The crown-of-thorns sea star Acanthaster planci is a key predator of corals and has had a major influence on the decrease in coral cover across the Indo-Pacific. To understand how this species may adapt to ocean warming and acidification, this study used a quantitative genetic approach to examine the response in offspring of 24 half-sib A. planci families raised in fully crossed treatment combinations of temperature (27, 29 and 31 °C) and pCO2 (450 and 900 ppm) to the gastrulation stage (26 h post-fertilisation). Interactions between genotype and environment were tested using a permutational multivariate ANOVA and restricted error maximum likelihood calculations of variance. High temperature (31 °C) significantly reduced normal (symmetrical, intact) development by ~15% at the 16-cell stage. Increased temperature (from 29 to 31 °C) reduced normal gastrulation from ~65 to ~30%. The extent to which each genotype was affected depended on sire identity, which explained 15% of variation. pCO2 did not significantly influence development at gastrulation. To explore the importance of individual mating pairs, response ratios were calculated for offspring of each family across all treatments. Response ratios demonstrated that the majority of genotypes experienced the highest percentage of normal development to gastrulation in the control treatment, and that family (sire × dam) is important in determining the response to ocean warming and acidification. A positive genetic correlation (overall r*G = 0.76) from sire × environment interactions, however, indicated that individuals which develop ‘better’ at both high temperature and high pCO2 may cope better with near-future predicted warm and acidified conditions for eastern Australia.
Sparks K. M., Foo S. A., Uthicke S., Byrne M. & Lamare M., 2017. Paternal identity influences response of Acanthaster planci embryos to ocean acidification and warming. Coral Reefs 36:325. Article (subscription required).