文摘
In this paper, we study the asymptotic (large time) behaviour of a selection–mutation–competition model for a population structured with respect to a phenotypic trait when the rate of mutation is very small. We assume that the reproduction is asexual, and that the mutations can be described by a linear integral operator. We are interested in the interplay between the time variable t and the rate ε of mutations. We show that depending on class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0022247X16303523&_mathId=si1.gif&_user=111111111&_pii=S0022247X16303523&_rdoc=1&_issn=0022247X&md5=7ea1364a4f84806727f36082e9289c84" title="Click to view the MathML source">α>0class="mathContainer hidden">class="mathCode">, the limit class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0022247X16303523&_mathId=si2.gif&_user=111111111&_pii=S0022247X16303523&_rdoc=1&_issn=0022247X&md5=8dea560db55b8b01399e60ccf0ea98dc" title="Click to view the MathML source">ε→0class="mathContainer hidden">class="mathCode"> with class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0022247X16303523&_mathId=si3.gif&_user=111111111&_pii=S0022247X16303523&_rdoc=1&_issn=0022247X&md5=e84b638d5ce3042cf0091038473ef79d" title="Click to view the MathML source">t=ε−αclass="mathContainer hidden">class="mathCode"> can lead to population number densities which are either Gaussian-like (when α is small) or Cauchy-like (when α is large).