Author Interview – Predicting diet in brachyuran crabs using external morphology
PeerJ talks to Professor Blaine Griffen from Brigham Young University about “Predicting diet in brachyuran crabs using external morphology“, published in PeerJ Life & Environment as part of the IABO Hub. The IABO Hub is the publishing home of the International Association for Biological Oceanography, and features the latest biological oceanography research published by the members of IABO.
Can you tell us a bit about yourself?
I am a professor of marine biology at Brigham Young University. I study the energetics of marine animals and how they respond to human impacts. Much of my work uses crabs as model organisms, including the work published here.
Can you briefly explain the research you published in PeerJ?
This paper described a method for assessing the relative quality of a crab’s diet based on external markings on its carapace. Crabs have a hard outer skeleton that must be shed and reformed as they grow. With each molt, the soft carapace settles around the internal organs to some extent, leaving marks on the outside of the carapace that outline the main stomach chamber (the cardiac stomach). In our previous work, we have shown that the size of this cardiac stomach increases as crabs include more algae or plant material in their diet. The study published in PeerJ extended that work by examining whether we could use these external markings as a reliable proxy for diet quality in crabs.
What did you discover and where?

Carapace showing external gut markings (black lines) on each of the four species used for intraspecific comparison.
We found that the relative size of the cardiac stomach could be measured quite reliably using these external markings on the carapace, and could therefore provide a simple proxy for crab diet quality without the need to sacrifice the animal or to conduct expensive or time consuming analyses. We examined 50 different crab species and showed that this method works quite well across these species. We also explored whether the same technique could be used to examine intraspecific diet variation; however, our results at this level were not as clear and additional research is needed at the individual level.
What was significant about your findings?
Our findings now provide a method for assessing diet that is free, easy, and nonlethal. This is in contrast to previous methods (stable isotopes, gut content analyses, etc.) that were time consuming, expensive, and often required sacrifice of the animal.
How did you first hear about PeerJ, and what persuaded you to submit to us?
One of the coauthors on the paper recommended that I consider PeerJ.
How was your experience publishing an article in the IABO hub?
It was a very good experience and I was quite pleased with the outcome.
Anything else you would like to add?
Thanks for the opportunity to publish our work.
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