Bug Hunters Speeds
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VERSION
$Id: Bug Hunters Speeds.nlogo 37721 2008-02-05 02:11:31Z michelle $
WHAT IS IT?
This is a HubNet activity of natural/artificial selection model that shows the result of two competing forces on natural selection of the speed of prey. Which force dominates depends on the behavior of predators.
One force is that predators that chase prey, tend to catch slower moving prey more often, thereby selecting for prey that are faster over many generations of offspring.
Another force is that predators who wait for their prey without moving, tend to catch prey that are moving faster more often, thereby selecting for prey that are slower over many generations of offspring.
By also adjusting whether bugs try to avoid the predator and the predictability of their motion, a different one of these competing forces will tend to dominate the selective pressure on the population.
HOW IT WORKS
Each HubNet participant or player assumes the role of a predator. When the HubNet simulation is started after pressing GO, participants should try to click on bugs as fast as they can with the mouse.
Each participant can monitor his or her relative success compared to other participants by watching the monitors in the client that show the TOP HUNTER (the person with most catches), how many that person caught (TOP HUNTER'S CATCHES) and the RELATIVE % they have caught compared to the best hunter (e.g. if the player has caught 40 and the best hunter has caught 80, then s/he has 50%).
Press SETUP to create a population of bugs, determined by six times the INITIAL-BUGS-EACH-SPEED slider. These bugs that are created are randomly distributed around the world and assigned a speed.
When you press GO the bugs begin to move at their designated speeds. As they move around, try to eat as many bugs as fast as you can by clicking on them. Alternatively, you may hold the mouse button down and move the predator over the bugs.
The six different speeds that a bug might move at are distributed amongst six different sub-populations of the bugs. These speeds are inherited. With each bug you eat, a new bug is randomly chosen from the population to produce one offspring. The offspring is an exact duplicate of the parent (in its speed and location). The creation of new offspring keeps the overall population of the bugs constant.
Initially there are equal numbers of each sub-population of bug (e.g. ten bugs at each of the 6 speeds). Over time, however, as you eat bugs, the distribution of the bugs will change as shown in the "Number of bugs" histogram. In the histogram, you might see the distribution shift to the left (showing that more slow bugs are surviving) or to the right (showing that more fast bugs are surviving). Sometimes one sub-population of a single speed of bug will be exterminated. At this point, no other bugs of this speed can be created in the population.
HOW TO USE IT
To run the activity press the GO button. To start the activity over with the same group of students stop the GO button by pressing it again, press the SETUP button, and press GO again. To run the activity with a new group of students press the RESET button in the Control Center.
Make sure you selecv Mirror 2D view on clients in the HubNet Control Center after you press SETUP.
INITIAL-NUMBER-BUGS-EACH-SPEED is the number of bugs you start with in each of the six sub-populations. The overall population of bugs is determined by multiplying this value by 6.
SPEED-COLOR-MAP settings help you apply or remove color visualization to the speed of the bugs:
- The "all green" setting does not show a different color for each bug based on its speed". Keeping the color settings switched to something besides "all green" can tend to result in the predator (the user) unconsciously selecting bugs based on color instead of speed.
- The "rainbow" setting shows 6 distinct colors for the 6 different speeds a bug might have. These color settings correspond to the plot pen colors in the graphs.
- The "purple shades" setting shows a gradient of dark purple to light purple for slow to fast bug speed.
NUMBER OF BUGS is a histogram showing the distribution of bugs at different speeds.
BUGS CAUGHT is a histogram showing the historical record of the distribution of bugs caught at different speeds.
WIGGLE?, when set to "on" adds a small amount of random twist in the motion of the bugs as they move forward each time step.
FLEE?, when set to "on" has bugs turn around (to face in the opposite direction) when they detect your mouse click (as a predator) in their detection cone (an arc of 120 degrees that has a range of 2 units). Bugs can detect the predator only in this arc in front of them, and so will not react when caught from behind.
THINGS TO NOTICE
The CURRENT BUGS histogram tends to shift right (increasing average speed) if you assume the role of chasing easy prey.
The CURRENT BUGS histogram tends to shift left (decreasing average speed) if you assume the role of waiting for prey come to you. The same effect can also be achieved by moving the predator around the world randomly.
THINGS TO TRY
Set the model up with INITIAL-BUGS-EACH-SPEED set to one. Slow the model down and watch where new bugs come from when you eat (click mouse on) a bug. You should see a new bug hatch from one of the five remaining and it should be moving at the same speed as its parent.
Wait in one location for the bugs to come to you by placing the cursor in one location and holding down the mouse button. All bugs that run into you will be eaten.
