Meeting Abstract
P2.55 Sunday, Jan. 5 15:30 Heritability of fitness-related traits in populations of Porites astreoides from different thermal environments KENKEL, CD*; MATZ, MV; The University of Texas at Austin; The University of Texas at Austin carly.kenkel@gmail.com
Determining the amount of genetic variability in traits under selection is essential for evaluating a population’s potential for evolutionary change. However, additive genetic variation is sensitive to environmental condition and evolutionary predictions can be improved by understanding such effects. Predicting response to selection is particularly important for reef-building corals, which experience substantial environmental variation across species ranges and are undergoing climate change at an unprecedented rate. We evaluated variation in growth rate and survival in 38 families of recruits of the coral Porites astreoides obtained by settling larvae released by parent colonies originating from two different populations. Recruits were reared in common garden conditions for 5 weeks and then subjected to two thermal treatments (28°C and 31°C) for 2.5 weeks. Survival and growth were measured both pre and post thermal treatment for recruits and fragments of the parental colonies. The most significant parental effects were detected during the first 5 weeks: 95% of variance in survival and 42% of variance in growth rate of surviving recruits were explained by parental genotype. In the post-treatment measures these effects diminished such that only 16% of variance in growth rate was explained by parental genotype, of which 3% was attributable to parent origin (inshore or offshore). Still, juvenile growth rate remained positively correlated with parental growth rates. Unexpectedly, heat treatment did not result in any additional variance in recruit growth despite having a significant negative effect on parental growth. This result suggests that thermal stress does not affect fitness in juvenile P. astreoides, which may underpin the contemporary demographic success of this coral species.
