Alternative life histories of the genusLucania: 3. An ecomorphological explanation of altricial (L. parva) and precocial (L. goodei) species

Abstract

SynopsisImportant differences were observed in the early ontogenies of Lucania parva and Lucania goodei. These differences can be explained in terms of the altricial-precocial model of speciation. Lucania parva can be recognized as an altricial form that produces many eggs with relatively little yolk investment, compared to the more precocial L. goodei. Many of the differences observed in embryo, larva and juvenile specimens appear to be related to these differences in gamete investment. Accelerated developmental rates in the precocial form suggest that paedomorphosis is an important proximate mechanism in the bifurcation of alternative lifehistory styles in this genus. Some morphological characteristics, such as vitelline circulation and body shape, may be transformations associated with the particular environmental conditions in which the animals must develop and survive. Our observations suggest that these two species in the genus Lucania have followed different ontogenic trajectories in response to prevailing environmental conditions.