In which we discover that evolution on islands can actually be slower than on continents. Why? Read this press release or our paper to find out. Congratulations to lead author Jhan Salazar (undergraduate) and co-author Brooke Bodensteiner (graduate student)!
A new book is out! Behavior of Lizards: Evolutionary and Mechanistic Perspectives features a chapter on foraging behavior by Martha Muñoz and colleagues. The researchers integrate sensory ecology and evolutionary perspectives to discuss how lizards find and acquire food. Lizards are exceptionally diverse where foraging strategies are concerned: some are visual foragers, whereas others use chemoreception or thermosensation or, in a few cases, auditory cues. How does it all fit together in the lizard tree of life? Read to find out!
The Muñoz Lab made a splash at Society for Integrative and Comparative Biology conference in Tampa, Florida, this year was eventful with five talks and Martha organizing a symposium!
Martha Muñoz presented work on a recent project, with Jhan Salazar and colleagues from Universidad Icesi, investigating the island effect with regards to rates and patterns of evolution through the lens of thermal physiological trait diversity. Due to ecological opportunity, island lineages are well known for fast rates of trait evolution. Surprisingly, however, they discovered slower rates of heat tolerance evolution in the island lineages. Moreover, island anoles are evolving towards higher trait optima. The results are largely explained by greater thermoregulation on islands. Despite island and mainland anoles occurring in similar thermal environments, island lizards thermoregulate more. The major result from this study is that ecological opportunity (release from predators and competitors) on islands can reduce the intrinsic costs of thermoregulation. The surprising result, therefore, is that ecological opportunity may actually slow, rather than accelerate, trait evolution!
Post-doc Vincent Farallo presented work, co-authored by Martha, in the behavioral physiology session on the importance of incorporating physiology and behavior when assessing how species, especially montane endemics, will be impacted by climate change. Their research focused on anoles from the island of Hispaniola and showed that, when incorporating behavior and physiology, montane endemic species will increase potential activity time under climate change. However, their widespread competitor will also see increased activity, indicating the montane endemics are still likely at risk, but not directly from warming temperatures. Understanding the mechanism of species decline will be critical for mitigating the impacts of climate change. The lab will be expanding on this topic, focusing on montane endemic plethodontid salamanders, during 2019 and beyond.
Henry Camarillo, Ph.D. student, presented some of his Master’s research examining the role of morphology on performance in fish from hydrogen sulfide streams. Henry measured escape performance, steady swimming performance, and gill ventilation between populations of fish from sulfidic and nonsulfidic streams. Fish from nonsulfidic populations were better at escape swimming and had higher gill ventilation frequency. Fish from sulfidic populations were more energy efficient swimmers and performed better at steady swimming. In addition, I found that there are functional trade-offs between escape performance and swimming performance as well as functional facilitation between escape performance and gill ventilation frequency. Correlation between morphology and performance was found in females, but not in males.
Brooke Bodensteiner (Ph.D. student) presented her talk, co-authored by Martha, in the Division of Phylogenetics and Comparative Biology Best Student Presentation (the Wake Award) examining the pattern and temporal dynamics of adaptive radiation in Hispaniolan anoles. Specifically examining the diversification along structural habitat niche and thermal physiological niche. Finding that patterns of physiological and morphological evolution are distinct, such that ecomorphs do not cluster together in physiological trait space. We propose that the exceptional diversity of Caribbean anoles may be driven by the combined influence of physiological and morphological evolution, and that physiological divergence along environmental gradients are an equally important, though less appreciated, aspect of adaptive radiation.
Martha published a new paper in the Journal of Thermal Biology. Behavioral thermoregulation and physiological plasticity have long been recognized as key traits that should buffer organisms from the pernicious effects of climate warming. Behavior and plasticity, however, are usually studied independently. By examining patterns of thermoregulation and physiological plasticity in a single population over the course of a year, the researchers demonstrated that the traits are not independent – thermoregulation is constrained by physiological plasticity. When considered in the framework of environmental warming, lizards might have a limited ability to mount a strong buffering response. This research is part of a new and ongoing collaboration with scientists at the Universidad Nacional Autónoma de México (UNAM). The next phase of this research is to conduct a macroevolutionary study of behavior and physiology across the whole clade of spiny lizards. Stay tuned!
Today, Martha and Muñoz Lab graduate student, Brooke Bodensteiner, published a paper in the inaugural issue of Integrative Organismal Biology, a new open access journal through the Society for Integrative and Comparative Biology. In this conceptual paper, Martha and Brooke bridge two classic hypotheses – Janzen’s Hypothesis and the Bogert Hypotheses – which have been foundational concepts in biology for several decades. The result is a synthesis that links climatic variation, organismal behavior, physiological variation, and rates of evolution in a single conceptual framework. Specifically, Martha and Brooke argue that high climatic variation favors behavioral thermoregulation, which limits physiological turnover across environments, and results in slower evolution. In contrast, low climatic variability limits behavior, fosters physiological turnover, and results in faster evolution. They illustrate these connections using empirical data from Caribbean Anolis lizards. This integrative conceptual framework is widely applicable to a number of fundamental questions in organismal biology, ecology, and evolution.
One of the coolest aspects of being a faculty member is getting to design new courses. This fall, I had the absolute privilege of leading a new course: Life in the Anthropocene. We talked about all the ways in which humans have changed selective pressures in the environment, and how those selective pressures impact organisms. It was a total blast! Honestly, I can’t thank the students enough for the thoughtful discussion and the pure joy of this course. Today was the last day and students discussed their term papers. Undergraduate Nathan Clark brought in his own products of human-induced selection: Ultra hot peppers! They were so hot he needed to wear gloves. I’ll miss this class so much!
This past week, we had the privilege of hosting Dr. Will Ratcliff for our EEB seminar series. Dr. Ratcliff’s work bridges evolution, microbiology, and cellular/molecular biology to address a core question in biology: How does multicellularity evolve? Thanks again to Will, who gave a rocking talk and was a wonderful visitor.
Hosted by Dr. David Blackburn, Martha recently visited the University of Florida to give seminar. During her visit, she was able to tour the Caribbean archaeology collections and visit nearby swamps. Thanks to everyone in Biology and the Museum of Natural History for such a memorable visit!