1972] 
Young — Dismorphia virgo 
175 
and Raven, 1965; Fraenkel, 1959), the major larval host plant fam- 
ily of these butterflies. The biology of O. zelica pagasa will be sum- 
marized later (Young, in prep.)* 
The possible position of I. caesia tenuicornis in a mimicry com- 
plex at Cuesta Angel (Table 2) is less clear at this time. It is 
far more abundant locally than either D. virgo or O. zelica pagasa 
(Table 2) during July and August. Three possibilities exist here: 
( 1 ) /. caesia tenuicornis is unpalatable and bears Mullerian mimetic 
relation with O. zelica and perhaps Batesian relation to D. virgo , 
(2) /. caesia tenuicornis is palatable, at certain times of the year it 
is unusually abundant, and mimetic association, if any, breaks down. 
(Under the alternative, at other times of the year its local abun- 
dance does not exceed that of O. zelica pagasa and it is a Batesian 
mimic of that butterfly during those times.) and (3) I. caesia tenui- 
cornis does not enter into a mimicry complex at Cuesta Angel at any 
time of the year. The weaker resemblance of this species to either 
of the other butterflies suggests that this may be the case, although 
more extensive field study is needed to confirm any of these alterna- 
tive ideas. The major larval host plant of L caesia tenuicornis at 
Cuesta Angel during July and August is Gynandropsis pulcherrima 
in the Capparidaceae (Young, in prep.), a plant family rich in mus- 
tard oil glucosides (Alston and Turner, 1963). Since experimental 
feeding studies were not conducted, the palatability of I. caesia tenu- 
icornis remains undetermined. 
A final interesting point is the increased rate of development of 
D. virgo on young leaves of I. pittieri (Table 1). In this presum- 
ably palatable butterfly, natural selection should favor oviposition on 
young leaves of the host plant since such behavior on the part of the 
female butterfly would reduce the risk of predation or parasitism on 
the larvae (since less time is spent in the larval stage when larvae 
eat young leaves). But the extent to which this adaptive mechanism 
is operative in populations of D. virgo or any palatable species de- 
pends upon the seasonal pattern of vegetative growth in the host 
plant population at a given locality. It is then hypothesized the rates 
of predation or parasitism will vary seasonally, and that such tem- 
poral differences are partly accountable through the pattern of leaf- 
ing out (vegetative growth). Thus it is predicted that the local 
abundance of D. virgo depends upon the time of year and perhaps 
upon the type of plant community (i.e., shaded understory versus 
well insolated clearings and marginal habitats) since a plant spe- 
cies may show different physiological responses (associated with 
growth and maintenance) in different communities (Holdridge et 
