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United States Department of Agriculture

Agricultural Research Service

James R. Hagler

Research Entomologist


Pest Management & Biological Control Research Unit

USDA-ARS, Arid-Land Agricultural Research Center

 James Hagler in the Field  

James R. Hagler

Research Entomologist

Arid-Land Agricultural Research Center

21881 North Cardon Lane

Maricopa, Arizona, 85239


520-316-6330 (FAX)

B.S. Entomology,
New Mexico State University, 1983

M.S. Interdisciplinary (Entomology, Range Science, Statistics), New Mexico State University, 1985

Ph.D. Entomology, University of Arizona, 1988


Research Interests:

My areas of expertise include biological control, predator biology, and arthropod dispersal.  My current interests include: (1) characterizing and estimating the impact of arthropod predation on pests using molecular gut content assays (e.g., ELISA and PCR) and (2) developing protein marking immunoassays for studying insect dispersal.

Key Publications

Hagler, J. R. 2006. Development of an immunological technique for identifying multiple predator- prey interactions in a complex arthropod assemblage. Annals of Applied Biology In Press.


de Leon, J., V. Fournier, J. R. Hagler, and K. Daane. 2006. Development of molecular diagnostic markers for sharpshooters Homalodisca coagulata and Homalodisca liturata for use in predator gut content examinations. Entomologia Experimentails et Applicata 119:109-119.


Fournier, V., J. R. Hagler, K. Daane, J. de Leon, R. Groves, H. Costa, and T. J. Henneberry. 2006. Development and application of glassy-winged and smoke-tree sharpshooter egg-specific predator gut content ELISA. Biological Control 37: 108-118.


Jones, V.P., J.R. Hagler. J.F. Brunner, C.C. Baker, and T.D. Wilburn. 2006. An inexpensive immunomarking technique for studying movement patterns of naturally occurring insect populations.  Environmental Entomology (Forum) 35: 827-836.


Blackmer, J. L., J. R. Hagler, G. S. Simmons, and T. J. Henneberry. 2006. Dispersal of Homalodisca coagulata (Homoptera: Cicadellidae) in an architecturally complex host-plant matrix. Environmental Entomology In Press.


Hagler, J. R., and S. E. Naranjo. 2005. Use of a gut content ELISA to detect whitefly predator feeding activity after field exposure to different insecticide treatments. Biocontrol Science and Technology 15:321-339.


Kamita, S. G., Z. N. Do, A. I. Samra, J. R. Hagler, and B. D. Hammock. 2005. Characterization of cell lines developed from the glassy-winged sharpshooter, Homalodisca coagulata (Hemiptera: Cicadellidae). In Vitro Cell. Dev. Biol.--Animal 41:149-153.


Hagler, J. R., C. G. Jackson, R. Isaacs, and S. A. Machtley. 2004. Foraging behavior and prey interactions by a guild of predators on various lifestages of Bemisia tabaci. Journal of Insect Science 4:1-13, www/


Hagler, J. R., and S. E. Naranjo. 2004. A multiple ELISA system for simultaneously monitoring intercrop movement and feeding activity of mass-released predators. International Journal of Pest Management 50:199-207.


Hagler, J. R. 2004. Optimizing a protein-specific ELISA for detection of protein-marked insects. International Journal of Pest Management 50:209-214.


Blackmer, J. L., J. R. Hagler, G. S. Simmons, and L. A. Canas. 2004. Comparative dispersal of Homalodisca coagulata and Homalodisca liturata (Homoptera: Cicadellidae). Environmental Entomology 33:88-99.


Lavandero, B. I., S. D. Wratten, J. R. Hagler, and M. A. Jervis. 2004. The need for effective marking and tracking techniques for monitoring the movements of insect predators and parasitoids. International Journal of Pest Management 50:147-151.


Lavandero, B. I., S. D. Wratten, J. R. Hagler, and M. A. Jervis, editors. 2004. Effective marking and tracking techniques for monitoring natural enemy movements in pest management. Taylor & Francis, Abingdon.


Naranjo, S. E., P. C. Ellsworth, and J. R. Hagler. 2004. Conservation of natural enemies in cotton: Role of insect growth regulators in management of Bemisia tabaci. Biological Control 30:52-72.


Naranjo, S. E., J. R. Hagler, and P. C. Ellsworth. 2003. Improved conservation of natural enemies with selective management systems for Bemisia tabaci (Homoptera: Aleyrodidae) in cotton. Biocontrol Science and Technology 13:571-587.


Nelson, D. R., T. P. Freeman, J. S. Buckner, K. A. Hoelmer, C. G. Jackson, and J. R. Hagler. 2003. Characterization of the cuticular surface was pores and the waxy particles of the dustywing, Semidalis flinti (Neuroptera: Coniopterygidae). Comparitive Biochemisty and Physiology 136:343-356.


