Tuesday, November 13, 2012

Congratulations Kecia!


Today is a big day for the CollinLab. 

Kecia Kerr, the first PhD student from the CollinLab successfully defended her dissertation.  After 5 years of hard work and intensive questioning on her research, Kecia will be awarded a PhD from the NEO Program at McGill University.   It’s a great accomplishment and her project has produced some cool results.

Working with fiddler crabs, Kecia focused on how changes in temperature influence the timing of reproduction.  These crabs are good mothers and after brooding their eggs, they time hatching to occur when predation risk is lowest for the hatching larvae.  In most places around the world female crabs release their tiny larvae at night on the days with the biggest tides. We think this is because predatory fish can’t see the larvae very well at night.  And, that during large tides the water sucks the larvae offshore to safer areas; away from predators that are more common in the shallow water.

Climate change is expected to alter the seasonal upwelling of cold water that normally happens between January and May here in Panama.  It is likely that the intensity and also the frequency of these events will increase.  Kecia wanted to know if the crabs will be able to adjust to the more variable temperatures we expect to have in the future.



Changes in temperature can alter the rate of development.  So how can the crabs ensure that their larvae hatch at the right time?  Kecia found that different species do different things.  One species can predict the temperatures that they will experience while they brood.  They use their experience of current temperatures to adjust when they mate and lay their eggs.  Females of the other species are not flexible in when they mate or lay eggs.  Instead these crabs can adjust the temperature experienced by their eggs:  The females move up and down in their burrows finding the right temperatures to keep their eggs on track to hatch on time.

Even with these strategies the crabs sometimes make errors and release their larvae on the wrong days.  How these errors effect the survival of the crabs is a question Kecia hopes to answer in the future.

Kecia’s first dissertation chapter is already published.  You can read it in Marine Ecology Progress Series here:  http://www.int-res.com/articles/feature/m459p001.pdf

Watch these videos to get an idea of what Kecia’s fieldwork is like.



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