abstract
Corbicula fluminea, is one of the most successful invasive species in fresh and brackish waters. Dispersal is one of the most determinant steps in the invasive process, and the full understanding of the mechanisms involved in this step is critical for adequate pest management both in the wild and in industries affected by this species' biofouling activity. A mucous drogue line produced by mucocytes packed along the inner demibranchs of the clams' gills seem to play an important role in assisting drifting and hence dispersal. Two Asian clam populations geographically separated (one in the USA and the other in Portugal), investigated at different times of the year, were reported to differ in terms of mucous drogue line production and floating. In this study, genetics and seasonality effects were hypothesized to explain the difference between the populations. To test these hypotheses, the two populations were genetically compared, and the Portuguese one was followed for 14 months to record the animals' mucous drogue line production and flotation capabilities and locate the population reproductive periods. Our results signal a possible scenario of micro-evolution with consequences on the production of the clams' mucilaginous drogue line. Although some authors advocate a link between mucous threads formation and reproduction events, such a relationship was not observed in this study. By contributing to the understanding of a physiological trait of the Asian clam that is important for dispersal, this study may be of practical relevance for pest monitoring and control.
keywords
DE-LA-PLATA; POPULATION-DYNAMICS; ASIATIC CLAM; LIFE-CYCLE; NATURAL-POPULATION; RIVER RHINE; BIVALVIA; MULLER; ESTUARY; FRANCE
subject category
Marine & Freshwater Biology
authors
Rosa, IC; Pereira, JL; Costa, R; Gomes, J; Pereira, MD; Goncalves, F
our authors
Inês Correia Rosa
Science and Technology Manager
Maria de Lourdes Gomes Pereira
Associate Professor with Aggregationacknowledgements
The authors are grateful to Joao Simoes, Carolina Madeira and Artur Alves for their advice regarding genetic analysis, as well as to Robert Prezant for his help in interpreting histological results. Bruno Castro, Henrique Queiroga and Alexandre Caseiro provided important guidance on the analysis of the population data. We would also like to thank all colleagues who helped in the field work as well as Rebecca Shell for collecting the clams from the USA population used in the genetic analysis. Ines Correia Rosa and Joana Luisa Pereira are recipients of individual scholarships by the Portuguese Foundation for Science and Technology (FCT) (Ph.D. scholarship SFRH/BD/33395/2008 and Post-Doctoral scholarship SFRH/BPD/44733/2008, respectively). This study was supported by the European Regional Development Fund - EDRF, through the Operational Competitiveness Programme - COMPETE, and by national funds through FCT under the scope of the project PTDC/AAC-AMB/113515/2009,CICECO - PEst - C/CTM/LA0011/2013 is acknowledged.