Second and third instars were observed from 22 May through 11 June, and fourth and fifth instars from 11 June through 18 June. However, sufficient late-July through September collection records exist to cast doubt upon that supposition. There was no conclusive evidence that a second generation was present during late summer in either 1979 or 1980, although Loftus' sightings of 3 newly-emerged adults on 21 June 1980 was rather late in comparison to all other confirmed 1980 records. In any case, late-emerging adults raises questions concerning the nature of ponceanus diapause and the environmental cues which lead to its onset and termination. Host plant phenology may exert a strong influence on reproductive timing in this butterfly, with natural selection promoting close synchronization of adult emergence and oviposition with maximum production of new foliage by the host plant.
Research is needed to identify any such relationship.
Eggs are oviposited singly on new foliage shortly after adult emergence, with the majority deposited on dorsal leaflet surfaces and a smaller number on leaf rachis. Both egg and larval densities appeared low during 1980. Between 23 April and 25 June, in a sample of 46,483 torchwood leaves on 1,112 plants, only 37 Heraclides eggs were found. H. cresphontes Cramer was also ovipositing, also at apparently low densities, on torchwood leaves at that same time, so some of those observed eggs were probably of that species. Only 2 of the observed ponceanus larvae survived to the fifth instar.