Detailed ecological studies of a taxonomically and geographically 
well-known group like the butterflies will help to answer such ques- 
tions and will aid in making meaningful predictions about such im- 
portant phenomena as the population buildup of a potential or actual 
pest species. 
Acknowledgements 
The author wishes to thank J. Mark Scriber and William Blau 
for reading the manuscript and for their helpful suggestions. 
Literature Cited 
Baltensweiler, W. 
1968. The cyclic population dynamics of the grey larch tortrix, Zeira- 
phera griseana Hubner (=Semasia diniana Guener) (Lepi- 
doptera: Tortricidae) , p. 88-97. In T. R. E. Southwood (Ed.). 
Insect abundance. Symp. Royal Ent. Soc., London #4. Blackwell 
Sci. Publ., Oxford. 
Brower, L. P. 
1958. Bird predation and foodplant specificity in closely related pro- 
cryptic insects. American Nat. 92: 183-187. 
