Differential host use affects fecundity of the gastropod Crepidula onyx

作者：Von Tungeln Amber R; Pernet Bruno^*

来源：Marine Ecology-An Evolutionary Perspective, 2017, 38(2): UNSP e12421.

DOI：10.1111/maec.12421

• Calyptraeidae
• fitness
• host choice

For epibiotic or symbiotic marine invertebrates, alternative host species may differ substantially in quality, and under some circumstances such differences in host quality may lead to the evolution of increased host specificity. However, the fitness consequences of alternative hosts for epibiotic or symbiotic marine invertebrates have rarely been quantified. In Southern California, the gastropod Crepidula onyx is often found as an epibiont on either bay mussels (Mytilus galloprovincialis) or cone snails (Conus californicus). These hosts differ greatly in maximum size, with possible effects on size at sex change and final size in Cr.onyx, and thus on fecundity. Further, Cr.onyx on the two hosts differ in shell shape, possibly affecting the size of the ctenidium, which Cr.onyx uses for suspension feeding. We examined these potential effects of host use on fitness components in Cr.onyx. Epibionts on mussels reached much larger average sizes than did those on cone snails; further, epibionts on mussels often completed sex change at much larger sizes than did those on cone snails. On average, mussel epibionts had threefold higher average fecundities than did cone snail epibionts. Although there was a slight difference in shell shape between epibionts on the two host species, there was no difference in the scaling of ctenidium area with body size for Cr.onyx from the two hosts. The large average differences in fecundity in epibionts associated with the two alternative hosts suggests that there may be strong selection on host choice at larval settlement.

• 出版日期2017-4