OVARIAN DYNAMICS IN HELICONIUS BUTTERFLIES - CORRELATIONS AMONG DAILY OVIPOSITION RATES, EGG WEIGHTS, AND QUANTITATIVE ASPECTS OF OOGENESIS

Both oviposition and ovarian morphology were studied in individual butterflies of the neotropical genus Heliconius, which as adults ingest amino acids from pollen, live up to 6 months, and have continuous oögenesis. Among female Heliconius charitonius, daily oviposition correlates directly with the total number of oöcytes developing in the ovaries. The calculated time required for complete growth of one oöcyte is, however, reasonably constant among individuals of a species with widely varying oviposition rates. Thus, within a species, butterflies laying more eggs per day are not necessarily maturing each at a faster rate, but are processing more oöcytes simultaneously in their ovaries. A further correlation between oviposition rate and adult size suggests that in H. charitonius both ovarian capacity and daily egg production are determined ultimately by extent and/or quality of larval nutrition. Among other Heliconius species, those producing larger eggs generally take longer to make them, but also may develop more oöcytes at the same time in their ovaries. Finally, maximal volume attained by the cap of seven nurse cells associated with each growing oöcyte appears constant within a species and among species is directly proportional to average mature egg weight. © 1979.