The University of Arizona
brown colorbar
Department of Entomology
turqoise colorbar
Home •   People  •   Research  •  News & Events  •  Graduate Programs  •  Insect ID  •   Outreach

Entomology: S. Patricia Stock


1992: Ph.D. Natural Sciences (Parasitology), National University of La Plata, Argentina.
1985: BS, Zoology, University of La Plata, Argentina.

Visit Patricia Stock's website

Research Interests: Insect pathogens as model systems. Nematode-bacteria symbioses. Multitrophic interactions. Entomopathogens and pest management.

My research program focuses on the study of insect pathogens as model systems. We study entomopathogenic nematodes (aka EPN) Steinernema and Heterorhabditis spp. (Nematoda: Steinernematidae, Heterorhabditidae) and their bacterial symbiont bacteria Xenorhabdus and Photorhabdus spp (Enterobacteriaceae) which represent an emerging model of terrestrial animal-microbe symbiotic relationships. Questions regarding the mutualism between Steinernema and Xenorhabdus surround many issues: How this association is maintained and transmitted through generations? What beneficial functions each partner provides to the other? How partner specificity is maintained?
EPN symbiotic bacteria also represent a new and rich source of novel bioactive molecules with insecticidal, nematicidal, antibiotic, and antimycotic properties. In this respect, my laboratory is involved in the discovery and characterization secondary metabolites of a newly discovered Photorhabdus bacteria that are native to SW USA.

Another newly developed area in my research program focuses on the consideration of mutualists as suitable models for understanding trophic complexities and interactions in food webs. Until now, the study of insect pathogen-plant interactions has focused on how the plant (usually a crop) affects the success of the pathogen as a biological control agent.

A continued research focus is nematode biodiversity. My laboratory is actively engaged in survey and inventory projects in different geographic regions of the world We are currently investigating EPN diversity in oak woodlands of southeastern Arizona Sky-Islands. In Arizona, the diversity of oak species is broad, but with a fragmented distribution mainly confined to higher elevations (4,500-7,500 ft.). The particular distribution of oak woodlands in southeastern Arizona provides an interesting framework for studying population structure of nematodes associated with these habitats, as well as the evolutionary and ecological forces that contribute to their diversification.

My involvement in these biotic surveys and inventory projects provides me dual benefit. Not only I have the opportunity to discover and describe new taxa, but I also consider this novel source of nematodes in applied research such as their implementation in biological control or integrated pest management of insect pests. In this respect, I have an active research program on insect pathology and the use of EPN as biological control agents. The overall objectives of this program are to develop entomopathogens as effective biological control agents against major agricultural and urban pests, and to develop a basic understanding of their ecology and behavior.

Teaching Responsibilities:

Every other spring semester: ENTO 446/EIS 546 - Insect Pathogens
Every fall semester: ENTO/ECOL/MIC/ VSC 310 - Living in Symbiosis

Selected Publications (last 5 years):

Orozco, R. A., Hill, T. and Stock, S. P. 2012. Characterization and phylogenetic relationships of Photorhabdus luminescens subsp. sonorensis (Proteobacteria: Enterobacteriaceae) the bacterial symbiont of the entomopathogenic nematode Heterorhabditis sonorensis (Nematoda: Heterorhabditidae). Current Microbiology (In Press)

Miranda, V. A., Davidowitz, G., Bronstein, J. and Stock, S. P. 2012. The effect of insect host age and diet on the fitness of the entomopathogenic nematode- bacteria complex. J. Invert. Pathol. (In Press).

Dillman, A., Chaston, J. M. Adams, B. J. Ciche, T. A. Goodrich-Blair, H., Stock. S. P. And Sternberg, P. 2012. An entomopathogenic nematode by any other name. PLOS Pathogen. 8

Gassmann, A. J., E. Hannon, Sisterson, M. Carriere, Y, Tabashnik, B. E. and Stock, S. P. 2012. Effects of entomopathogenic nematodes on evolution of pink bollworm resistance to Bacillus thuringiensis Toxin Cry1Ac. J. Econom. Entomol. 105: 994-1005.

Kim, S. K. Flores-Lara, Y and Stock, S. P. 2012. Morphology and ultrastructure of the bacterial receptacle in Steinernema nematodes (Nematoda: Steinernematidae). J. Invert. Pathol. 110: 366-374.

