Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2000
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2000

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: insect population dynamics

  • To: mathgroup at smc.vnet.net
  • Subject: [mg24617] Re: insect population dynamics
  • From: "Seth Chandler" <SChandler at Central.UH.Edu>
  • Date: Fri, 28 Jul 2000 17:23:54 -0400 (EDT)
  • Organization: University of Houston
  • References: <8lj8q0$8rr@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

How about something like this to obtain a visual solution:

bughistory[ic_List,iters_]:=NestList[{#[[1]]*
        Exp[0.63((1 - #[[1]]/50)) - 0.068#[[2]]], #[[1]]*(1 -
            Exp[-0.068*#[[2]]])} &, ic, iters];



ListPlot[bughistory[{25,10},200],PlotJoined->True]

"Mark Hunter" <mhunter at ecology.uga.edu> wrote in message
news:8lj8q0$8rr at smc.vnet.net...
> I'm trying to use mathematica to run insect population models.  I'm new
> to the system, and wolfram support suggested that I post my question
> here.
>
> The models are simple predator-prey models.  They are non-linear
> simultaneous difference equations.  I've tried using RSolve, but it
> doesn't seem to handle the non-linearity.  Is there a way of using a
> Do-Loop for the same kind of thing?  A simple example of the model that
> I tried is:
>
> RSolve[{a[n + 1] == a[n]*Exp[0.63((1 - a[n]/50)) - 0.068b[n]],
>       b[n + 1] = a[n]*(1 - Exp[-0.068*b[n]]), a[0] == 25,
>       b[0] == 10}, {a[n], b[n]}, n]
>
> I want an output for variables a and n at time n, n+1, etc.
>
> I'd be most grateful for any advice that you can offer, and please don't
> underestimate my current level of ignorance.
>
> Many thanks,
>
> Mark Hunter
>




  • Prev by Date: Re: insect population dynamics
  • Next by Date: Re: Simlifying Sqrt[x^2] type args.
  • Previous by thread: Re: insect population dynamics
  • Next by thread: RE: insect population dynamics