Biol. Bull. Sign up for etocs!
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Sewell, M. A.
Right arrow Articles by Young, C. M.
Right arrow Search for Related Content
PubMed
Right arrow Articles by Sewell, M. A.
Right arrow Articles by Young, C. M.

The Biological Bulletin, Vol 193, Issue 3 297-305, Copyright © 1997 by Marine Biological Laboratory

RESEARCH NOTE

Are Echinoderm Egg Size Distributions Bimodal?

M. A. Sewell and C. M. Young
Department of Larval Ecology, Harbor Branch Oceanographic Institution, 5600 U.S. 1 North, Fort Pierce, Florida 34946

Marine invertebrates can be categorized into species that reproduce by producing either large numbers of small, energetically inexpensive eggs that become planktotrophic larvae, or fewer, larger eggs with more yolk and lecithotrophic development (1). The selective advantages of these alternative strategies were considered in a series of simple mathematical models by Vance (2, 3). These models predicted that intermediate egg sizes should have lower reproductive efficiency, and that only extreme egg sizes should be evolutionarily stable (2, 3). Specifytally, Vance's models (2, 3) and later modifications (4-7), predict that eggs of marine invertebrates should have bimodal size distributions, rejecting the contrast between small egg/feeding and large egg/nonfeeding modes of development and the selection against intermediate egg sizes. Evidence for bimodality in egg size distributions is, however, equivocal, with unimodal distributions seen in the majority of comparative studies that are appropriate tests of the hypothesis (8-13). Bimodal distributions have been described only in a few groups of molluscs (4) and asteroid and echinoid echinoderms (14). Here we test the prediction of bimodality in the holothuroid and ophiuroid echinoderms and show that although the natural log-transformed egg size distributions are visually unimodal, the holothurian egg size distribution is statistically composed of two discrete modes. Moreover, reexamination of the asteroid and echinoid egg size distributions (14) with the addition of data from more recent literature confirms that there are two statistical modes in the egg size distributions of these classes. Thus, in the phylum Echinodermata, there is a bimodal egg size distribution three of the four classes in which this prediction can tested.


This article has been cited by other articles:


Home page
 Biol. Bull.Home page
D. J. Marshall and T. F. Bolton
Effects of Egg Size on the Development Time of Non-feeding Larvae
Biol. Bull., February 1, 2007; 212(1): 6 - 11.
[Full Text] [PDF]

Home page
 Biol. Bull.Home page
I. Falkner, M. Byrne, and M. A. Sewell
Maternal Provisioning in Ophionereis fasciata and O. schayeri: Brittle Stars With Contrasting Modes of Development
Biol. Bull., December 1, 2006; 211(3): 204 - 207.
[Abstract] [Full Text] [PDF]

Home page
 Integr. Comp. Biol.Home page
L. A. Levin
Recent progress in understanding larval dispersal: new directions and digressions
Integr. Comp. Biol., June 1, 2006; 46(3): 282 - 297.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1997 by the Marine Biological Laboratory.