February 1st to 5th 2016
Olhão, Portugal
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Shell discoloration in intertidal mussels due to endolithic parasitism: a cool phenotypic shift?

Scientific Exhibition
Biodiversity Effects
Thursday, February 4, 2016 -
17:30 to 19:30

Gandra, M. 1 Zardi, G.I. 2 Nicastro, K.R. 3

1Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
2Dept. of Zoology and Entomology, Rhodes University, 6140 Grahamstown, South Africa
3Centre of Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal

It has long been recognized that parasites play an important role in shaping community structures and determining species' distribution. However, the complex processes by which they impact and regulate host populations are still not completely understood. In intertidal mussels, phototrophic endolithic parasitism has been proven to produce both lethal and sub-lethal effects. Microorganisms such as cyanobacteria actively bore into mussel shells weakening their strength; the demand for shell repair depletes energy resources decreasing byssal attachment strength, which can reduce organisms' capacity to withstand wave action in highly hydrodynamic ecosystems. However, endolith-induced shell erosion is also associated with a change in organisms' phenotype (marked whitening of the shell). Results show that this discoloration can influence the amount of heat absorbed during emersion periods, positively enabling infested individuals to maintain lower body temperatures than non-infested, darker individuals. Using non-invasive infrared technology, we examined mussel cardiac frequencies to assess the physiological response of both infested and non-infested individuals directly exposed to heat stress.
keywords: 
Endoliths, Mytilus galloprovincialis, Bioerosion, Heartbeat, Heat stress

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