B.S. (University of Notre Dame, 1986)
M.S. (University of Maryland, 1992)
Ph.D. (University of Toronto, 2000)
My research in behavioral and evolutionary ecology focuses on how natural selection and sexual selection interact.
Specifically, I am interested in how natural selection on traits that are closely related to fitness (life history traits)
affects the strength of sexual selection and visa versa. For example, why is female-biased size dimorphism sometimes
explained in terms of natural selection for high female fecundity (e.g., insects, birds of prey) and other times explained
in terms of sexual selection on females (e.g., shorebirds)? Does one kind of selection predominate in some situations
and not in others? I use both lab and field experiments along with theory and computer simulations to explore how natural
and sexual selection interact. For example I have examined how natural selection during the postmating-prezygotic stage
of the life cycle affects mating behavior and speciation. I have used simulation models to examine how conspecific gamete
precendence (where conspecific sperm out-competes heterospecific sperm) can affect speciation rates. I am also currently
studying how social interactions affect both insect movement and mating behavior. Finally, I am developing an
experimimental system to test whether pervasive sex differences in genetic recombination rates on autosomes can be
explained by sexual selection.
Research:
Mormon Crickets: I am interested in the mating behavior of Mormon crickets (Anabrus simplex, Orthoptera: Tettigoniidae). These wingless
katydids reach extremely high density "outbreaks" and undergo mass migrations. In some environments they experience
reversals in typical sex-roles, so that females compete for mates and males are choosy. Since this reversal appears to
only take place in outbreak populations, I have begun to try to understand what regulates density and migratory behavior.
I am testing hypotheses about the relative importance of abiotic, biotic and social factors that regulate density and
migratory behavior in this katydid.
Speciation: My overarching interest in the interaction between sexual selection and natural selection has led me to study speciation.
In particular, some of my previous theoretical work suggested that condition dependent sexual selection can increase rates
of adaptation in traits under natural selection. This work has implications for speciation.
Sex differences in recombination rates: I am also currently testing hypotheses about the role of sexual selection in the evolution of sexual differences in
autosomal recombination rates. This work has both empirical and theoretical aspects. The evolution of sex differences in
recombination rates is a particularly interesting example of interaction between sexual and natural selection at the
molecular level. As part of this work I am beginning molecular genomic analyses comparing expression patterns for genes
involved in recombination in several species of Drosophila including Drosophila ananassae, where there is recombination
in both sexes.
Selected Publications:
Patrick D. Lorch and Maria R. Servedio. The evolution of conspecific gamete precedence and its
effect on reinforcement. Accepted for publication in Journal of Evolutionary Biology
Patrick D. Lorch, Luc Bussière and Darryl T. Gwynne. Quantifying the potential for sexual dimorphism using upper
the limits on Bateman slopes. Accepted for publication in Behaviour.
Stephen J. Simpson, Gregory A. Sword, Patrick D. Lorch. 2006. Cannibal crickets on a forced march for protein and
salt. Proceedings of the National Academy of Sciences of the United States of America. 103: 4152-4156.
Patrick D. Lorch, Gregory A. Sword, Darryl T. Gwynne and Gerald A. Andreson. 2005. Radiotelemetry reveals
differences in individual movement patterns between outbreak and non-outbreak Mormon cricket populations. Ecological
Entomology. 30: 548-555.
Patrick D. Lorch and Maria R. Servedio. 2005. Postmating-prezygotic isolation is not an important source of selection
for reinforcement within and between species in Drosophila pseudoobscura and D. persimilis. Evolution. 59(5): 1039-1045.
Patrick D. Lorch. 2005. Sex differences in recombination and mapping adaptations. Genetica. 123(1-2): 39-47.
(Also reprinted in The Genetics of Adaptation. 2005. Rodney Mauricio, editor. Kluwer, Dordrecht.)
Gregory A. Sword, Patrick D. Lorch and Darryl T. Gwynne. 2005. Migratory bands give crickets protection. Nature.
433: 703.
Patrick D. Lorch, Stephen Proulx, Locke Rowe and Troy Day. 2003. Condition dependent sexual selection
accelerates adaptation by natural selection. Evolutionary Ecology Research. 5(6): 867-881.
Patrick D. Lorch and Lin Chao. 2003. Selection for multiple mating in females due to mates that reduce female
fitness. Behavioral Ecology. 14(5): 679-686.
Patrick D. Lorch. 2002. Understanding reversals in the relative strength of sexual selection on males and
females: a role for sperm competition? American Naturalist. 159: 645-657.
Patrick D. Lorch and Darryl T. Gwynne. 2000. Radio telemetric evidence of migration in the gregarious
but not the solitary morph of the Mormon cricket (Anabrus simplex : Orthoptera: Tettigoniidae).
Naturwissenschaften. 87: 370-372.
Patrick D. Lorch and John McA. Eadie. 1999. The power of the concentrated-changes test for correlated evolution.
Systematic Biology. 48(1): 170-191.
Patrick D. Lorch, Gerald S. Wilkinson and Paul R. Reillo. 1993. Copulation duration and sperm precedence
in the stalk-eyed fly, Cyrtodiopsis whitei (Diptera: Diopsidae). Behavioral Ecology and Sociobiology.
32(5): 303-311.
Courses:
BiSc 152 - Animal Behavior (3). An evolutionary approach to the study of animal behavior, emphasizing behavioral ecology and sociobiology.
Students:
I encourage undergraduate and graduate students in my lab to work on either lab or field projects that might include
simulation models as a basis for sharpening intuition about the questions they are answering. Topics under the broad
umbrella of behavioral and evolutionary ecology might include measuring the strength of sexual selection in individuals
with different life history strategies (e.g. long and short winged morphs of one insect species). Another project might
involve building individual based simulation models of insect movement to test whether certain kinds of interaction
between individuals can mimic movement patterns seen in the field. Yet another project might be measuring the change in
recombination rates in males and females with and without sexual selection.
