Wildlife Services

Protecting People 

Protecting Agriculture 

Protecting Wildlife

National Wildlife Research Center

FY 2017

Chemosensory Tools for 

Wildlife Damage Management

Contact Information:

Dr. Bruce Kimball 

Research Chemist 

c/o Monell Chemical Senses Center 

3500 Market Street 

Philadelphia, PA 19104 

Phone: (267) 519-4930 

FAX: (267) 519-4930 

E-mail:

bruce.a.kimball@aphis.usda.gov

Web site: www.aphis.usda.gov/

wildlifedamage/nwrc/

Groups Affected:

Agricultural producers

Consumers of agricultural products

Industry groups

Federal and state wildlife and

natural resource managers

U.S. citizens

Major Cooperators:

APHIS Veterinary Services

British Columbia Ministry of

Forests and Range

Case Western Reserve University

Colorado State University

Drexel University School of

Medicine

James Madison University

Karolinska Institutet (Sweden)

Monell Chemical Senses Center

University of Pennsylvania

U.S.D.A. Agricultural Research

Service

U.S. Department of Defense

U.S. Department of the Interior

Office of Insular Affairs

National Wildlife Research Center Scientists Use Chemistry to Resolve Wildlife Damage

Wildlife Services' (WS) National Wildlife Research Center (NWRC) is the only Federal research facility

devoted exclusively to resolving conflicts between people and wildlife through the development of

effective, selective, and socially responsible methods, tools, and techniques. 

NWRC scientists investigate the role of chemicals on animal behavior, such as foraging preferences,

locating food and mates, and flavor aversion. Through a basic understanding of chemosensory

science, NWRC research develops new or improves existing wildlife damage management tools, such

as diagnostic methods for detecting diseases in wildlife, and novel baits, lures and repellents. 

The NWRC Philadelphia, PA, field station is located at the Monell Chemical Senses Center. Monell is

the world's only non-profit scientific institute dedicated to basic research on taste and smell. It provides

access to specialized research opportunities focused on the development of nonlethal wildlife

repellents and attractants. Chemical ecology research involving olfactory, taste, and chemoreception

senses is emphasized.

Applying Science and Expertise to Wildlife Challenges

Chemosensory Aspects of Repellency. — Taste, smell, sight, and touch permit herbivores to detect

the chemosensory attributes of foods. These sensory cues, as well as an animal's personal

experiences, parental guidance and instinct, influence their foraging behaviors. Experiments by NWRC

scientists showed that persistent avoidance of repellent-treated foods results only when a toxin is

paired with the flavor of the food or repellent formulation. Furthermore, protein-based repellents (such

as protein hydrolysates) reduced food consumption by herbivores, but not omnivores. Because they

are plant eaters, herbivores likely experience conflicting chemosensory information when exposed to

protein hydrolysates. Researchers conclude that effective herbivore repellent formulations must be

applied directly to the food; and 2) have physiological or evolutionary consequences for the herbivore. 

Avian Influenza Detection from Fecal Odors. — Many diseases cause a change in body odors.

NWRC scientists and partners at the Monell Chemical Senses Center and Colorado State University

studied changes of fecal odors in mallards infected with the avian influenza (AI) virus. Laboratory mice

were trained to discriminate between feces from AI-infected and uninfected ducks, indicating a change

in odor. Chemical analysis then found the volatiles (compounds that emit unique odors or emission

patterns) associated with the odor changes to be acetoin and 1-octen-3-ol. These compounds have

also been identified as potential biomarkers for diagnosing gastrointestinal diseases in humans.

Researchers hypothesize that metabolites resulting from viral infection interact with bacteria in the

gastrointestinal system of ducks to produce “odor signatures” indicating the presence of the AI virus.

Ongoing research is focused on whether odor changes can be used for surveillance of AI in waterfowl.

In particular, researchers are interested in whether the odor change is specific to the AI pathogen or if it

is merely a general response to a variety of pathogens normally found in birds. 

Training a Ferrets as a Disease Biosensor. — Recent avian influenza (AI) infection outbreaks have

resulted in global biosecurity and economic concerns. In previous NWRC studies, trained mice

correctly discriminated the health status of individual ducks on the basis of fecal odors when feces from

AI post-infection periods were paired with feces from AI pre-infection periods. More recently, NWRC

scientists and colleagues at Monell trained domesticated male ferrets (Mustela putorius furo) to

respond by scratching/pawing at the ground when detecting acetoin (a fecal compound previously

determined to be related to AI infection) in presented test samples. Ferrets rapidly generalized this

learned response to the odor of feces from AI-infected mallards. These results suggest that a trained

mammalian biosensor could be used in an AI surveillance program, resulting in significant savings over

current laboratory testing methods.