Stock, S. P. Lee, M. M. and Flores-Lara, Y. 2012. The rectal glands of Heterorhabditis bacteriophora (Rhabditida: Heterorhabditidae) hermaphrodites and their role in symbiont transmission. J. Invert. Pathol. 101: 135-138.

Kaminga,K.L. Davis, J. A., Stock, S P. and Richter, A. R. 2011. First Report of a Mermithid Nematode Infecting Piezodorus guildinii and Acrosternum hilare (Hemiptera: Pentatomidae) in the United States. The Florida Entomologist. 94: 890-894.

Stock, S. P., Bird, D., Ghedin, E. and Goodrich-Blair, Heidi. 2011. Abstracts of NEMASYM: The Third Nematode-Bacteria Symbioses Research Coordination Network Meeting. Symbiosis. 55: 1-13

Sugar, D. R. , Murfin, K. E., Chaston, J. M., Andersen, A. W., Richards, G. R., deLéon, L., Baum, J. A., Clinton, W. P. , Forst, S., Goldman, B. S. , Krasomil-Osterfeld, K. C., Slater, S., Stock, S. P. and Goodrich-Blair, H. 2011.Phenotypic variation and host interactions of Xenorhabdus bovienii SS 2004, the entomopathogenic symbiont of Steinernema jollieti nematodes. Env. Microbiol.DOI: 10.1111/j.1462-2920.2011.02663.x.

Lee, M. M. and Stock, S. P. 2010. A multigene approach for assessing evolutionary relationships of Xenorhabdus spp. (Proteobacteria), the bacterial symbionts of entomopathogenic Steinernema nematodes. Journal of Invertebrate Pathology 104, 67-74.

Lee, M. M. and Stock, S. P. 2010. Multilocus approach to assessing coevolutionary relationships between Steinernema nematodes (Nematoda: Steinernematidae) and their bacterial symbionts, Xenorhabdus spp (Proteobacteria, Enterobacteriaceae). Systematic Parasitology 77, 1-12.

Stock, S. P., Selossé, M.A., Bordenstein, S., Odden, J., Oldenberg, D., Reznikoff, W. and Werren, J. H. 2010. Symbiosis instruction: considerations from the education workshop at the 6th ISS Congress. Symbiosis 51, 67-73.

Gassmann, A. J. Stock, S. P., Tabashnik, B. E. and Singer, M. J. 2010. Tritrophic effects of host plants on an herbivore-pathogen interaction. Annals of the Entomological Society of America 103, 371-378.

Hannon, E. R., Sisterson, M. S., Stock, S. P., Carrière, Y., Tabashnik, B. E. and Gassmann, A. J. 2010. Effects of four nematode species on fitness costs of pink bollworm resistance to Bacillus thuringiensis toxin Cry1Ac. Journal of Economic Entomology 103, 1821-1831.

Plichta, K. C., Joyce, S., Waterfield, N., Clarke, D. and Stock S. P. 2009. Heterorhabditis gerrardi n. sp. (Nematoda: Heterorhabditidae): the hidden host of Photorhabdus asymbiotica (Enterobacteriaceae: Gamma-Proteobacteria. Journal of Helminthology 83, 309-320.

Hatting, J., Stock, S. P. and Hazir, S. 2009. Diversity and distribution of entomopathogenic nematodes (Steinernematidae, Heterorhabditidae) in South Africa. Journal of Invertebrate Pathology 102,120-128.

Powers, T.O., Neher, D.A., Mullin, P. Esquivel, A., Giblin-Davis, R.M., Kanzaki, N., Stock, S. P., Mora, M. M. and Uribe-Lorio, L. 2009. Tropical nematode diversity: vertical stratification of nematode communities in a Costa Rican humid lowland rainforest. Molecular Ecology 18, 985-996.

Stock, S. P., Rivera-Orduño, B. and Flores-Lara, Y. 2009. Heterorhabditis sonorensis n. sp. (Nematoda: Heterorhabditidae), a natural pathogen of the seasonal cicada Diceroprocta ornea (Homoptera: Cicadidae in the Sonoran desert. Journal of Invertebrate Pathology 100, 175-184.

Gassmann A. J., Fabrick, J.A., Sisterson, M. Hannon, E.R., Stock, S. P., Carrière, Y and Tabashnik, B.E. 2009. Effects of pink bollworm resistance to Bacillus thuringiensis on phenoloxidase activity and susceptibility to entomopathogenic nematodes. Journal of Economic Entomology 102, 1224-1232.

