3258 TAMU
College Station, TX 77843-3258

Office:
Butler Hall
Room 204A
979-845-3614

Lab:
Butler Hall
Room 204
979-458-0914

Fax: 979-845-2891
Email: grosenthal@mail.bio.tamu.edu

Gil Rosenthal is an Assistant Professor in the Department of Biology. He received a Bachelor of Arts degree in Biology from Harvard University in 1993, then went on to receive his Ph.D. with Dr. Michael Ryan at the University of Texas at Austin in 2000. Rosenthal's dissertation focused on the evolution of visual mating signals and mating preferences in swordtails, small livebearing fish from central Mexico. His work showed that sexually-selected signals can evolve in response to broad, permissive biases on the part of females, and that these biases can be shared by predators as well as conspecifics. Females have evolved reduced preferences for extreme traits, and males have evolved more modest traits, in response to predation pressure. Rosenthal went on to a two-year stint as an NRSA postdoctoral fellow in Dr. Karen Marchetti's lab at the University of California, San Diego, where he began work on the evolution of reef-fish colors. The Neotropics, with closely-related species living in strikingly different visual environments in the eastern Pacific versus the Caribbean, provide an ideal model system for studying the effects of the visual environment on signal design and visual perception. In 2002, he joined Boston University's Biology Department as an Assistant Professor based at the Marine Biological Laboratory in Woods Hole, MA, where he continued his reef-fish work and started focusing on mate choice and evolutionary genetics in a swordtail hybrid zone. He moved to Texas A&M in late 2005 and continues to work on the evolution and ecology of animal communication. In addition to facilities at TAMU, his lab maintains the CICHAZ research station in Calnali, Hidalgo, Mexico.

Lab Webpage

My principal research goal is to address the diversity of systems animals use to communicate with one another, both at the level of proximate mechanisms and in an evolutionary sense. Effectively, I am asking how the biotic and abiotic environment shapes the relationship between a communication signal and its receiver. Research in my laboratory takes an integrative approach, combining field observations and measurements of communication parameters with laboratory analyses of behavioral, physiological, and molecular mechanisms. We use a range of techniques in the field and in the lab, including video playback of computer animations, spectroradiometry, and microspectrophotometry. My own primary focus is on visual and olfactory communication in teleost fishes, but students in my laboratory work on a broad range of systems and topics in behavioral ecology.

Mate choice and evolutionary genetics in hybrid zones
Males typically express complex arrays of sexually-dimorphic mating signals. How do females integrate information about such arrays into decisions about whom to mate with; and how do such decisions affect the evolution of conspicuous arrays? This question is fundamental to understanding sexual selection and speciation. Our ongoing research addresses this question by taking advantage of a remarkable phenomenon in nature: streams in highland Mexico where two species of swordtail fish (family Poeciliidae: Xiphophorus birchmanni and X. malinche) interbreed, forming a hybrid zone. Why do females mate with the "wrong" species – do mating preferences for conspicuous traits cause them to make mistakes? Are species of one species more likely than the other to make such mistakes? To address these questions, we collaborate with Dr. Francisco García de León’s lab (CIBNOR) to collect data on the distribution of DNA markers in the wild; we then combine these data with a variety of techniques for measuring female mating preferences. Computer-animated movies of males performing courtship behavior can be created to display any set of visual characteristics; female preferences can thus be measured for any combination of traits of either parental species. We are also investigating the role of pheromones in mate choice: males produce species-typical chemical cues, and females typically prefer the chemical cues of conspecifics. In hybrid zones, however, chemical cues are masked by environmental contaminants. Ongoing work seeks to characterize the chemical nature of pheromone cues and their susceptibility to environmental effects.

Evolution of visual communication in Neotropical reef fishes
The conspicuous color patterns of tropical reef fishes have long posed an evolutionary puzzle, since in most cases they cannot be explained readily by standard models of signal evolution. Alfred Russell Wallace, co-founder of evolutionary theory, suggested that these patterns might in fact be cryptic in the complex, colorful environment of a coral reef. A century later, Konrad Lorenz argued that species-typical color patterns might function as iconic indicators of species identity for mating and aggressive interactions. We take advantage of a powerful model system for addressing these questions, the reef fishes of the Neotropics. The formation of the Isthmus of Panama caused widespread extinction of reef-building corals in the eastern Pacific, yielding darker, more homogeneous visual backgrounds and murkier water. Our research focuses on how the close relatives of Caribbean reef fishes have adapted to this divergent visual environment. The Neotropical fauna are a remarkable system for comparative biology, with over 100 fish species pairs with Caribbean and eastern Pacific representatives. By comparing visual perception and visual signal form across species pairs, we are finding support for Wallace’s suggestion that signals have evolved to minimize conspicuousness against colorful backgrounds. Current research focuses on the visual ecology of spatially-varying patterns and their function in species recognition. The visual environment of the eastern Pacific closely resembles that of disturbed coral reef environments, making this system a useful model for studying the impact of environmental disturbance on visual communication.

H. S. Fisher and G. G. Rosenthal 2007. Male swordtails court with an audience in mind. Biol. Lett. 3: 5-7.

S. W. Coleman and G. G. Rosenthal 2006. Swordtail fry attend to chemical and visual cues in detecting predators and conspecifics. PLoS One 1: e118.

H.S. Fisher and G.G. Rosenthal 2006. Female swordtail fish use chemical cues to select well-fed mates. Anim. Behav. 72: 721-725.

H. S. Fisher , B. B. M. Wong , and G. G. Rosenthal 2006. Alteration of the chemical environment disrupts communication in a freshwater fish. Proceedings: Biological Sciences 273: 1187-1193.

B. B. M. Wong and G. G. Rosenthal 2006. Female disdain for swords in a swordtail fish. Am. Nat. 167:136-140.

B. B. M. Wong, H. S. Fisher, and G. G. Rosenthal 2005. Species recognition by male swordtails via chemical cues. Behav. Ecol. 16: 818-822.

G. G. Rosenthal , A. S. Rand, and M. J. Ryan 2004. The vocal sac as a visual cue in anuran communication: an experimental analysis using video playback. Anim. Behav. 68: 55-58.

G. G. Rosenthal , X. F. de la Rosa Reyna, S. Kazianis, M. J. Stephens, D. C. Morizot, M. J. Ryan, and F. J. García de León 2003. Dissolution of sexual signal complexes in a hybrid zone between the swordtails Xiphophorus birchmanni and Xiphophorus malinche (Poeciliidae). Copeia 2003: 299-307.

G. G. Rosenthal , M. J. Ryan, and W. E. Wagner, Jr. 2002. Secondary loss of preference for swords in the pygmy swordtail Xiphophorus nigrensis (Pisces: Poeciliidae). Anim. Behav. 63: 37-45.

G. G. Rosenthal , T. Y. Flores Martinez, F. J. García de León, and M. J. Ryan 2001. Shared preferences by predators and females for male ornaments in swordtails. Am. Nat. 158: 146-154.

M. J. Ryan and G. G. Rosenthal 2001. Variation and selection in swordtails. In Model Systems in Behavioral Ecology, L. A. Dugatkin ed., Princeton University Press, 133-148.