|
||||
    
    
     |
  |
Each month, a group of students and faculty from the College of Agriculture and Life Sciences gather at the home of two researchers to discuss matters such as the genetics of feeding behavior in insects. In true Socratic fashion, these scientists and their students from different disciplines are learning from each other through questioning and discussion. The discussion sessions, which usually deal with some topic of scientific controversy, are key to N.C. State University’s new W.M. Keck Program for Behavioral Biology. The program, involving researchers from several scientific disciplines, was recently established with a grant of $800,000 from the W.M. Keck Foundation.
In many ways, the program represents the best of what goes on in a university setting: cross-disciplinary research, intellectual discourse and seminars that draw top researchers to campus. In fact, the behavioral biology program actually got its start through discussion groups like those held each month, according to Dr. Robert Anholt, associate professor of zoology and director of the program.
A grassroots movement The group started out discussing research interests and contributing expertise to enrich each other’s research efforts
Two years ago, Anholt received funding for a university seminar program to bring in researchers recognized as experts in their fields. The program was very popular, with some speakers attracting standing-room-only crowds. With the success of the seminar program, the group wanted to move forward by providing support for outstanding graduate students to work in interdisciplinary research projects. They applied for funding from the W.M. Keck Foundation, a Los Angeles-based charitable organization that has supported programs and facilities in science, engineering, natural resources, medicine and higher education since 1954. When a foundation representative asked, “What is behavioral biology?” Vandenbergh responded by saying, “Behavior is the window through which we can view all of biology.” The university learned last summer that the Keck Foundation would fund the program, and in September, the first predoctoral fellowship was awarded to Indrani Ganguly of Bombay, India. Ganguly works with Anholt and Mackay, studying the molecular genetics of odor-guided behavior in fruit flies. Two sides to all questions The five researchers who make up the program study a diverse range of issues involving vertebrates and invertebrates, agricultural pests and urban pests. One thing that makes the group unusual is that some members are interested in proximate causes of behavior, while others study ultimate causes, said Gould. Proximate causes involve identifying the specific mechanism that causes a behavior. In some species, for instance, pheromones released by females attract males for mating. Therefore, pheromones are the proximate cause of attraction. Those who study ultimate causes of behavior, or what Gould calls the “evolutionary perspective,” want to discover why a particular behavior evolved. What genetic mechanisms evolved to cause insects to eat certain foods?
Identifying differences
Using quantitative genetic techniques, the researchers are studying the difference in the two insects to determine if the genes that cause the insect to prefer cotton are the same as genes that control the preference for soybeans. The researchers are working with chemical compounds found in the insects’ plants of choice to see if there are genes coding for preferences to these chemicals. “Long term, these studies could lead to new strategies for pest control. We could engineer plants without the attractant chemicals or get rid of genes in the insect that allow it to feed on certain plants,” Gould said. Pheromone-induced behaviors Schal, who researches cockroach behavior, says his objective is to develop environmentally friendly ways of fighting these and other urban pests.
To reproduce, female cockroaches emit a pheromone, or chemical odorant, that attracts males. Odorant-binding proteins in the males’ antennae bind with this pheromone and deliver it to a receptor in the brain.
Schal is also working with Mackay to examine variations in pheromones among Drosophila, or fruit flies, from around the world.
Olfaction in fruit flies Mackay studies complex traits that are controlled by multiple genes interacting with each other and with the environment. Most behaviors are considered complex traits, she said, as are such factors as heart rate, weight, height and life span. She has learned that some genes, which are not sex-linked, can produce different results in males and females. Some genes will increase life span in males, while shortening life span in females. Anholt and Mackay, who are married, are studying olfaction in Drosophila because a great deal is known about the Drosophila genome. They want to learn more about how chemical signals are perceived by animals and to identify the genetic mechanisms that determine what animals can smell. By manipulating the genome and observing how fruit flies from different genetic lines respond to odor, they hope to learn more about the genes that control olfaction. Testosterone as a pheromone Vandenbergh has been involved in the study of mammalian behavioral endocrinology with a focus on the interactions between hormones and reproductive behavior. One recent research project has involved the study of chemical communication among embryos in the womb, or in utero. Researchers learned that female mice that were located in utero between two males behaved later in life much differently from females that were located between two females or a male and a female. The 2M females — those located between two males before birth —were characterized by late onset of puberty, poor maternal behavior and more aggressive behavior than their 1M or 0M counterparts — those located next to one male or no males. In addition, the 2M females were more likely to give birth to males and had genitalia different from other females. The finding seems to indicate that, in utero, testosterone from the male embryos acts as a pheromone to female embryos, Vandenbergh says. “This opens up the whole area of prenatal exposure to different compounds.” Strength in numbers Vandenbergh’s research on how animals respond to chemical signals overlaps with Anholt’s interest in how olfactory signals affect cellular and molecular functions. In fact, the interdisciplinary nature of the program is one of its greatest strengths, leading researchers to look into an issue from a number of perspectives. “We learn a lot from each other,” says Schal. The entomologist says he has expanded his interest in pheromone-regulated behavior in insects and is now reading colleagues’ papers about pheromones in rodents and pigs. Mackay says interactions across disciplines spark new ideas.
|
||
Socrates
would be so pleased.
The
grant will provide fellowships for graduate students and postdoctoral
fellows to work with researchers.
The key research faculty members in the program
are Anholt, a zoologist with an interest in olfaction, the perception
of odors; Dr. Trudy Mackay, William Neal Reynolds Professor of
Genetics, specializing in quantitative genetics; Dr. Fred Gould,
William Neal Reynolds Professor of Entomology, specializing in
evolutionary genetics, adaptive behavior and ecology; Dr. Coby
Schal, Blanton J. Whitmire Professor of Entomology, specializing
in behavioral physiology of insects; and Dr. John Vandenbergh,
professor of zoology, specializing in behavioral physiology and
endocrinology of mammals.
Behavioral biology, the integrated study of the
principles of animal behavior, holds great promise for biomedical
and agricultural research in the next century. The researchers
focus on questions of complex animal behavior, such as why insects
choose to eat certain foods and not others, how animals perceive
odor or what mechanisms drive aggressive and reproductive behavior.
What they learn could lead to improvements in agricultural and
urban pest control as well as a better understanding of complex
human behaviors, such as drug addiction, aggression and antisocial
behavior.
Interfering
with the receptor in the brain of the male cockroach could be
one strategy for controlling this urban pest, which has been
blamed for asthma epidemics in some high-density urban dwellings.