The unique positive equilibrium of dynamics (3).

<p>The red curves correspond to the second equation of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0142929#pone.0142929.e008" target="_blank">Eq (4)</a> and the green curves to the first equation of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0142929#pone.0142929.e008" target="_blank">Eq (4)</a>. For any given <i>p</i> and <i>q</i>, the two curves have a unique positive intersection (see the black spots). Parameters are taken as <i>β</i>₁ = <i>β</i>₂ = 0.01, <i>α</i>₁ = 0.75, <math><mrow><mi>f</mi><mo>¯</mo><mo>=</mo><mn>0</mn><mo>.</mo><mn>25</mn></mrow></math>, <i>c</i>₁ = 0.5 and <i>c</i>₂ = 0.5 in all two panels. Furthermore, <i>α</i>₂ = 0.55 and <math><mrow><mi>g</mi><mo>¯</mo><mo>=</mo><mn>0</mn><mo>.</mo><mn>2</mn></mrow></math> in panel <b>a</b>, and <i>α</i>₂ = 1 and <math><mrow><mi>g</mi><mo>¯</mo><mo>=</mo><mn>0</mn><mo>.</mo><mn>5</mn></mrow></math> in panel <b>b</b>.