Caleb C. Butler
(he/they)
LaJeunesse LaB PHD Candidate
Hello! I am a marine ecologist at the Pennsylvania State University working on coral-algal symbiosis. Here, I am interested in the ecology and evolution of coral symbionts in family Symbiodiniaceae. We define coral bleaching by the loss of these symbionts, and yet, we still know very little about their taxonomy, physiology, and why and when they choose to associate with specific corals over others. My research aims to investigate these questions while addressing better ways for us to communicate and address these organisms.
My identity
Hello! My name is Caleb C. Butler. Currently, I am a NSF graduate research fellow and am a fifth year Ph.D. candidate in the LaJeunesse Lab at the Pennsylvania State University. While my research predominantly focuses on Symbiodiniaceae and how they interact with their many hosts, my interests extend broadly into all forms of symbiosis and how specificity evolves and changes across different environments and organisms.
Prior to entering my doctoral program, I attended the University of Texas at Arlington where I completed B.S. degrees in Biology and Microbiology with a Biochemistry minor. There, I worked with Dr. Lauren Fuess in Dr. Laura Mydlarz’s Coral Immunity Lab, focusing on better understand the innate immunity of reef-building corals in the Caribbean.
I identify as a non-binary individual with he/they pronouns. This means I am comfortable with either pronoun and am also fine with them being used interchangeably, and further, identify as a member of the LGBTQ+ community.
While the future is uncertain, I am always interested in collaborating on projects to better understand the ecology and evolution of these symbiotic (or free-living!) dinoflagellates. From Sanger Sequencing to large scale omics, there are countless questions we still have yet to answer about these fascinating organisms. If you are interested in talking further, feel free to contact me at ccb5308@psu.edu or DM me on Twitter.
My Research
FAmily Symbiodiniaceae
Symbiodiniaceae are single-celled photosynthetic algae also known as dinoflagellates. Many of these organisms have evolved highly specific mutualisms with all forms of corals, sea anemones, jellyfish, and more! Symbiodiniaceae comprise many genera with hundreds to thousands of putative species — but with only a handful of described species. Thus one of my main missions, while conducting critical research on the ecology of these organisms, is to formally describe species we have yet to put a name to.
What is a species?
When we talk about species as taxonomists, we are talking about a hypothesis that categorizes one specific group from a whole. While many species concepts have come about through the years, as a hypothesis, we combine multiple lines of evidence to support the idea that one group is a species.
Why do we care about species?
Defining a species allow us to better communicate and aggregate information on these organisms, because not all Symbiodiniaceae are equal! While some may associate with two to three species of coral in one environment, another species may be able to associate with upwards of fifteen different families of reef building corals across the whole Indo-Pacific Ocean. That’s a big disparity! These differences matter to coral-algal biologists as different species create different symbioses.
2023 - Indo-Pacific Generalists
While many Symbiodiniaceae are highly specific to a small range of host and environments (especially in the Atlantic Ocean), the Indo-Pacific Ocean hosts a few generalist symbionts that can associate with a wide range of different host organisms and live in many different environments. Here we describe five new species in the genus Cladocopium, all of which can be found in hot spots of coral reef research. Many coral researchers in the past, present, or future will likely work with one or more of these symbionts. With proper species description, we can be cognizant of these organisms and how their unique attributes affect their host corals. Read more.
2022 - coexisting in a jellyfish
Most reef building corals only associate with one dominant symbiont at a time, but in a jellyfish found in the Mediterranean, Cotylorhiza tuberculata, this is not the case. In fact, two species of Symbiodiniaceae across two different genera are able to co-exist within this organism simultaneously. In this unusual case, we use a combination of molecular techniques to verify the co-existence of these organisms, while cautioning other researchers on the over-interpretation of genetic markers with multiple copies in a singular organisms. Read more.