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United States Department of Agriculture

Agricultural Research Service

Theresa Pitts Singer

Research Entomologist

Educational Background

B.A.s - General Biology and Anthropology, Vanderbilt University, 1985
M.S. - Entomology, University of Georgia, 1989
Ph.D. – Entomology, University of Georgia, 1996

Research Interests

My research focuses on improving the commercial-scale use and management of the alfalfa leafcutting bee (Megachile rotundata), a pollinator of alfalfa, canola, and other crops.  I also work on improving the management of the blue orchard bee (Osmia lignaria), which has recently gained attention due to a shortage of honey bees for fruit pollination.  Both of these bees are solitary, but will nest in large aggregations in artificial nest cavities provided by bee managers in the field.  With the cooperation of regional alfalfa seed growers, I have been examining aspects of alfalfa leafcutting bee management throughout the year to determine the primary causes of mortality and loss of bees for pollination.  Field and laboratory trials are used to follow-up on suspected causes of management and mortality problems.  For example, I study the impact of the density of bees released in commercial fields on the amount of seed produced and the success of bee reproduction.  I am also looking to better define and find exact causes of “pollen balls,” which are bee cells seen on x-ray to contain unused larval provisions but no obvious larvae.  In order to improve retention of leafcutting bees and blue orchard bees in the field, I study nesting behavior due to chemical cues in the bees’ environment, especially in chemicals in the nest.  Bee behavior is studied in the field and in the laboratory, and gas chromatography is used to verify specific chemicals that influence behavior.

Other studies in my work group are performed to determine how chemicals in the nest influence a female bee’s ability to locate a cavity for nest initiation, or to recognize her own nest among hundreds or thousands of others.  Specific research goals include: determining if the bees are able to learn nesting cues and if so, when the cues are learned during bee development; revealing nest-marking behavior and the presence of chemical cues within the nest used for nest recognition; and determining the source of chemical cues in the nest through chemical and microscopic analyses.  Results of such studies may lead to the ability to train commercial bees to novel odors that can be used to improve nesting and retention of bees at artificial nest sites.


Last Modified: 4/17/2009