Choose creature, bacteria or lizards. Choose your population size. These ecologies have no top predator. Much diversity can co-exist if the population is large enough. Diversity lasts longer in larger populations. Males of the "common side-blotched lizard" come in three varieties named after the color of their throats. Each has a different strategy for mating with females. Orange throats dominate large territories with lots of females. They use brute force to steal blue throats' females. So male orange throats beat blue throats. Yellow throats beat orange throats. Yellow throats sneak in oranges' territores to mate with their females. Blue throats beat yellow throats: Blue throats are monogamous. Focusing on one female, they can prevent yellows from sneaking in to steal their mates. There's no top variant (an intransitive ecology), as in rock-paper-scissors, but in this model each can be invaded only if next to three or more of it's "predators." There are 3 species of E. coli bacteria that act like this in a dish of nutrients. The dynamics are very similar to that of the side-blotched lizards. The 3 bacterial species oscillate in an ecology, usually coexisting in a dynamic equilibrium. No one species is inherently the top predator, each are equal (called "intransitive," see reference Liao and colleagues, 2020). Each strain has a strength and a weakness. C (rock) produces a toxin (colicin, C) that can kill S (scissors), but making that toxin slows C's growth. R (paper) is resistant to the toxin and grows faster than C, taking over its area. S (scissors) can outgrow R but is sensitive to the toxin. These strains can exist together as long as they live in patches where there is space to grow uninhibited by the others. If R grows into C’s patch, some of C might die out but C in turn can expand into S’s patch, while S can grow into R’s patch, etc. Dynamic balance and co-existence results, with spirally patterns and oscillations. These creatures make up a kind of ecological rock-paper-scissors game. Try on turbowarp.
This addresses a major question in biology: how so much diversity exists despite competition. One answer seems to be models much like this one. Lizard model based on Sinervo's field studies of three variants of the common side-blotched lizard. Bacteria model based Liao and colleagues studies (see references below). In both cases, the three variants co-exist competively in a rock-paper-scissors ecology. The size of population makes a big difference. Dynamic equilibrium becomes more likely with larger population size. On the coding end, I'm excited to have made this setup for different population sizes, scaling up numbers while scaling down images and so on. The bacteria images are by my wife, as I wanted a bacteria that looked like a rock, paper, and scissors. The three E. coli variants are like these images in several respects: one variant multiplies very quickly and forms sheet-like structures, another cuts, another is resistant to a toxin, and so on. References: Liao, Michael J Miano, Arianna Nguyen, Chloe B et al. Survival of the weakest in non-transitive asymmetric interactions among strains of E. coli. Journal: Nature communications, 11(1) Published 2020-11-27. Sinervo, B. & Lively, C. M. The rock–paper–scissors game and the evolution of alternative male strategies. Nature 380, 240–243 (1996). B. C. Kirkup, M. A. Riley, Antibiotic-mediated antagonism leads to a bacterial game of rock-paper-scissors in vivo. Nature 428, 412–414 (2004). Kirkup BC, Riley MA. Antibiotic-mediated antagonism leads to a bacterial game of rock-paper-scissors in vivo. Nature. 2004 Mar 25;428(6981):412-4.
