February 1, 2015
College of Computer, Mathematical, and Natural Sciences

Pedro Barbosa


Emeritus Professor


Email: pbarbosa@umd.edu
Office Phone: 301-405-3946
Fax: 301-314-9290
Office Address: University of Maryland * Entomology Department * 4112 Plant Sciences
Building * University of Maryland * College Park, MD 20742
URL: http://www.barbosalab.umd.edu/

Lab Activities

Because I am no longer taking on new students, lab personnel consist of visiting faculty and post-doctoral fellows, and, periodically, undergraduate students doing internships.

Graduate Program Affiliations

  • BISI - BISI-Behavior, Ecology, Evolution, & Systematics (BEES) and Entomology

Research Interests

My interests are in theoretical and applied aspects of insect-plant interactions: in particular interactions referred to as tri-trophic level interactions. Recent projects in the lab have involved research to determine how plants influence parasitoid-host, predator-prey and insect-plant interactions. These studies are approached from behavioral, genetic, population, and community ecological perspectives.

My most recent interests lie in the evaluation of hypotheses on Associational Resistance and Associational Susceptibility in agroecosystems. In addition, I am interested in macrolepidopteran immune responses to parasitoids and its potential role as a mechanism explaining host plant-associated differences in the effectiveness of natural enemies. These insights may be useful in testing current theories and generating new hypotheses relating to the ecology of low density (scarce) insect herbivores and the population dynamics of agricultural pests.  

I am also interested in assessing the extent of genetic divergence among herbivore subpopulations, and the range and magnitude of movement of both herbivores and parasitoids. In this research I will compare gene flow (as a proxy for individual dispersal) among closely related species that differ in host specificity.

Recent Publications

  • Mallampalli, N., Gould, F. and Barbosa, P. 2005. Predation of Colorado potato beetle eggs by a polyphagous ladybeetle in the presence of alternate prey: potential impact on resistance evolution. Entomol. Exp. Appl.. 114: 47-55.
  • Stireman, III, J. O., Dyer, L. A., Janzen, D. H., Singer, M. S., Lill, J. T., Marquis, R. J., Ricklefs, R. E., Gentry, G. L., Hallwachs, W., Coley, P. D., Barone, J. A., Greeney, H. F. Connahs, H., Barbosa, P., Morais, H. C., and Diniz, I. R. 2005. Climatic unpredictability and parasitism of caterpillars: implications of global warming. Proc. Natl. Acad. Sci. 102: 1738417387.
  • Medina, R. F., Barbosa, P., and Waddell, K. 2005. Parasitism levels in Orgyia leucostigma (J. E. Smith) (Lepidoptera: Lymantriidae) feeding on two tree species: implications for the slow growth-high mortality hypothesis. Entomol. Exp. Appl. 115: 193197.
  • Barbosa, P. and Castellanos, I. 2005. The Ecology of Predator-Prey Interactions. Oxford University Press.
  • Barbosa, P., Caldas, A., and Riechert, S. E. 2005. Constraints and Opportunities in the Assemblage Control Hypothesis. In: The Ecology of Predator-Prey Interactions. Barbosa, P. and Castellanos, I. (eds.). pp. 344-369. Oxford University Press.
  • Castellanos, I. and Barbosa, P. 2006. Evaluation of predation risk by a caterpillar using substrate-borne vibrations. Anim. Behav. 72: 461-469.
  • Gentry, G. L. and Barbosa, P. 2006. Effects of leaf epicuticular wax on the movement, foraging behavior, and attack efficacy of Diaeretiella rapae. Entomol. Exp. Appl. 121:115-122.
  • Medina, R. F., Barbosa, P., Christman, M., and Battisti, A. 2006. Number of individuals and molecular markers to use in genetic differentiation studies. Mol. Ecol. Notes 6:10101013.
  • Guthrie, J. T., Wigfield, A. W. Humenick, N. M., Perencevich, K., Taboada, A., and Barbosa, P. 2006. Influences of stimulating tasks on reading motivation and comprehension. J. Educ. Res. 99: 232-245.
  • Barbosa, P. and Caldas, A. 2007. Do larvae of species in macrolepidopteran assemblages share traits that influence susceptibility to parasitism? Environ. Entomol. 36: 329-336.
  • Barbosa, P. and Caldas, A. 2007. Seasonal patterns of parasitism and differential susceptibility among species in macrolepidopteran assemblages on Salix nigra (Marsh) and Acer negundo L. Ecol. Entomol. 32:1-7.
  • Barbosa, P., Caldas, A. and Godfray, H. C. J. 2007. Comparative food web structure of larval macrolepidoptera and their parasitoids on two riparian tree species. Ecol. Res. 22:756-766.
  • Wigfield, A., Guthrie, J. T., Perencevich, K. C., Taboada, A., Klauda, S. L., McRae, A. and Barbosa, 2008. P. The Role of Reading Engagement in Mediating the Effects of Instruction on Reading Outcomes. Psychology in the Schools (In Press).
  • Barbosa, P., Hines, J., Kaplan, I., Martinson, H., Szczepaniec, A. and Szendrei, Z. 2009. Associational resistance and associational susceptibility: having right or wrong neighbors. Annu. Rev Ecol. Evol. Syst. (Accepted for Publication).
  • Moreno, C. R., Lewins, S. A. and Barbosa, P. 2010. Influence of relative abundance and taxonomic identity on the effectiveness of generalist predators as biological agents. Biological Control 52:96-103. [Article]
  • Castellanos, I., Barbosa, P., Zuria, I., and Caldas, A. 2010. Does the mimetic posture of Macaria aemulataria (Walker) (Geometridae) larvae enhance survival against bird predation? J. Lepidopterists’ Soc. 64:113–115.
  • Lind, E. M. and Barbosa, P. 2010. Life history traits predict relative abundance in an assemblage of forest caterpillars. Ecology 91:3274-3283. Selected by the Faculty of 1000 (F1000) service (which identifies and evaluates the most important articles in biology and medical research publications). [Article]
  • Lind, E. M. and Barbosa, P. 2010. High beta diversity between trees drives landscape-level homogeneity of a temperate forest caterpillar assemblage. Ecography  (Submitted) [Article]
  • Castellanos, I., Barbosa, P., Zuria, I., Tammaru, T. and Christman, M. 2011. Contact with caterpillar hairs triggers predator-specific defensive responses. Behavioral Ecology (in press). [Article]
  • Castellanos, I. and Barbosa, P. 2011. Costs of dropping from host-plants in response to predators by polyphagous caterpillars. J. Lepidopterists Soc. 65:270-272.


  • Research Award, University of Maryland, Collegeof Chemical & Life Sciences, 2007
  • Honorary Member, Entomological Society of America.(2006)
  • Selected, Fellow of the Entomological Society of America (1997)
  • Fellow, American Association for the Advancement of Science, Elected (1991)
  • Distinguished Research Faculty Fellowship, University of Maryland (1991)
  • President (1987), Entomological Society of America, Eastern Branch
  • President (1987-1989), Association for Puerto Ricans in Science and Engineering
  • Bussart Memorial Award for Excellence in Research. Entomological Society of America; Eastern Branch (1986 and 1987)
  • Ford Foundation Fellow; National Research Council Fellowship (1984)
  • Visiting Professor: Zhejiang Agricultural University (1984-1987)
  • Professor Ad Honorium (Adjunct Professor), University of Puerto Rico (Mayaquez Campus, 1984)


  • B.S. 1966, City College of New York, Biology
  • M.S. 1969, Univ. of Massachusetts, Entomology
  • Ph.D. 1971, Univ. of Massachusetts, Entomology