Lee, M. M., Sicard, M., Skeie, M, and Stock, S. P. 2009. Steinernema boemarei n. sp. (Nematoda: Steinernematidae), a new entomopathogenic nematode from southern France. Systematic Parasitology 72, 127-141.

Xu, Y., Orozco, R., Kithsiri, E.M., Espinosa-Artiles, P. Gunatilaka L., Stock, S. P., and Molnár, I. 2009. Biosynthesis of the cyclooligomer depsipeptide bassianolide, an insecticidal virulence factor of Beauveria bassiana. Fungal Genetics and Biology 46, 353-364.

Gassmann, A., Stock, S. P., Sisterson, M. S., Carrière, Y., and Tabashnik, B. E. 2008. Synergism between entomopathogenic nematodes and Bt crops: integrating biological control and resistance management. Journal of Applied Ecology 45, 957-966.

Yu, H., Gouge, D. H., Stock, S. P. and Baker, P. B. 2008. Development of entomopathogenic nematodes (Rhabditida: Steinernematidae; Heterorhabditidae) in desert subterranean termite Heterotermes aureus (Isoptera: Rhinotermitidae). Journal of Nematology 40, 311-317.

Stock, S. P., Al Banna, L., Katbeh, A. and Darwish, R. 2008. Diversity and distribution of entomopathogenic nematodes (Nematoda: Steinernematidae, Heterorhabditidae) and their bacterial symbionts (Gamma-Proteobacteria: Enterobacteriaceae) in Jordan. Journal of Invertebrate Pathology 98, 228-234.

Lopez Nunez, J.C., Plichta, K., Gongora-Botero, C. and Stock, S. P. 2008. A new entomopathogenic nematode, Steinernema colombiense n. sp. (Nematoda: Steinernematidae) from Colombia. Nematology 10, 561-574.

Stock, S. P. and Goodrich-Blair, H. 2008. Entomopathogenic nematodes and their bacterial symbionts: the inside out of a mutualistic association. Symbiosis 46, 65-76.

Stock, S. P. and Goodrich-Blair, H. 2008. Nematode-bacterium symbioses: crossing kingdom and disciplinary boundaries. Symbiosis 46, 61-64.

Emelianoff, V., Le Brun, N., Pagès, Stock, S. P., Tailliez, P., Moulia, C. and Sicard, M. 2008. Isolation and identification of entomopathogenic nematodes and their symbiotic bacteria from Hérault and Gard (Southern France). Journal of Invertebrate Pathology 98, 211-217.

Xu, Y., Orozco, R., Kithsri-Wijeratne, E.M., Gunatilaka, A.A., Stock, S. P. and Molnar, I. 2008. Biosynthesis of the cyclooligomer depsipeptide beauvericin, a virulence factor of the entomopathogenic fungus Beauveria bassiana. Chemistry and Biology 15, 898-907.

Uribe-Lorio, L., Mora, M. and Stock, S. P. 2007. Steinernema costaricense n. sp. and Steinernema puntauvense n.sp. (Rhabditida, Steinernematidae), two new entomopathogenic nematodes from Costa Rica. Systematic Parasitology 68, 167-172.

Simard, L., Belair, G., Stock, S. P., Mauleon, H. and Dionne, J. 2007. Natural occurrence of entomopathogenic (Rhabditidae, Steinernematidae) on golf courses in eastern Canada. Nematology 9, 325-332.

Lopez-Nuñez, J. C., Cano, L., Gongora-Botero, C. E. and Stock, S. P. 2007. Diversity and evolutionary relationships of entomopathogenic nematodes (Steinernematidae and Heterorhabditidae) from the central Andean region of Colombia. Nematology 9, 333-341.

Flores-Lara, Y., Renneckar, D., Forst, S., Goodrich-Blair, H., and Stock, S. P. 2007. Influence of nematode age and culture conditions on morphological and physiological parameters in the bacterial receptacle of Steinernema carpocapsae (Nematoda, Steinernematidae). Journal of Invertebrate Pathology 95, 110-118.

Department of Entomology at the University of Arizona
Forbes 410, PO Box 210036, Tucson, AZ 85721-0036
Phone: (520) 621-1151 • Fax: (520) 621-1150 • E-mail:

turqoise colorbar
College of Agriculture & Life Sciences Arizona Cooperative Extension