Brent Horton, PhD

Dr. Brent M. Horton

Dr. Brent M. Horton

Assistant Professor, Vertebrate Ecological Physiology & Behavioral Ecology


brent.horton@millersville.edu
Office: Caputo 115
Phone: (717) 871 4080

Office Hours

M: 01:00 – 02:45 p.m.
T: 02:30 – 04:30 p.m.
R: 02:30 – 03:45 p.m,

Additional Information

Education:

B.S., Wildlife Biology, Colorado State University
Ph.D, Zoology, University of Maine

Courses Taught:

BIOL 101  Foundations of Biology
BIOL 211  Concepts of Zoology
BIOL 435  Animal Physiology
BIOL 437 Endocrinology 
BIOL 472  Seminar in Behavioral Ecology
BIOL 471 Behavioral Ecology*
BIOL 471  Mechanisms of Behavior 
*Summer Course at Chincoteague Bay Field Station
 
Areas of Specialization:

Animal Behavior, Behavioral Ecology, Ecological Physiology, Behavioral Endocrinology/Neuroendocrinology, and Ornithology.

Research Interest(s):

As an integrative behavioral and physiological ecologist, I seek to understand the physiological underpinnings of the behavioral strategies that distinguish vertebrate life histories. Hormones, particularly steroids, have pleiotropic effects on physiology and behavior, and growing evidence suggests they mediate the behavioral strategies that characterize life histories. The underlying genetic bases for most hormone-mediated traits remain elusive, however, limiting our understanding of the heritable substrates on which selection can act to shape behavioral phenotypes. To address this problem, I integrate advances in neuroendocrinology and molecular genetics with traditional behavioral ecology to deconstruct the neuroendocrine and genomic architecture of behavior. My approach is to study natural models and to combine field experiments with laboratory analyses to advance our understanding of the proximate and ultimate mechanisms that shape behavioral strategies and, ultimately, life histories.

I am currently working on two unique models systems:

White-throated Sparrows (Zonotrichia albicollis) These sparrows are a unique and powerful model for studying the neuroendocrine and genetic bases of social and reproductive behavior. They exhibit genetically based plumage polymorphism, and the two color morphs, white-striped and tan-striped, differ in aggression, parenting, and mate-seeking behaviors. Importantly, color morph and behavioral strategy segregate according to the presence or absence of a structural rearrangement of chromosome 2. This rearrangement, which captures numerous neuroendocrine genes, highlights a genomic region for a targeted investigation into the neurogenetics of behavior. For some time now, I have been working with Drs. Donna Maney and Wendy Zinzow-Kramer (Emory University), and Dr. James Thomas (National Institutes of Health) , to better understand how hormones and gene expression in the brain underlie alternative behavioral strategies in these fascinating sparrows.

Wire-tailed Manakins (Pipra filicauda) In this Amazonian species, males engage in stable and cooperative display partnerships to attract females, and these partnerships form the basis of a complex social network. Male reproductive success, which is highly skewed, is a function of social status and degree of social connectivity; that is, territrorial males with more display partners enjoy greater reproductive success. Moreover, variation in male testosterone levels correlates with their social status. This pattern implicates testosterone as a potential  mechanism underlying behavioral phenotype, social rise, and, ultimately, social network structure and fitness in male manakins. Meanwhile, the fact that territorial males with high testosterone maintain stable and cooperative display partnerships with other males is paradoxical, as testosterone is well known for promoting male-male aggression. I am working with Dr. T. Brandt Ryder (Smithsonian National Zoo) and Dr. Ignacio Moore (Virginia Tech) to integrate the desparate fields of neuroendocrinology, genetics, and social network theory to better understand the neuroendocrine and genetic bases for social networking in vertebrates.

Selected Publications:

Zinzow-Kramer, WM, BM Horton, CD McKee, JM Michaud, GK Tharp, JW Thomas, EM Tuttle, S Yi, & DL Maney. 2015. Genes located in a chromosomal inversion are correlated with territorial song in white-throated sparrows. Genes, Brain & Behavior 14: 641-654.

