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Indiana University Bloomington

Spring 2013 Animal Behavior Speakers

Mark Frye

Mark Frye

University of California, Los Angeles (Research Page)

Date: February 8, 4:00 PM

Location: Myers Hall 130

Title: "Olfactory Feature Detection in Flies"

Abstract

Virtually all mobile animals are equipped with a sense of smell and track chemical features of the world. Despite separation by 500 million years of evolution, there is great structural and functional similarity between arthropod and mammalian olfactory systems. This is due in part to the physics of fluid flow carrying the chemical molecules, which are similarly constrained for both groups. As such many qualitative properties of chemotaxis behavior are shared among taxa. Yet we have a remarkably incomplete understanding of the algorithms (list of rules) that define an odor feature, and then transform this sensory perception into an adaptive behavioral response. We make use of a virtual reality flight simulator equipped with a narrow odor plume in which a single fly is suspended within a magnetic field, free to orient relative to the plume, and followed with infrared video. We can manipulate the type of odorant and its temporal pattern. We then manipulate the expression of olfactory receptor genes, thereby altering what the animal is able to smell, and neuromodulatory signaling genes, thereby altering how odor signals influence global behavioral states. In combination, these techniques allow us to identify how specific properties of a chemical feature such as spatial intensity gradient, temporal pattern, and hedonic valence (i.e. attractiveness vs. aversiveness) are manifest in odor tracking behavior of flying Drosophila, and through which neural processing pathways. Finally, the flight simulator is surrounded by an electronic visual display, which we use to actively manipulate the fly's panorama and investigate how well-known visual gaze stabilizing reflexes operating in flies and humans alike are used to stabilize flight heading along an otherwise invisible and unpredictable chemical plume.

Mark Alkema

Mark Alkema

University of Massachusetts (Research Page)

Date: March 1

Location: TBD

Title: "The Neuroethology of C. elegans' Escape"

Abstract

Escape behaviors are crucial to survive predator encounters. Touch to the head of Caenorhabditis elegans induces an escape response where the animal rapidly backs away from the stimulus and suppresses foraging head movements. The coordination of head and body movements facilitates escape from predacious fungi that cohabitate with nematodes in organic debris. An appreciation of the natural habitat of laboratory organisms, like C. elegans, enables a comprehensive neuroethological analysis of behavior. I will present the neuronal mechanisms and the ecological significance of the C. elegans touch response.

Jeff Riffell

Jeff Riffell

University of Washington (Research Page)

Date: March 8

Location: TBD

Title: "Neuroecology: The Dynamics of Scent and Search Behavior"

Abstract

Chemical communication mediates a variety of critical ecological processes. Sensory perception of chemical signals, for example, strongly influences reproduction, foraging, and habitat selection. In this talk, I will show that the physiological bases of olfactory navigation play important roles in regulating behavior and mediating ecological interactions. I will illustrate this point with examples from 1) pollinator attraction to flowers, where flower odor preference and learning shape the selectivity of the olfactory system in bees and moths, which in turn mediates plant-pollinator associations in the field, and 2) mosquito olfactory behavior, where molecular mechanisms mediating behavior are important in innate and learned preferences for blood meals. While these systems operate under different constraints, all employ similar behavioral search strategies (flux detection) as a means to locate odor sources, and exhibit both innate and learned olfactory behaviors. In studying these different systems, comparisons can be made to understand how chemical communication systems operate depending upon the environment in which they exist.

Frances Champagne

Frances Champagne

Columbia University (Research Page)

Date: March 29

Location: IMU Frangipani Room

Title: "Developmental Programming of Behavior via Epigenetic Pathways"

Abstract

Though genetic variation can have a significant impact on neurobiological and behavioral outcomes, it is evident that environmental experiences can similarly affect biological processes leading to altered neurobehavioral characteristics. Variation in gene regulation has emerged as a mechanism through which the environment can interact with genes to allow for the emergence of divergent phenotypes. Moreover, there is increasing evidence that environmentally-induced changes in gene expression may be achieved through epigenetic pathways. Epigenetic modifications—molecular pathways through which transcription is altered without altering the underlying DNA sequence—play a critical role in the normal process of development and are potentially heritable. A broad range of "experiences" has been demonstrated to alter epigenetic pathways, including prenatal exposure to stress and toxins, postnatal variation in maternal care, and the experience of enhanced social/physical environments. Here, I will describe evidence implicating epigenetic factors, such as DNA methylation, histone modifications, and microRNA in the link between experiences occurring during development and altered neuroendocrine and behavioral outcomes. I will also discuss how these molecular events are hypothesized to contribute to the transgenerational inheritance of traits.

John Godwin

John Godwin

North Carolina State University (Research Page)

Date: March 30

Location: Myers Hall 130

Title: "Neuroendocrine Regulation of Sexual Plasticity in Fishes"

Abstract

The study of sex differences has produced major insights into the organization of animal phenotypes and the regulatory mechanisms generating behavioral variation from similar genetic templates. Coral reef fishes display an extraordinary diversity of sexual expression including simultaneous hermaphroditism and functional, socially controlled sex change. These systems provide powerful models for understanding gonadal and non-gonadal influences on behavioral and physiological variation. We work with a species, the Caribbean bluehead wrasse (Thalassoma bifasciatum) that exhibits female-to-male functional sex change and discrete alternate male mating phenotypes. This talk will focus on transduction of social cues into reproductive responses by sex-changing female wrasses, how patterns in bluehead wrasses may relate to similar patterns in diverse range of fishes that display alternate mating phenotypes, and how we are using genomic approaches to understand the development and evolution of these sexual phenotypes.