Hagler, J. R., S. A. Machtley, and J. E. Leggett. 2002. Parasitoid mark-release-recapture techniques: I. Development of a battery-operated suction trap for collecting minute insects. Biocontrol Science and Technology 12:653-659.


Hagler, J. R., C. G. Jackson, T. J. Henneberry, and J. R. Gould. 2002. Parasitoid mark-release-recapture techniques: II. Development and application of a protein marking technique for Eretmocerus spp., parasitoids of Bemisia argentifolii. Biocontrol Science and Technology 12:661-675.


Hagler, J. R. 2002. Foraging behavior, host stage selection and gut content analysis of field collected Drapetis nr. divergens: A predatory fly of Bemisia argentifolii. Southwestern Entomologist 27:241-249.


Hagler, J. R., and E. Miller. 2002. An alternative to conventional insect marking procedures: Detection of a protein mark on pink bollworm by ELISA. Entomologia Experimentails et Applicata 103:1-9.


Hagler, J. R., and C. G. Jackson. 2001. Methods for marking insects: Current techniques and future prospects. Annu. Rev. Entomol. 46:511-543.


Naranjo, S. E., and J. R. Hagler. 2001. Toward the quantification of predation with predator gut immunoassays: A new approach integrating functional response behavior. Biological Control 20:175-189.


DeGrandi-Hoffman, G., and J. R. Hagler. 2000. The flow of incoming nectar through a honey bee (Apis mellifera L.) colony as revealed by a protein marker. Insect Sociaux 47:302-306.


Hagler, J. R. 2000. Biological Control of Insects. Pages 207-241 in J. E. Rechcigl and N. A. Rechcigl, editors. Insect Pest Management: Techniques for Environmental Protection. Lewis Publishers, New York, NY.


Learn More About My Research

Mission Statement:

The WCRL's Predator Biology Unit is dedicated to the study of both fundamental and applied aspects of predator biology. We are using state-of-the-art molecular techniques to examine the natural enemies of the whitefly, pink bollworm and lygus. Our goals are to (1) identify indigenous predators of these key pests and (2) to evaluate the efficacy of augmentative biological control agents. Currently, we are examining differences in the feeding behavior between augmented (i.e., domestic) and indigenous predators of whitefly, pink bollworm and lygus.

Predator Mark-Release-Recapture Techniques

A key component in the evaluation of insect predation is the precise monitoring of the beneficials released. Generally, this has been done by marking insects. It is critical that the marker be environmentally safe, inexpensive, persistent, and without negative effect on insect behavior or health. Paint, dye, and tagging procedures are economical and easy to use, but are often ineffective on small insects because they can inhibit normal dispersal or require intensive labor. Elemental marking (i.e., rubidium) is environmentally safe and effective for some insects, but can adversely affect behavior and development of others. Furthermore, trace element marking is costly, generates chemical waste, requires specialized equipment, trained personnel, and extensive sample preparation. In summary, most of the current marking procedures proved to be too labor-intensive, impractical, or costly for my studies. I circumvented these obstacles by developing an insect immunomarking procedure that can be used to mark thousands of predators easily, rapidly, safely, and inexpensively for discrimination between commercially-reared predators and their native counterparts. The retention time of this marker is superior to many marking procedures. I have shown that it is feasible to mark predators with rabbit immunoglobulin G (IgG), a readily available mammalian blood serum protein, then run an ELISA using its complementary antibody (anti-rabbit IgG) while concurrently running ELISAs using the same samples against our pest MAbs to measure for the presence of multiple pest egg antigens (i.e., prey) in an individual predator's gut. In 1994 I field tested the immunomarker and found it to be superior to DayGlo dust marking. Individuals marked with DayGlo appeared "sluggish" while those marked with rabbit IgG showed no adverse effects. Another problem I encountered with DayGlo dust was that it was not visible to the naked eye 12 h after marking. Most of the individuals (>80%) I dusted had to be painstakingly examined under a dissecting microscope to determine if DayGlo was present. Therefore, examining individuals for the presence of DayGlo dust was more time consuming, expensive, and laborious than my marking immunoassay. However, the ultimate usefulness of any marker is that it is reliable. Again, my marking immunoassay proved to be more precise than the DayGlo dust marking procedure.

Given the success of our immunomarking ELISAs, I can now evaluate the feeding (using my gut content immunoassay) and dispersal behavior (using my marking immunoassay) of inundative releases of commercially-reared predators. Furthermore, the more recent discovery that protein marking works well for labeling minute arthropods has resulted in a significant paradigm shift in the way researchers now consider marking small parasitoids, predators, and herbivores for dispersal studies.

For more on our methods that we have developed for studying predation:
It's Gut-Check Time !!! Examining Insect Predators

Last Modified: 4/28/2008