Browsing by Author "Figueira WF"

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    Larval traits show temporally consistent constraints, but are decoupled from postsettlement juvenile growth, in an intertidal fish
    (John Wiley and Sons, Inc on behalf of the British Ecological Society, 8/08/2018) Thia JA; Riginos C; Liggins L; Figueira WF; McGuigan K
    1. Complex life cycles may evolve to dissociate distinct developmental phases in an organism's lifetime. However, genetic or environmental factors may restrict trait independence across life stages, constraining ontogenetic trajectories. Quantifying covariance across life stages and their temporal variability is fundamental in understanding life-history phenotypes and potential distributions and consequences for selection. 2. We studied developmental constraints in an intertidal fish (Bathygobius cocosensis: Gobiidae) with a discrete pelagic larval phase and benthic juvenile phase. We tested whether traits occurring earlier in life affected those expressed later, and whether larval traits were decoupled from postsettlement juvenile traits. Sampling distinct cohorts from three annual breeding seasons afforded tests of temporally variability in trait covariance. 3. From otoliths (fish ear stones), we measured hatch size, larval duration, pelagic growth (larval traits) and early postsettlement growth (juvenile trait) in 124 juvenile B. cocoensis. We used path analyses to model trait relationships with respect to their chronological expression, comparing models among seasons. We also modelled the effect of season and hatch date on each individual trait to quantify their inherent variability. 4. Our path analyses demonstrated a decoupling of larval traits on juvenile growth. Within the larval phase, longer larval durations resulted in greater pelagic growth, and larger size-at-settlement. There was also evidence that larger hatch size might reduce larval durations, but this effect was only marginally significant. Although pelagic and postsettlement growth were decoupled, pelagic growth had postsettlement consequences: individuals with high pelagic growth were among the largest fish at settlement, and remained among the largest early postsettlement. We observed no evidence that trait relationships varied among breeding seasons, but larval duration differed among breeding seasons, and was shorter for larvae hatching later within each season. 5. Overall, we demonstrate mixed support for the expectation that traits in different life stages are independent. While postsettlement growth was decoupled from larval traits, pelagic development had consequences for the size of newly settled juveniles. Temporal consistency in trait covariances implies that genetic and/or environmental factors influencing them were stable over our three-year study. Our work highlights the importance of individual developmental experiences and temporal variability in understanding population distributions of life-history traits.
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    Latitude-wide genetic patterns reveal historical effects and contrasting patterns of turnover and nestedness at the range peripheries of a tropical marine fish
    (Blackwell Publishing Ltd, 1/12/2015) Liggins L; Booth DJ; Figueira WF; Treml EA; Tonk L; Ridgway T; Harris DA; Riginos C
    Few studies have examined core-periphery genetic patterns in tropical marine taxa. The core-periphery hypothesis (CPH) predicts that core populations will have higher genetic diversity and lower genetic differentiation than peripheral populations as a consequence of greater population sizes and population connectivity in the core. However, the applicability of the CPH to many tropical marine taxa may be confounded by their complex population histories and/or high (asymmetric) population connectivity. In this study we investigated genetic patterns (based on mtDNA) across the latitudinal range of the neon damselfish Pomacentrus coelestis (36°N, Japan - 37°S, east Australia). We suggest a novel hypothetical framework for core-periphery genetic patterns and extend typical analyses to include genealogical analyses, partitioned β-diversity measures (total βSOR, turnover βSIM, and nestedness-resultant βSNE), and analyses of nestedness. We found that the existence of two divergent lineages of the neon damselfish led levels of genetic diversity to deviate from CPH expectations. When focusing on the widespread lineage (Pacific clade) nucleotide diversity was higher in the core, supporting the CPH. However, genetic patterns differed toward the northern and southern peripheries of the Pacific clade. The turnover of haplotypes (pairwise-βsim) increased over distance in the north, indicative of historical colonization with little contemporary migration. In contrast, although turnover was still dominant in the south (βSIM), there was no relationship to distance (pairwise-βsim), suggesting the influence of more contemporary processes. Moreover, the haplotype compositions of populations in the south were nested according to latitude, indicating immigration from lower latitudes toward the southern periphery. By extending the typical characterizations of core-periphery genetic patterns we were able to identify the effects of lineage sympatry on measures of genetic diversity and contrasting demographic histories toward the latitudinal peripheries of the neon damselfish's range. Ecography