Download or read book Unusual Patterns of Population Genetic Structure Explained by Three New Cases of Poecilogony and Atypical Larval Behavior in Tropical Sea Slugs written by Jessika Lynn M. De Jesus and published by . This book was released on 2018 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: Poecilogony, the production of both feeding (planktotrophic) and non-feeding (lecithotrophic) larvae, occurs in five species of sea slugs in clade Sacoglossa, but only two other animal species. Dispersive planktotrophic sea slugs have little genetic structure across the Caribbean or Indo-Pacific, but non-dispersive lecithotrophic species can be highly structured, with up to 80% of genetic covariance distributed among populations. However, exceptions include over-dispersed lecithotrophs (E. velutinus, E. subornata) and under-dispersed planktotrophs (E. pusilla). Here, we present three new cases of poecilogony: E. velutinus, E. subornata and E. papillosa were exclusively lecithotrophic in oligotrophic central Caribbean waters, but produced 90-100% planktotrophic clutches in higher productivity waters of coastal Panama. Larvae were cultured to metamorphosis in three weeks, and were genetically confirmed as conspecific to lecithotrophic egg-layers. Populations of E. velutinus and E. papillosa from coastal South America had higher genetic diversity and connectivity than in low-productivity sites, indicating local expression of planktotrophy as an explanation for anomalous population-genetic patterns. Conversely, E. pusilla was highly genetically structured across the Indo-Pacific; populations were highly divergent in mitochondrial DNA despite producing primarily planktotrophic larvae. Expression of eyespots at one week and early onset of downward swimming and crawling behavior typical of settling larvae suggest precompetent larvae of E. pusilla avoid advection from natal sites during planktonic development, increasing genetic isolation. Variable development and larval behavior may create unusual patterns of genetic population structure in tropical sea slugs. Quantifying larval behavior can ultimately improve oceanographic models and predictions of larval dispersal and connectivity to aid management and conservation efforts.