Meeting Abstract

80.4  Tuesday, Jan. 6  Consistent behavioral and life history variation within clones of the killifish Kryptolebias marmoratus EARLEY, RL*; CAMPBELL, JM; HSU, Y; University of Alabama; California State University Fresno; National Taiwan Normal University rlearley@bama.ua.edu

For decades, a popular debate has raged regarding the relative contributions of genetic inheritance and environment to phenotypic variation. Some invertebrate/plant systems have provided insights into this question but there are far fewer vertebrates in which the impact of the environment on complex social behaviors can be investigated independent of genetic variation. The mangrove killifish, Kryptolebias marmoratus is a unique exception because it exists naturally as a self-fertilizing simultaneous hermaphrodite and, in many cases, completely homozygous parents produce offspring genetically identical to themselves. We examined variation in life history traits, aggressive behavior, and endocrine profiles both within and among six killifish clones. We also determined whether individuals exhibit consistent behavioral and endocrine variation over a time span of up to one year. Individual killifish showed highly repeatable aggressive responses to mirror image stimulation, and significant consistency in pre- and post-fight androgen (but not corticosteroid) concentrations. Further, there was significant variation in aggressive and endocrine responsiveness among individuals within a clone and among clones. We also found that suites of life history traits (e.g., time of maturation, fecundity) covary with one another, and with both behavior and endocrine measures. These covariation patterns suggest that some clones invest considerably in competition while others invest heavily in reproduction. We interpret our preliminary findings as indicative that the environment might play a central role in mediating phenotypic variation in the killifish. In addition, these initial results will serve as a springboard for more rigorous experimental approaches to the question of what governs the phenotype in this novel organism.