Laboratory Exercise: Red Queen Card Game

HOW TO PLAY

The game is played in teams of two: one host, and one parasite. For teams of three: one person is the recorder. Feel free to occasionally switch roles, especially the recorder.

Get a pair of card decks (one blue and one red). Note your group number, which is written on the plastic bag containing the two decks.

Open the google docs spreadsheet “RQ cardgame_datasheet_template” at this url:

  1. Establish the starting population
  2. Shuffle the decks – blue for host and red for parasite
  3. Host and parasite each choose 12 cards from their deck. This becomes the host-parasite population. (Each card is an individual in the popl.)
  4. On the spreadsheet, select the tab with your Group Number.
  5. On your tab, record the number of cards of each suit(think of each suit as agenotype) for hosts and parasites. Record this data in “Counts” cells, generation 1.
  6. The total number of host cards should add to 12 under the Sum column (F). The total number of parasite cards should also add to 12 under the next Sum column (K). Make sure this is correct.
  1. Make contact
  2. Shuffle the host and parasite populations
  3. Randomly pairone host card withone parasite card, until 12 individual pairs have been made.
  4. Infection and selection
  5. If the host and parasite genotypes match, the parasite has made a successful infection. That parasite lives to reproduce. The host dies.If the host and parasite genotypes do not match, the parasite has been killed by the host. The host lives to reproduce.
  6. Reproduce
  7. Each living host makes two offspring and dies. Simulate this by adding 1 card of a matching genotype to each of your successful host cards.
  8. Each living parasite makes three offspring and dies. Simulate this by adding 2 cards for each matching parasite genotype to each of your successful parasite cards.
  9. Hosts: do you have too few cards of a given genotype (suit) to have every host of that genotype make matching offspring?If so then shuffle your main deck and randomly select additional cards (offspring) until you have 12 cards.You can think of this as mutation.
  1. Population size regulation
  2. Do you have too few offspring after reproduction? Host and parasite populations are each fixed at 12 individuals. Shuffle your main deck and randomly select additional offspring until you have 12. You can think of this as immigration.
  3. Do you have more than 12 offspring? Shuffle and randomly select 12 to make the next generation (see step 1). You can think of this as drift.

Return to step 1. Repeat 14x for a total of 15 generations.

Important Note: the last tab on the data sheet is called the “Metapopulation.” Metapopulationrefers to the population of populations. The tab calculates the genotype frequencies taken overall 12 populations for both the host and parasite. This then gives an idea of the genotypic diversity (measured by evenness) in the metapopulation. The metapopulation is also the source of immigrants into each of the subpopulations.

Short essay (5 points) to be written in class.

Compare the results for your population to the results in other populations. What are the general trends? Then compare the trends across the individual populations to the metapopulation. What did you observe in these comparisons? Write a short essay that briefly explains the patterns and your ideas (hypotheses) that explain the patterns. As part of your essay, please answer this question: Does host-parasite coevolution lead to the maintenance of genetic diversity? (Use both sides, if necessary.)