Chase bugs around trying to catch the bug nearest you at any one time by holding the mouse button down and moving the cursor around the view after the nearest bug.
EXTENDING THE MODEL
The Bug Hunt Speeds model has bugs move in a straight line. It would be more difficult if bugs wandered in a path that is not a straight line and if the bugs avoided you (the predator). Both of these characteristics as well as speed are inheritable characteristics in the Bug Hunt Scurry model.
A HubNet version of the model with adjustable starting populations of bugs would help show what happens when two or more competitors assume similar vs. different hunting strategies on the same population at the same time.
RELATED MODELS
Bug Hunt Speeds
Bug Hunt Camouflage
Bug Hunters Camouflage
Peppered bugs
Guppy Spots
CREDITS AND REFERENCES
Inspired by EvoDots software:
http://faculty.washington.edu/~herronjc/SoftwareFolder/EvoDots.html
Comments and Questions
globals [ total-caught ;; keeps track of total number of bugs caught total-speed-6-caught ;; keeps track of the number of bugs caught with speed of 6 total-speed-5-caught ;; keeps track of the number of bugs caught with speed of 5 total-speed-4-caught ;; keeps track of the number of bugs caught with speed of 4 total-speed-3-caught ;; keeps track of the number of bugs caught with speed of 3 total-speed-2-caught ;; keeps track of the number of bugs caught with speed of 2 total-speed-1-caught ;; keeps track of the number of bugs caught with speed of 1 time ;; keeps track of number of simulation steps that have passed old-color-map ;; keeps track of the previous value of the SPEED-COLOR-MAP chooser histogram-interval-size ;; the value of the interval size for each bar of the histogram leader leader-caught number-players last-ticks ;; what the the tick value was at the start of the ;; current interval bugs-in-a-batch ;; how many bugs must be caught in a batch. when this is reached, ;; the time to reach this (the interval) is recorded interval-length ;; how long it took to catch the last number of bugs-in-a-batch caught-in-current-batch ;; how many bugs have been caught so far in this current interval batches ;; how many batches have been caught (for plotting) adult-age ;; the age at which recently hatched bugs become full sized ] breed [ players player ] breed [bugs bug] bugs-own [speed] players-own [ user-name caught attempts percent ] to startup hubnet-set-client-interface "COMPUTER" [] hubnet-reset set number-players 0 setup-clear end to setup-clear ca setup end to setup cp clear-all-plots reset-ticks set total-caught 0 set total-speed-6-caught 0 set total-speed-5-caught 0 set total-speed-4-caught 0 set total-speed-3-caught 0 set total-speed-2-caught 0 set total-speed-1-caught 0 set leader "" set leader-caught 0 set bugs-in-a-batch 10 ;; ten bugs must be caught to make a batch set caught-in-current-batch 0 ;; no bugs are currently caught in the first batch set interval-length 0 ;; previous interval-length value is 0 by default set batches 0 ;; no batches caught yet set time 0 set histogram-interval-size 1 set old-color-map speed-color-map ;; holds the starting value of the chooser ask patches [ set pcolor white ] ;; white background make-initial-bugs ask players [ initialize-player ] update-plots end to make-initial-bugs ask bugs [die] create-bugs initial-bugs-each-speed [ set speed 1 ] create-bugs initial-bugs-each-speed [ set speed 2 ] create-bugs initial-bugs-each-speed [ set speed 3 ] create-bugs initial-bugs-each-speed [ set speed 4 ] create-bugs initial-bugs-each-speed [ set speed 5 ] create-bugs initial-bugs-each-speed [ set speed 6 ] ask bugs [ set shape "bug" setxy random-xcor random-ycor ] ask bugs [ set-color ] end ;;;;;;;;;;;;;;;;;;;;; ;; Runtime Procedures ;;;;;;;;;;;;;;;;;;;;; to go every 0.04 [ listen-clients move-bugs ask bugs [set-color] ;; advance the clock tick if ticks mod 10 = 0 [ update-plots ] ] end to move-bugs ;; the speed factor is a scaling number used to adjust the amount all the bugs move ;; for example a speed-factor of 2, scales the speed of all the bugs so they are moving twice as fast ;; it is a useful slider to change for slower and faster computers, that might have the bugs ;; as a whole population moving too fast or too slow across the screen ask bugs [ fd (speed * 0.06) ] end ;; keep a stable population of bugs as predation rates go up or down to check-caught ;; extract the coords from the hubnet message