HOSTPLANT CHOICE OF CHECKERSPOT LARVAE: 
EUPHYDRYAS CHALCEDONA, E. COLON, AND HYBRIDS 
(LEPIDOPTERA: NYMPHALIDAE)* 
By M. Deane Bowers 
Museum of Comparative Zoology, Harvard University 
Cambridge, Massachusetts 02138 
Introduction 
Hostplant preference and hostplant utilization abilities may vary 
among species, populations (Scriber, 1983; Blau and Feeny, 1983; 
Singer, 1982, 1983; Holdrenand Ehrlich, 1982; Hsiao, 1978; Ehrlich 
and Murphy, 1981), and individuals (Rausher, 1978; Tabashnik, et 
al., 1981; Wasserman and Futuyma, 1981; Singer, 1982, 1983). 
Although such preferences and utilization abilities may be modified 
by environmental effects such as conditioning (Jermy, et al., 1964; 
Scriber, 1981; 1982; Grabstein and Scriber, 1982), there is clearly 
often an obvious genetic component to the patterns of hostplant use 
observed in nature (e.g., Jaenike and Grimaldi, 1983). The butterfly 
genus Euphydryas (Nymphalidae) is remarkable for the diverse 
strategies of hostplant exploitation exhibited by the six species that 
occur in North America. Euphydryas gilletii, for example, is 
reported to be virtually monophagous on Lonicera involucrata 
(Caprifoliaceae), while E. editha, E. chalcedona, and E. anicia are 
oligophagous, although individual populations may utilize a distinct 
subset of available hosts (Ehrlich, et al., 1975; Ehrlich and Murphy, 
1981; Singer, 1982, 1983). 
In butterflies, as in many other groups of insects, hostplant utili- 
zation is a function of oviposition preference of the female coupled 
with larval adaptation to the host. In the shift to a new hostplant, 
change in adult oviposition preference may occur more quickly than 
larval loss of the ability to utilize ancestral hostplants (Wiklund, 
1975; Scriber and Feeny, 1979; Shapiro and Matsuda, 1980; Singer, 
1982; Scriber, 1983). Thus adult oviposition behavior may not 
always reflect larval preference or fitness on a particular hostplant. 
In a series of elegant experiments with Euphydryas editha, Singer 
* Manuscript received by the editor October 14. 1984 
39 
