Egg Energetics, Fertilization Kinetics, and Population Structure in Echinoids With Facultatively Feeding Larvae

Abstract

Abstract. Larvae of marine invertebrates either arise from small eggs and feed during their development or arise from large eggs that proceed to metamorphosis sustained only from maternal provisioning. Only a few species are known to posses facultatively feeding larvae. Of about 250 echinoid species with known mode of development, only two, Brisaster latifrons and Clypeaster rosaceus, are known to develop through facultatively planktotrophic larvae. To obtain more information on this form of development and its consequences, we determined egg size and egg energetic and protein content of these two species. We found that eggs of B. latifrons resemble those of species with nonfeeding larvae in these characteristics more than those of C. rosaceus. We also compared DNA sequences of the cytochrome oxidase (COI) gene from the Caribbean C. rosaceus to those of the sympatric planktotrophic developer C. subdepressus and also to those of the eastern Pacific species C. europacificus to estimate the degree of divergence between species with different developmental modes. Comparison of COI sequences of C. rosaceus from Panama and Florida revealed that there is no geographic differentiation in this species. Cross-fertilization experiments between C. rosaceus and C. subdepressus indicated that bidirectional gametic incompatibility has evolved between the two species.

Echinoderm Diversity in Panama: 144 Years of Research Across the Isthmus

“…These species have no temporal reproductive isolation, as both have ripe gonads for much of the year, but with peaks from July to October (Lessios 1984). The results of Zigler et al (2008) indicate that the small eggs of C. subdepressus are particularly resistant to fertilization by C. rosaceus sperm, while the larger C. rosaceus eggs are slightly more vulnerable to fertilization by C. subdepressus sperm, but at levels that are unlikely to results in conspecific fertilizations in nature.…”

“…They reported that gamete incompatibility in these species is weaker in sympatry than in allopatry, and based on the mtDNA data in McCartney et al (2000), such gamete incompatibility in these species arose in the last 1.5 million years. Zigler et al (2008) looked at egg energetics, fertilization kinetics, and population structure in echinoids with facultatively feeding larvae. This work included C. rosaceus, one of only two echinoid species known to have facultatively planktotrophic larvae.…”

“…This work included C. rosaceus, one of only two echinoid species known to have facultatively planktotrophic larvae. The eggs of C. rosaceus resemble those of echinoid species with obligately feeding larvae in egg energetic density, egg buoyancy and fertilization kinetics, but resemble non feeding larvae in time to metamorphosis, the early formation of the coelom and the reduced allocation to larval feeding structures (Zigler et al 2008).…”

“…Cross-fertilization experiments between C. rosaceus and C. subdepressus by Zigler et al (2008) revealed that bidirectional gametic incompatibility has evolved between the two species. These species are commonly found together or within close proximity to one another in the shallow waters of the Caribbean in Panama (both species live in the sand, but C. rosaceus is typically more common in turtle grass beds).…”

Desenvolvimento e ciclo reprodutivo da bolacha-do-mar Clypeaster subdepressus (Echinodermata: Echinoidea) de São Sebastião, SP

“…A bolacha-do-mar Clypeaster subdepressus vem sendo utilizada em estudos de desenvolvimento com alguma freqüência (Emlet, 1986;Miner et al, 2005;Reitzel e Heyland, 2007;Smith et al, 2007;Zigler et al, 2008). Emlet (1986) foi o primeiro a mostrar que a espé-cie apresenta desenvolvimento indireto com larva planctotrófica obrigatória.…”