let clicked-xcor (item 0 hubnet-message) let clicked-ycor (item 1 hubnet-message) ask players with [ user-name = hubnet-message-source ] [ set xcor clicked-xcor set ycor clicked-ycor ;; go to the location of the click set attempts attempts + 1 ;; each mouse click is recorded as as an attempt ;; for that player ;; if the players clicks close enough to a bug's location, they catch it ;; the in-radius (bug-size / 2) calculation helps make sure the user catches the bug ;; if they click within one shape radius (approximately since the shape of the bug isn't ;; a perfect circle, even if the size of the bug is other than 1) if any? bugs in-radius (bug-size / 2) [ let doomed-bug one-of bugs in-radius (bug-size / 2) let speed-of-caught 0 ask doomed-bug [set speed-of-caught speed if (speed-of-caught = 6) [ set total-speed-6-caught (total-speed-6-caught + 1) ] if (speed-of-caught = 5) [ set total-speed-5-caught (total-speed-5-caught + 1) ] if (speed-of-caught = 4) [ set total-speed-4-caught (total-speed-4-caught + 1) ] if (speed-of-caught = 3) [ set total-speed-3-caught (total-speed-3-caught + 1) ] if (speed-of-caught = 2) [ set total-speed-2-caught (total-speed-2-caught + 1) ] if (speed-of-caught = 1) [ set total-speed-1-caught (total-speed-1-caught + 1) ] die ] set caught caught + 1 set total-caught total-caught + 1 ;; replace the eaten bug with a random offspring from the remaining population ask one-of bugs [ hatch 1 [ rt random 360 ] ] ] ] end ;;;;;;;;;;;;;;;;;;;;; ;; Visualization Procedures ;;;;;;;;;;;;;;;;;;;;; to set-color ;; turtle procedure if speed-color-map = "all green" [ set color green ] if speed-color-map = "violet shades" [ set color violet - 4 + speed ] if speed-color-map = "rainbow" [ set color item (speed - 1) [violet blue green brown orange red] ] end ;;;;;;;;;;;;;;;;;;;;;; ;; HubNet Procedures ;;;;;;;;;;;;;;;;;;;;;; to add-player set number-players number-players + 1 create-players 1 [ set user-name hubnet-message-source initialize-player ] end to initialize-player set attempts 0 set caught 0 set hidden? true set-percent send-student-info end to remove-player set number-players (number-players - 1) ask players with [ user-name = hubnet-message-source ] [ die ] end to set-percent ifelse leader-caught > 0 [ set percent ((caught / leader-caught) * 100)] [ set percent 0 ] end to send-student-info hubnet-send user-name "Your name" user-name hubnet-send user-name "You have caught" caught hubnet-send user-name "# Attempts" attempts hubnet-send user-name "Relative %" (precision percent 2) hubnet-send user-name "Top hunter" leader hubnet-send user-name "Top hunter's catches" leader-caught end to listen-clients while [hubnet-message-waiting?] [ hubnet-fetch-message ifelse hubnet-enter-message? [add-player ] [ ifelse hubnet-exit-message? [remove-player] [ if ((hubnet-message-tag = "View") ) [ ask players with [ user-name = hubnet-message-source ] [ check-caught ] update-leader-stats ;; update all the players anytime we update the leaders ask players [ set-percent send-student-info ] ] ] ] ] end to update-leader-stats if any? players [ let leaders players with-max [ caught ] let number-leaders count leaders ifelse number-leaders > 1 [ set leader word number-leaders "-way tie" ] [ ask one-of leaders [set leader user-name ] ] set leader-caught [caught] of one-of leaders ] end ;;;;;;;;;;;;;;;;;;;;;; ;; Plotting Procedures ;;;;;;;;;;;;;;;;;;;;;; to update-plots set-current-plot "Avg. Bug Speed vs. Time" if any? bugs [plotxy time mean [speed] of bugs] set-current-plot "Current Bug Population" clear-plot foreach [1 2 3 4 5 6] [ set-current-plot-pen word "pen" ? plotxy ? count bugs with [speed = ?] ] ;; creates 6 different histograms of different colors in the same graph ;; each histogram is color coded to the color mapping for when the ;; SPEED-COLOR-MAP chooser is set to "rainbow" value. set-current-plot "Bugs Caught" clear-plot set-histogram-num-bars 8 set-current-plot-pen "pen1" plotxy 1 total-speed-1-caught set-histogram-num-bars 8 set-current-plot-pen "pen2" plotxy 2 total-speed-2-caught set-histogram-num-bars 8 set-current-plot-pen "pen3" plotxy 3 total-speed-3-caught set-histogram-num-bars 8 set-current-plot-pen "pen4" plotxy 4 total-speed-3-caught set-histogram-num-bars 8 set-current-plot-pen "pen5" plotxy 5 total-speed-5-caught set-histogram-num-bars 8 set-current-plot-pen "pen6" plotxy 6 total-speed-6-caught end
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