1973] 
Young — Parides areas mylotes 
15 
functional and brightly-colored defensive organ, the osmeterium, and 
(3) probably the possession of generally toxic or poisonous systemic 
properties making the insect unpalatable, since they feed on vines 
reputed to have very toxic properties. 
Discussion 
Young (1971a) reported a developmental time for Battus poly- 
damus on Aristolochia veraguensis of about 14 days under similar 
laboratory conditions to those employed in the present study. Straat- 
man (1971) reported the developmental time of Ornithoptera alex- 
andrae Rothschild to be 13 1 days on Aristolochia schlechteri and 
107 days on A. tagala, where the difference occurred during the 
larval period. The developmental time of Parides areas mylotes on 
Aristolochia sp. from La Selva is 42 days (Young, 1972a) while 
53 days on A. constricta (Table 1.). Furthermore, the develop- 
mental time of Parides childrenae on Aristolochia pilosa at La Selva 
is about 42 days (Young, 1972a). Thus different genera in the 
Troidini have different developmental times on different species of 
Aristolochia. At La Selva there has been ecological divergence be- 
tween P. areas mylotes and P. childrenae with respect to the species 
of Aristolochia used for oviposition and larval food-consumption. 
Furthermore, two different strains of P. areas mylotes are evolving 
between La Selva and Tirimbina: the duration of all immature life 
cycle stages has been altered and the species feeds on a different 
species of Aristolochia at each locality. If this difference in develop- 
mental time was due solely to differences between the larval food 
plant species, we would expect to find only a change in duration of 
the larval period similar to that noted by Straatman (1971) in 
Ornithoptera alexandrae on New Guinea. But in the case of P. 
areas mylotes, there has been a change in the embryonic and post- 
embryonic developmental time which suggests genetic alterations. 
Strain-effect is not solely confined to food plant differences of the 
type noted for Victorina epaphus on the Pacific and Caribbean slopes 
of the central Cordillera in Costa Rica (Young, 1972c). Precisely 
what sorts of ecological factors are reshaping the developmental 
architecture of P. areas mylotes at different localities on the Carib- 
bean drainage of the central Cordillera in Costa Rica remain obscure 
at this time. One interesting hypothesis concerning this question 
would focus on a higher level of predation pressure on eggs and 
larvae in La Selva populations of the butterfly, which would favor 
an accelerated developmental period for these life stages. 
