Population dynamics of Müllerian mimicry under interspecific competition
Ecological Modelling, Vol. 220, No. 3, 424-429
Fuga Kumazawa(a), Takahiro Asami(b), Nariyuki Nakagiri(c), Kei-ichi Tainaka(a), Tatsuya Togashi(d), Tatsuo Miyazaki(d) & Jin Yoshimura(a, d, e)
(a) Department of Systems Engineering, Faculty of Engineering, Shizuoka University,
(b) Department of Biology, Shinshu University
(c) School of Human Science and Environment, University of Hyogo
(d) Marine Biosystems Research Center, Chiba University
(e) Department of Environmental and Forest Biology, State University of New York College of Environmental Science and Forestry
We ask what the effects of mutualism on population dynamics of two competitive species are. We model the population dynamics of mutualistic interactions with positive density- and frequency-dependences. We specifically assume the dynamics of Müllerian mimicry in butterflies, where the mortality of both species is reduced depending on the relative frequency of the other species. We assume that the two species are under Lotka–Volterra density-dependent competition. The equilibria are compared with the cases of competition alone. Unlike the traditional model of positive density-dependence, population explosion does not appear in the current dynamics, but the new equilibrium is simply achieved. It is because the effects of positive density- or frequency-dependence are restricted to parts of mortality. Both positive density- and frequency-dependences do promote coexistence of the mimetic species. However, the two models show a distinctive difference for coexistence. The effects of positive density-dependence are rather limited. In contrast, positive frequency-dependence always promotes coexistence, irrespective of environmental conditions. The results may imply that the evolutionary origin of Müllerian mimicry may depend on frequency-dependence (and density-dependence), but that its current population dynamics may depend solely on density-dependence. The role of frequency- and density-dependences on evolutionary dynamics is an open question.
Keywords: Müllerian mimicry; Density-dependence; Frequency-dependence; Mutualism
Ecological Modelling, Vol. 220, No. 3, 424-429
Fuga Kumazawa(a), Takahiro Asami(b), Nariyuki Nakagiri(c), Kei-ichi Tainaka(a), Tatsuya Togashi(d), Tatsuo Miyazaki(d) & Jin Yoshimura(a, d, e)
(a) Department of Systems Engineering, Faculty of Engineering, Shizuoka University,
(b) Department of Biology, Shinshu University
(c) School of Human Science and Environment, University of Hyogo
(d) Marine Biosystems Research Center, Chiba University
(e) Department of Environmental and Forest Biology, State University of New York College of Environmental Science and Forestry
We ask what the effects of mutualism on population dynamics of two competitive species are. We model the population dynamics of mutualistic interactions with positive density- and frequency-dependences. We specifically assume the dynamics of Müllerian mimicry in butterflies, where the mortality of both species is reduced depending on the relative frequency of the other species. We assume that the two species are under Lotka–Volterra density-dependent competition. The equilibria are compared with the cases of competition alone. Unlike the traditional model of positive density-dependence, population explosion does not appear in the current dynamics, but the new equilibrium is simply achieved. It is because the effects of positive density- or frequency-dependence are restricted to parts of mortality. Both positive density- and frequency-dependences do promote coexistence of the mimetic species. However, the two models show a distinctive difference for coexistence. The effects of positive density-dependence are rather limited. In contrast, positive frequency-dependence always promotes coexistence, irrespective of environmental conditions. The results may imply that the evolutionary origin of Müllerian mimicry may depend on frequency-dependence (and density-dependence), but that its current population dynamics may depend solely on density-dependence. The role of frequency- and density-dependences on evolutionary dynamics is an open question.