Maney, D.L., B.M. Horton, & W.M. Zinzow-Kramer. 2015. Estrogen receptor alpha as a mediator of life-history trade-offs. Integrative & Comparative Biology 55(2): 323-331.

Horton, B.M., I.T. Moore, & D.L. Maney. 2014. New insights into the hormonal and behavioural correlates of polymorphism in white-throated sparrows, Zonotrichia albicollis. Animal Behaviour 93: 207-219.

Horton, B.M., W.H. Hudson, E.A. Ortlund, S. Shirk, J.W. Thomas, E.R. Young, W. Zinzow-Kramer, & D.L. Maney. 2014. Promoter polymorphism and differential expression of estrogen receptor α in a species with alternative behavioral phenotypes. Proceedings of the National Academy of Sciences 11: 1443-1448.

Zinzow-Kramer, W.M., B.M. Horton, & D.L. Maney. 2014. Evaluation of reference genes for quantitative real-time PCR in songbird brain, pituitary, and gonad. Hormones and Behavior 66: 267 – 275.

Grozhik, A.V., C.P. Horoszko, B.M. Horton, Y. Hu, D.A. Voisin, & D.L. Maney. 2014. Hormonal regulation of vasotocin receptor mRNA in a seasonally breeding songbird. Hormones & Behavior 65: 254-263.

Horton, B.M., Y. Hu, C.L. Martin, B.P. Bunke, E.S. Matthews, I.T. Moore, J.W. Thomas, & D.L. Maney. 2013. Behavioral characterization of a white-throated sparrow homozygous for the ZAL2m chromosomal rearrangement. Behavior Genetics 43(1): 60-70.

Ballentine, B., B.M. Horton, E.T. Brown, & R. Greenberg. 2013. Divergent selection on bills contributes to non-random mating between swamp sparrow subspecies. Animal Behaviour 86: 467-473.

Horton, B.M., M.E. Hauber, & D.L. Maney. 2012. Morph matters: Aggression bias in a polymorphic sparrow. PLoS ONE 7(10): e48705.

Ryder, T.B., B.M. Horton, M. van den Tillaart, J. Morales, & I.T. Moore. 2012. Proximity data-loggers increase the quantity and quality of social network data. Biology Letters 8: 917-920.

Rivers, J.W., S. Young, E. Gonzalez, B.M. Horton, J. Lock, & R.C. Fleischer. 2012. High levels of relatedness between brown-headed cowbird nestmates in a heavily-parasitized host community. The Auk 129(4): 623-631.

Ryder, T.B., B.M. Horton, & I.T. Moore. 2011. Understanding testosterone variation in a tropical lek-breeding bird. Biology Letters 7(4): 506-509.

Biggins, D.E., J.L. Godbey, B.M. Horton, & T.M. Livieri. 2011. Movements and survival of black-footed ferrets associated with an experimental translocation in South Dakota. Journal of Mammalogy 92(4): 742-750.

Horton, B.M. & R.L. Holberton. 2010. Variation in baseline corticosterone and the adrenocortical response in breeding white-throated sparrows. The Auk 127(3): 540-548.

Horton, B.M., J.M. Yoon, C.K. Ghalambor, I.T. Moore, & T.S. Sillett. 2010. Seasonal and population variation in breeding testosterone in male orange-crowned warblers, Vermivora celata. General & Comparative Endocrinology 168: 333-339.

Horton, B.M., & R.L. Holberton. 2009. Corticosterone manipulations alter morph-specific nestling provisioning behavior in male white-throated Sparrows, Zonotrichia albicollis. Hormones & Behavior 56: 510-518.

Horton, B.M., J.A. Long, & R.L. Holberton. 2007. Intraperitoneal delivery of exogenous corticosterone via osmotic pump in a passerine bird. General & Comparative Endocrinology 152: 8-13.