SEXUAL STRATEGIES IN PLANTS. II. DATA ON THE TEMPORAL REGULATION OF MATERNAL INVESTMENT

Seventeen angiosperm species were examined to determine the degree to which the plants of each sexual morph limit their maternal investment during one reproductive session at three successive floral stages (flower determination, pre-anthesis ovary development, and postanthesis fruit maturation). The results indicate that species and sexual morphs differ dramatically in the relative use they make of the three stages. Both the flower number per inflorescence and the proportion of flowers with developed ovaries are generally less variable in species with inflorescences which have well defined sequences of flower development. In most species, the variability among the plants of one morph is greater in the frequency of fruit maturation than in the frequency of ovary development. Much of the intra-morph variation in both the frequency of ovary development and the frequency of fruit maturation appears to be non-genetic. In most of the morphs examined, the frequencies of ovary development and fruit maturation are not correlated with the number of flowers per plant or with each other. The results provide circumstantial evidence in support of the hypothesis of serial adjustment of maternal investment.