Re: insect population dynamics
- To: mathgroup at smc.vnet.net
- Subject: [mg24627] Re: insect population dynamics
- From: Mark Hunter <mhunter at ecology.uga.edu>
- Date: Fri, 28 Jul 2000 17:24:08 -0400 (EDT)
- Organization: University of Georgia
- References: <8lj8q0$8rr@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Many thanks for the variety of suggestions on how to handle my problem. I
received three different protocols, all of which worked. Which goes to
prove that there's more than one way to skin an insect.
Again, many thanks
Mark
Mark Hunter wrote:
> 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