Effects of habitat variation on life history traits and genetic structure of Bartholomea annulata on Caribbean coral reefs

Abstract

Phenotypically plastic life history strategies have important implications for how species colonize local habitats and disperse to distant environments, yet few data exist for tropical sea anemones. Here, I use field and laboratory experiments, coupled with molecular analyses, to determine how habitat heterogeneity influences the life history strategies of the corkscrew sea anemone Bartholomea annulata on Caribbean coral reefs. Current habitat, rather than site of origin, appears to drive patterns of growth and recruitment in natural populations, while lifespan may be controlled by genetically induced senescence (Chapter 2). Food availability influences growth and reproductive strategies, in that regularly fed individuals grow more rapidly but pedal lacerate less than do starved individuals (Chapter 3). Molecular analyses of natural aggregations of B. annulata indicate that clonal proliferation occurs in the field, but is uncommon and plays a minor role in the genetic structure of these populations (Chapter 4). I conclude that B. annulata exhibits phenotypically plastic growth and reproduction, but not lifespan, and that variation in these life history strategies is driven in part by current environmental conditions.