Question

have I solved these correctly? (Lotka-Volterra model)

Numbered Suppose that porcupines are the only prey and available food source for fisher, and that the predator-prey interaction follows Lotka-Volterra dynamics. The mortality rate of fisher in the absence of porcupines is 0.2 per week, and the intrinsic growth rate of porcupine is 0.3 per week. The capture efficiency of porcupine by fisher is 0.002, and the efficiency at which porcupine biomass is converted to fisher offspring is 0.1. 3a. If there are 50 fisher in a population, and 120 porcupines are present, what is the rate per week that porcupines will be killed? 24 porcupines will be killed each week. 3b. If there are initially 50 fisher and 120 porcupines, the overall rate of change in the prey population will be a gain or loss (highlight one) of how many porcupines per week? There will be a loss of 7.2 porcupines per week. 3c. If there are 50 fisher in a population and no porcupine, what is the rate per week that fisher will die? 10 fisher will die per week. 3d. If there are initially 50 fisher and 120 porcupines, the net growth rate in the predator population will be a gain or loss (highlight one) of how many fisher per week? There will be a growth rate of 0.2 fisher per week. 3e. Based on the population data of fisher and porcupine that you calculated above, circle the correct quadrant on the graph below where their population cycle is currently situated. Quadrant 1

Answer 1

I think this is correct.

You just needed to put the values given in the question in the prey-predator equation of the Lotka Volterra model which is :

dH/dt=rH-aHP and dP/dt= bHP-mP

H = density of prey
P = density of predators
r = intrinsic rate of prey population increase
a = predation rate coefficient
b = reproduction rate of predators per 1 prey eaten
m = predator mortality rate

The variables may differ in different books .