Smith JG and Garcia SC (2021), Variation in purple sea urchin (Strongylocentro...

ECB-ART-49181

PeerJ 2021 Apr 06;9:e11352. doi: 10.7717/peerj.11352.

Show Gene links Show Anatomy links

Variation in purple sea urchin (Strongylocentrotus purpuratus) morphological traits in relation to resource availability.

Smith JG , Garcia SC .

???displayArticle.abstract???
Flexible resource investment is a risk sensitive reproductive strategy where individuals trade resources spent on reproduction for basic metabolic maintenance and survival. This study examined morphological variation in herbivorous sea urchin grazers across a mosaic landscape of macroalgae dominated habitats interspersed with patches of sea urchin barrens to determine whether sea urchins shift energy allocation in response to food limitation. Extensive underwater surveys of habitat attributes (e.g., sea urchin density, algae cover) were paired with detailed laboratory assays (e.g., sea urchin dissections) to determine how resource abundance affects energy allocation between reproductive capacity and body structure in the purple sea urchin, Strongylocentrotus purpuratus. We found that: (1) sea urchins had a more elongate jaw structure relative to body size in habitats void of macroalgae (i.e., barrens), (2) sea urchin reproductive capacity (i.e., gonad index) was lower in barrens and the barrens habitat was primarily comprised of encrusting algae, and (3) sea urchin jaw morphology (i.e., lantern index) and reproductive capacity (i.e., gonad index) were inversely related. These results suggest that sea urchins respond to macroalgae limited environments by shifting energy allocation between reproductive capacity and modifications of the foraging apparatus, which may explain the ability of sea urchins to acquire food in resource-limited environments.

???displayArticle.pubmedLink??? 33987021
???displayArticle.pmcLink??? PMC8086578
???displayArticle.link??? PeerJ

???attribute.lit??? ???displayArticles.show???

References [+] :

Guillou, The effect of feeding or starvation on resource allocation to body components during the reproductive cycle of the sea urchin Sphaerechinus granularis (Lamarck). 2000, Pubmed, Echinobase

	Figure 1. Subtidal survey sites along the Monterey Peninsula, California, USA.Brown squares indicate kelp forests and purple triangles indicate sea urchin barrens.
	Figure 2. Sea urchin shape and structure.Sea urchin shape and body structure with (A) lantern length (mm) plotted against lantern width (mm), and (B) test height (mm) plotted against test diameter (mm). Linear regressions lines are shown for barrens (purple) and forests (green) and shaded with the 95% confidence intervals surrounding each mean.
	Figure 3. Lantern length and gonad weight between habitat types.Log-transformed lantern length (A) and gonad weight (B) between kelp forests (green) and sea urchin barrens (purple) with log-transformed test diameter as a covariate. Shaded regions depict the 95% confidence of fit surrounding each regression line.
	Figure 4. Lantern index and gonad index as functions of the percent cover of algae.Lantern index (A, C, E) and gonad index (B, D, F) as a function of the percent cover of encrusting (A, B), brown (C, D), and foliose red (E, F) algae. Each point depicts the mean cover of algae within a given site. Shaded regions indicate the 95% confidence of fit surrounding each linear regression line.
	Figure 5. Beta regression probability density functions for proportion of algae cover as a function of mean purple urchin density.