Adapting Wildlife Research for Studies of Human Health. — The chemical analysis paradigm

involving the use of volatile metabolites to detect disease lends itself to new discoveries in human

United States Department of Agriculture 

Animal and Plant Health Inspection Service
The U.S. Department of Agriculture is an equal opportunity employment provider and employer

health research. In a study with Children's Hospital of Philadelphia

(CHOP), NWRC and Monell researchers found that volatile

metabolites were specifically altered by brain injury in a manner

differing from general inflammation. Thus, monitoring changes in

the volatile metabolome may be a useful for the rapid diagnosis of

brain trauma and recovery. Additionally, researchers collaborating

with Case Western Reserve University discovered differences in

urinary volatiles between healthy mice and mice with human

mutations of an Alzheimer's disease gene. These findings in

animal models show that mutant gene expressions cause

identifiable urinary odors, which if uncovered in clinical

Alzheimer's patients, may serve as additional biomarkers for the

disease.

New Bait for Brown Treesnakes. — A native of Australia, Papua

New Guinea, and the Solomon Islands, the invasive brown

treesnake threatens the economy and ecology of Guam and is

currently the subject of a cooperative program to control its

population and prevent its spread throughout the Pacific Rim. For

many years, dead neonatal mice have been the gold standard

lure for baiting invasive brown treesnakes on Guam. However,

finding, keeping and using mice can be costly and messy. Dead

mouse bait also decomposes quickly in the tropics, rendering it

unacceptable to snakes. Recently, NWRC researchers tested a

new brown treesnake bait made of processed meat and an

artificial mouse fat mixture. Results showed the new bait was

eaten by snakes at rates similar to the current dead mouse bait. It

also remained viable and lasted longer under field conditions.

Researchers are continuing to streamline the manufacturing

process of the new bait. Current estimates indicate each new bait

could potentially cost about 50¢ less than the current mouse bait,

improving the cost-effectiveness of brown treesnake control

efforts.

Brown Treesnake Pheromones. — Pheromone-based

technologies are sometimes used as attractants to help control

invasive species. Pheromones are chemicals produced and

released into the environment by an animal that affect the

behavior or physiology of others of its species. Brown treesnakes

are an invasive species on Guam. The female snakes emit

“chemical trails” by releasing pheromones through their skin.

These trails stimulate and aid in reproduction by helping males

find receptive females. NWRC and James Madison University

researchers revealed that sex identity in brown treesnakes can be

determined by the ratio of specific skin lipids or pheromones

(ketomonoenes to ketodienes). Researchers also discovered that

skin lipid ratios were influenced by changes in the snakes' sex

hormones. These findings will aid in the development of

pheromone-based tools for brown treesnake management.

Selected Publications:

Selected Publications:

Kimball, B.A. 2016. Volatile metabolome: Problems and

prospects. Bioanalysis. 8:1987-1991. doi: 10.4155/bio-2016-0203. 

Kimball, B.A., D.A. Wilson, and D.W. Wesson. 2016. Alterations of

the volatile metabolome in mouse models of Alzheimer's disease.

Scientific Reports 6:19495. doi: 10.1038/srep19495. 

Kimball, B.A., S.A. Stelting, T.W. McAuliffe, R.S. Stahl, R.A.

Garcia, and W.C. Pitt. 2016. Development of artificial bait for

brown treesnake suppression. Biological Invasions 18:359-369.

doi: 10.1007/s10530-015-1031-z. 

Kimball, B.A., Opiekun, M., Yamazaki, K. and Beauchamp, G.K.

2014. Immunization alters body odor. Physiology and Behaviour.

128:80-85. doi: 10.1016/j.physbeh.2014.01.022 

Kimball, B.A., K. Yamazaki, D. Kohler, R.A. Bowen, J.P. Muth, M.

Opiekun, and G.K. Beauchamp. 2013. Avian influenza infection

alters fecal odor in mallards. PLoS ONE 8(10): e75411.

doi:10.1371/journal.pone.0075411

Major Research Accomplishments:

WS repellent research concludes that effective herbivore

repellent formulations must be applied directly to the food; and 2)

have physiological or evolutionary consequences for the

herbivore.

WS research identified unique “odor signatures” associated

with the feces of mallards infected with avian influenza virus.

Ongoing research with domestic ferrets has demonstrated that

trained animals can be used for surveillance of the virus in

waterfowl.

The chemical analysis paradigm developed by WS

researchers to address wildlife disease detection and surveillance

led to new discoveries in human health research regarding

biomarkers of Alzheimer's disease and traumatic brain injury.

WS researchers developed and tested a new brown treesnake

bait made of processed meat and an artificial mouse fat mixture.

Results showed the bait was eaten by snakes at rates similar to

the current bait and lasted longer under field conditions.

WS and James Madison University researchers discovered

that sex identity and pheromones released by a brown treesnake

are determined by the ratio of specific skin lipids in the snake.

Findings will aid in the development of pheromone-based tools for

brown treesnake management.