The substances that communicate information between individuals (called semiochemicals) are at the center of chemical ecology research. Living organisms (plants, animals, fungi, bacteria) use semiochemicals to communicate information regarding feeding and diet, health and nutrition, kinship and social order, reproductive status, and much more. Chemical communication occurs among organisms of the same species as well as between different species. Chemical ecologists study these interactions by identifying the semiochemicals that portray the information, investigating the responses to the semiochemicals, revealing the receptor systems involved in communication, and exploring the evolutionary origins of communication and response.

Chemical Ecology and Communication Research at Monell

Scientists at Monell actively study chemically-mediated interactions in a variety of mammals, including humans. For example, researchers are working to identify and understand the presence of “odortypes” in mammals. Odortypes are genetically-based odors of individual identity. These unique odors aid in mate selection, promote genetic diversity, and minimize inbreeding. Our scientists have isolated the genes that encode odortypes and are investigating how the coding is accomplished. Studies are underway to explore the influence of odortypes on social interactions in animals and humans.

Research at Monell has demonstrated that infection with a retrovirus results in a change in the body odor of infected mice. The odor cues associated with infection are present in whole body and urine sources and can be discriminated by trained detector mice. The odor change is not associated with any clinical changes in the mouse’s health and appears to result from some alteration in the infected animal’s immune system. Similarly, Monell research has further demonstrated that mice with experimentally induced lung tumors can be identified by changes in body odor.

A hallmark of chemical ecology research is the combination of behavioral assays with chemical and biometrical analyses. Concurrent to behavioral testing of odortypes and disease detection, semiochemicals sources are subjected to gas chromatography mass spectrometric analyses for characterization of the volatile compounds. Chromatographic data is analyzed by partial least-squares regression to produce multivariate models for discrimination of control and disease samples based upon volatile responses.

In conjunction with the U.S. Department of Agriculture, Monell scientists study the mechanisms that underlie foraging and predation behavior in wildlife species. A better understanding of the chemical signals used by wildlife to identify prey items (both plant and animal) is leading to the development of attractants and repellents. For example, extensive research of protein hydrolysates is providing information regarding herbivore repellents. This knowledge is being applied to protect threatened species, minimize crop damage, control invasive species, and reduce human-wildlife conflicts.

A wide variety of chemical ecology research is being conducted at Monell, including studies intended to:

• Investigate how chemical signals and postingestive consequences of food ingestion are integrated into conditioned behaviors
• Use molecular modeling techniques to develop new non-lethal chemical repellents against wildlife pest species
• Formulate attractants that can be used to deliver vaccines to wildlife for diseases such as Lyme disease and rabies
• Develop baiting attractants for control of destructive invasive species such as brown treesnake or feral swine
• Determine the influence of odortypes on human social communication
• Evaluate gender differences in olfactory cross-adaption and self-adaption to human sweat odor
• Understand exactly how genes determine individual odortypes
• Evaluate the role of human body odors on hormonal cyclicity in women
• Determine behavioral implications of olfactory disease detection in populations of wild animals
• Investigate the effects of aging on body odor of mice
• Explore the accessory olfactory system in human and animal models
• Evaluate biosensor models for detection of zoonotic diseases such as malaria or type A influenza