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Santa Cruz, CA

Vikram Baliga, PhD Candidate at UC Santa Cruz, member of the Mehta Lab. Areas of study: ecology, ontogeny, morphometrics, and comparative methods.


Integrating MorphologY, Phylogeny, and OntogenY to Understand Ecology

A bluestreak cleaner wrasse (Labroides dimidiatus) cleaning a French grunt (Haemulon flavolineatum)

I strive to be an "integrative" biologist. I've long been intrigued by the diversity we see in nature, in part because of the sheer complexity that it provides. I strongly believe in incorporating as much information from diverse sources as we can to unravel the complexity of biological systems.

One such complex system is the evolution of cleaning behavior in fishes. Cleaner fishes are species that pick ectoparasites off other organisms. The evolution of cleaning is particularly notable as it represents one of the few examples of mutualisms among vertebrates.

Over 120 species of marine fishes across 18 families engage in this behavior. Curiously, the majority of these species (over two-thirds) clean predominately as juveniles, transitioning to other dietary strategies upon reaching adulthood. Figuring out why certain species clean as juveniles while others do not has been a focal point in my dissertation research. 

I use the evolution of cleaning behavior as a model system to see how incorporating phylogenetic and ontogenetic information informs our understanding of ecological patterns.

Still image from a high-speed video of Labroides dimidiatus inspecting a suspended (euthanized) client fish. This cleaner can feed upside down!

To explore these patterns, I have focused chiefly on the evolution of cleaning behavior in the Labridae (wrasses & parrotfishes). This group holds the largest diversity of cleaner fishes in a family, with at least 58 species exhibiting this behavior.

Nearly all cleaners in the genus Thalassoma clean predominately as juveniles. In a case study, I discovered that Thalassoma cleaner wrasses, as juveniles, possess jaws with low mobility and exhibit low bite forces compared to non-cleaner congeners (Baliga and Mehta, 2014). Upon reaching adulthood, however, morphological and functional differences between cleaners and non-cleaners begin to blur. The sizes at which I first found overlap between cleaner and non-cleaner species in feeding traits approximately correspond with the body lengths around which these species shift from juvenile to adult coloration patterns. Thus, a large suite of ontogenetic change accompanies the dietary shift in these species.

Next, I used high-speed videography to record and analyze the feeding behaviors of juveniles in three species of cleaner wrasses. I recently published some of my findings in Journal of Morphology (Baliga and Mehta, 2015). To my knowledge, this is the first documented analysis of the kinematics of feeding in cleaner fishes.

From these studies, I have discovered that cleaning is associated with low-displacement, fast jaw movements that allow for rapid gape cycles on individually-targeted items.

Cranial morphology of three cleaner wrasses. From top to bottom: Labroides dimidiatusLarabicus quadrilineatus, and Thalassoma lutescens. Images in the right column are of cleared & double-stained specimens. 

A bluestreak cleaner wrasse (Labroides dimidiatus) inspecting a Spanish hogfish (Bodianus rufus)

I am committed to pursuing graduate research, postdoctoral work and ultimately a faculty position at a research
institution. My ideal career would enable me to immerse myself in research while still providing me with the
opportunity to teach and work right alongside the next generation of scientists.

Thalassoma lutescens (adult)

I feel that research and teaching complement one another; I appreciate that each teaching opportunity I have had has enabled me to solidify my understanding of the topics involved while connecting with bright and eager minds. I strongly feel it is my responsibility as a scientist to take an active role in fostering science education.

I am excited to not only continue building on the rewarding experiences I have had, but also to continue finding ways help uplift my community.