title: Natural and experimental evolution of sexual conflict within Caenorhabditis nematodes.
abstract: BACKGROUND
  Although males and females need one another in order to reproduce, they often have different reproductive interests, which can lead to conflict between the sexes. The intensity and frequency of male-male competition for fertilization opportunities is thought to be an important contributor to this conflict. The nematode genus Caenorhabditis provides an opportunity to test this hypothesis because the frequency of males varies widely among species with different mating systems.
  
  
  RESULTS
  We find evidence that there is strong inter- and intra-sexual conflict within C. remanei, a dioecious species composed of equal frequencies of males and females. In particular, some C. remanei males greatly reduce female lifespan following mating, and their sperm have a strong competitive advantage over the sperm of other males. In contrast, our results suggest that both types of conflict have been greatly reduced within C. elegans, which is an androdioecious species that is composed of self-fertilizing hermaphrodites and rare males. Using experimental evolution in mutant C. elegans populations in which sperm production is blocked in hermaphrodites (effectively converting them to females), we find that the consequences of sexual conflict observed within C. remanei evolve rapidly within C. elegans populations experiencing high levels of male-male competition.
  
  
  CONCLUSIONS
  Together, these complementary data sets support the hypothesis that the intensity of intersexual conflict varies with the intensity of competition among males, and that male-induced collateral damage to mates can evolve very rapidly within populations.
authors.affiliation: Department of Biology, Bowdoin College, ME 04011, Brunswick, USA. mpalopol@bowdoin.edu.
authors.forename: Michael F
authors.initials: MF
authors.lastname: Palopoli
authors.affiliation: Institute of Ecology and Evolution, University of Oregon, OR 97403, Eugene, USA. colin.peden@gmail.com.
authors.forename: Colin
authors.initials: C
authors.lastname: Peden
authors.affiliation: Department of Biology, Bowdoin College, ME 04011, Brunswick, USA. caitlin.woo@gmail.com.
authors.forename: Caitlin
authors.initials: C
authors.lastname: Woo
authors.affiliation: Department of Biology, Bowdoin College, ME 04011, Brunswick, USA. kakiha@gmail.com.
authors.forename: Ken
authors.initials: K
authors.lastname: Akiha
authors.affiliation: Institute of Ecology and Evolution, University of Oregon, OR 97403, Eugene, USA. megan.ary@slane.k12.or.us.|Current address: South Lane School District, OR 97424, Cottage Grove, USA. megan.ary@slane.k12.or.us.
authors.forename: Megan
authors.initials: M
authors.lastname: Ary
authors.affiliation: Institute of Ecology and Evolution, University of Oregon, OR 97403, Eugene, USA. lo.cruze@gmail.com.|Current address: Department of Obstetrics and Gynecology, Medical University of South Carolina, SC 29412, Charleston, USA. lo.cruze@gmail.com.
authors.forename: Lori
authors.initials: L
authors.lastname: Cruze
authors.affiliation: Institute of Ecology and Evolution, University of Oregon, OR 97403, Eugene, USA. Jennifer.Anderson@rennes.inra.fr.|Current address: INRA, UR1037 LPGP, Campus de Beaulieu, F-35000, Rennes, France. Jennifer.Anderson@rennes.inra.fr.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Anderson
authors.affiliation: Institute of Ecology and Evolution, University of Oregon, OR 97403, Eugene, USA. pphil@uoregon.edu.
authors.forename: Patrick C
authors.initials: PC
authors.lastname: Phillips
mesh_terms: D000818:Animals; D005075:Biological Evolution; D002107:Caenorhabditis / Q000235:genetics* / Q000502:physiology; D005260:Female; D008297:Male; D012098:Reproduction; D057945:Self-Fertilization; D012726:Sexual Behavior, Animal; D013094:Spermatozoa