1 research outputs found
Settlement induction of Acropora palmata planulae by a GLW-amide neuropeptide
11 páginas, 5 figuras, 1 tabla.Complex environmental cues dictate the settlement of coral planulae in situ; however, simple artificial
cues may be all that is required to induce settlement of ex
situ larval cultures for reef re-seeding and restoration
projects. Neuropeptides that transmit settlement signals and
initiate the metamorphic cascade have been isolated from
hydrozoan taxa and shown to induce metamorphosis of
reef-building Acropora spp. in the Indo-Pacific, providing a
reliable and efficient settlement cue. Here, the metamorphic activity of six GLW-amide cnidarian neuropeptides
was tested on larvae of the Caribbean corals Acropora
palmata, Montastraea faveolata and Favia fragum.
A. palmata planulae were induced to settle by the exogenous
application of the neuropeptide Hym-248 (concentrations
C1 9 10
-6
M), achieving 40–80% attachment and 100%
metamorphosis of competent planulae (C6 days post-fertilization) during two spawning seasons; the remaining
neuropeptides exhibited no activity. Hym-248 exposure
rapidly altered larval swimming behavior (\1 h) and
resulted in [96% metamorphosis after 6 h. In contrast,
M. faveolata and F. fragum planulae did not respond to any
GLW-amides tested, suggesting a high specificity of neuropeptide activators on lower taxonomic scales in corals.
Subsequent experiments for A. palmata revealed that (1)
the presence of a biofilm did not enhance attachment effi-
ciency when coupled with Hym-248 treatment, (2) neuropeptide-induced settlement had no negative effects on early
life-history developmental processes: zooxanthellae
acquisition and skeletal secretion occurred within 12 days,
colonial growth occurred within 36 days, and (3) Hym-248
solutions maintained metamorphic activity following storage at room temperature (10 days), indicating its utility in
remote field settings. These results corroborate previous
studies on Indo-Pacific Acropora spp. and extend the
known metamorphic activity of Hym-248 to Caribbean
acroporids. Hym-248 allows for directed and reliable settlement of larval cultures and has broad applications to the
study and rehabilitation of threatened Acropora populations in the Caribbean.Funding was provided by the UNCW MARBIONC Business of Marine Biotechnology Program and the World Bank/GEF
funded Coral Reef Targeted Research Program, Connectivity Working Group awarded to AMS.Peer reviewe